rexresearch
Cassandra QUAVE, et al.
Herbs vs MRSA
http://preventdisease.com/news/17/021317_Peppertree-Disarms-Most-Dangerous-Bacteria.shtml
Prevent Disease
Common weed found to disarm MRSA superbug
by Karen
Foster
Superbugs are without a doubt a major threat affecting all
health care systems. Methicillin-resistant Staphylococcus aureus
(MRSA) infection is caused by a type of staph bacteria that's
become resistant to many of the antibiotics used to treat
ordinary staph infections. Despite attempts by new antibiotics
to neutralize the effects of MRSA, none have succeeded. But
nature did.
The red berries of the Brazilian peppertree -- a weedy, invasive
species common in Florida -- contain an extract with the power
to disarm dangerous antibiotic-resistant staph bacteria,
scientists at Emory University have discovered.
The journal Scientific Reports is publishing the finding, made
in the lab of Cassandra Quave, an assistant professor in Emory's
Center for the Study of Human Health and in the School of
Medicine's Department of Dermatology.
"Traditional healers in the Amazon have used the Brazilian
peppertree for hundreds of years to treat infections of the skin
and soft tissues," Quave says. "We pulled apart the chemical
ingredients of the berries and systematically tested them
against disease-causing bacteria to uncover a medicinal
mechanism of this plant."
The researchers showed that a refined, flavone-rich composition
extracted from the berries inhibits formation of skin lesions in
mice infected with MRSA. The compound works not by killing the
MRSA bacteria, but by repressing a gene that allows the bacteria
cells to communicate with one another. Blocking that
communication prevents the cells from taking collective action,
a mechanism known as quorum quenching.
"It essentially disarms the MRSA bacteria, preventing it from
excreting the toxins it uses as weapons to damage tissues,"
Quave says. "The body's normal immune system then stands a
better chance of healing a wound."
While infections are becoming increasingly difficult to beat, no
new class of antibiotic has been discovered since 1987. In
contrast, a new infection emerges on an almost yearly basis.
The discovery may hold potential for new ways to treat and
prevent antibiotic-resistant infections, a growing international
problem. Antibiotic-resistant infections annually cause at least
two million illnesses and 23,000 deaths in the United States,
according to the Centers for Disease Control and Prevention. The
United Nations last year called antibiotic-resistant infections
a "fundamental threat" to global health and safety, citing
estimates that they cause at least 700,000 deaths each year
worldwide, with the potential to grow to 10 million deaths
annually by 2050.
Bacteria are rife in conventionally grown US meat including
antibiotic-resistant bacteria also known as superbugs. Almost
half of beef, chicken, pork and turkey in samples tested from US
grocery stores contained staph bacteria reported the Los Angeles
Times in 2011 including the resistant MRSA staph bacterium
(methicillin-resistant S. aureus). Pork tested by Consumer
Reports in 2013 also contained MRSA and four other kinds of
resistant bacteria.
Blasting deadly bacteria with drugs designed to kill them is
helping to fuel the problem of antibiotic resistance. Some of
the stronger bacteria may survive these drug onslaughts and
proliferate, passing on their genes to offspring and leading to
the evolution of deadly "super bugs."
In contrast, the Brazilian peppertree extract works by simply
disrupting the signaling of MRSA bacteria without killing it.
The researchers also found that the extract does not harm the
skin tissues of mice, or the normal, healthy bacteria found on
skin.
"In some cases, you need to go in heavily with antibiotics to
treat a patient," Quave says. "But instead of always setting a
bomb off to kill an infection, there are situations where using
an anti-virulence method may be just as effective, while also
helping to restore balance to the health of a patient. More
research is needed to better understand how we can best leverage
anti-virulence therapeutics to improve patient outcomes."
Quave, a leader in the field of medical ethnobotany and a member
of the Emory Antibiotic Resistance Center, studies how
indigenous people incorporate plants in healing practices to
uncover promising candidates for new drugs.
The Brazilian peppertree (Schinus terebinthifolia) is native to
South America but thrives in subtropical climates. It is
abundant in much of Florida, and has also crept into southern
areas of Alabama, Georgia, Texas and California. Sometimes
called the Florida holly or broad leaf peppertree, the woody
plant forms dense thickets that crowd out native species.
"The Brazilian peppertree is not some exotic and rare plant
found only on a remote mountaintop somewhere," Quave says. "It's
a weed, and the bane of many a landowner in Florida."
From an ecological standpoint, it makes sense that weeds would
have interesting chemistry, Quave adds. "Persistent, weedy
plants tend to have a chemical advantage in their ecosystems,
which help may protect them from diseases so they can more
easily spread in a new environment."
https://en.wikipedia.org/wiki/Schinus_terebinthifolius
Schinus terebinthifolius
Starr 041018-0009 Schinus terebinthifolius.jpg
Scientific classification
Kingdom: Plantae, Angiosperms, Eudicots, Rosids, Order:
Sapindales; Family: Anacardiaceae; Genus: Schinus ; Species: S.
terebinthifolia
Binomial name : Schinus terebinthifolia Raddi, 1820[1]
Schinus terebinthifolia is a species of flowering plant in the
cashew family, Anacardiaceae, that is native to subtropical and
tropical South America (southeastern Brazil, northern Argentina,
and Paraguay). It is found in these states of Brazil: Alagoas,
Bahia, Espírito Santo, Mato Grosso do Sul, Minas Gerais,
Pernambuco, Paraná, Rio de Janeiro, Rio Grande do Norte, Rio
Grande do Sul, Santa Catarina, São Paulo, and Sergipe. Common
names include Brazilian peppertree,[2] aroeira, rose pepper,
broadleaved pepper tree,[3] wilelaiki (or wililaiki),[4] and
Christmasberry.[5]
Description
Brazilian peppertree is a sprawling shrub or small tree, with a
shallow root system, reaching a height of 7–10 m. The branches
can be upright, reclining, or nearly vine-like, all on the same
plant. Its plastic morphology allows it to thrive in all kinds
of ecosystems: from dunes to swamps, where it grows as a
semiaquatic plant.[6] The leaves are alternate, 10–22 cm long,
pinnately compound with (3–) 5–15 leaflets; the leaflets are
roughly oval (lanceolate to elliptical), 3–6 cm long and 2–3.5
cm broad, and have finely toothed margins, an acute to rounded
apex and yellowish veins. The leaf rachis between the leaflets
is usually (but not invariably) slightly winged. The plant is
dioecious, with small white flowers borne profusely in axillary
clusters. The fruit is a drupe 4–5 mm diameter, carried in dense
clusters of hundreds.
The two varieties are:
S. terebinthifolius var. acutifolius, leaves to 22 cm, with 7–15
leaflets, fruit pink
S. terebinthifolius var. terebinthifolius, leaves to 17 cm, with
5–13 leaflets, fruit red
Cultivation
and uses
Brazilian pepper is widely grown as an ornamental plant in
frost-free regions of South America for its foliage and fruit.
It is considered as a melliferous flower[6] and is the main
source of food for the bee Tetragonisca angustula, which is an
important honey producer.[7]
Although it is not a true pepper (Piper), its dried drupes are
often sold as pink peppercorns, as are the fruits from the
related species Schinus molle (Peruvian peppertree). The seeds
can be used as a spice, adding a pepper-like taste to food. They
are usually sold in a dry state and have a bright pink color.
They are less often sold pickled in brine, where they have a
dull, almost green hue.
In the United States, it has been introduced to California,
Texas, Hawaii, Arizona, Nevada, Louisiana,[8] and Florida.
Planted originally as an ornamental outside of its native range,
Brazilian pepper has become widespread and is considered an
invasive species in many subtropical regions with moderate to
high rainfall, including parts or all of Australia, the Bahamas,
Bermuda, southern China, Cuba, Fiji, French Polynesia, Guam,
Hawaii, Malta, the Marshall Islands, Mauritius, New Caledonia,
New Zealand, Norfolk Island, Puerto Rico, Réunion, South Africa,
and the United States. In drier areas, such as Israel and
southern California, it is also grown, but has not generally
proved invasive. In California, it is considered invasive in
coastal regions by the California Invasive Plant Council
(www.cal-ipc.org.)
Brazilian pepper is hard to control because it produces basal
shoots if the trunk is cut. Trees also produce abundant seeds
that are dispersed by birds and ants. This same hardiness makes
the tree highly useful for reforestation in its native
environment, but enables it to become invasive outside of its
natural range.[6]
Toxicity
Like many other species in the family Anacardiaceae, Brazilian
pepper has an aromatic sap that can cause skin reactions
(similar to poison ivy burns) in some sensitive people –
although the reaction is usually weaker than that induced by
touch of the closely related Lithraea molleoides, known in
Brazil as "wild" aroeira (aroeira brava). Conversely, Schinus
terebinthifolius is commonly known as "tame" aroeira (aroeira
mansa).
In a paper on triterpenes, the ingested fruits are noted to have
a “paralyzing effect” on birds.[9] The narcotic and toxic
effects on birds and other wildlife has also been noted by
others, e.g., Bureau of Aquatic Plant Management. The AMA
Handbook of Poisonous and Injurious Plants reports that the
triterpenes found in the fruits can result in irritation of the
throat, gastroenteritis, diarrhea, and vomiting in man.[10] Like
most other members of the Anacardiaceae, Brazilian pepper
contains active alkenyl phenols, e.g., urushiol, cardol, which
can cause contact dermatitis and inflammation in sensitive
individuals.[11][12] Contact with the “sap” from a cut or
bruised tree can result in rash, lesions, oozing sores, severe
itching,reddening and swelling (especially of the eyes), and
welts.[13]
The burning of plant matter releases many airborne irritants, so
is not an effective means of control. It is said to have a
"mace-like" effect upon nearby people and is highly advised
against.
History
"Florida holly" was introduced to Florida by at latest 1891,
probably earlier,[14] where it has spread rapidly since about
1940,[15] replacing native plants, like mangroves, with
thousands of acres occupied. It is especially adept at
colonizing disturbed sites and can grow in both wet and dry
conditions. Its growth habit allows it to climb over understory
trees and invade mature canopies, forming thickets that choke
out most other plants.
Legal
status
The species, including the seed, is legally prohibited from
sale, transport, or planting in Florida, according to the
Florida Department of Agriculture and Consumer Services Noxious
Weed List.[16] It is classified as a Category I pest by The
Florida Exotic Pest Plant Council (FL EPPC).[17] To keep the
plant from spreading into native plant communities and
displacing them, local regulations and environmental guidelines
require eradication of Brazilian pepper wherever possible. The
plant and all parts are also illegal for sale or transfer in
Texas.[18] As one of the two species sold as pink peppercorn,
the other being Schinus molle, it lacks generally recognized as
safe (GRAS) status with the FDA.[19]
It is a declared weed in several states of
Australia.[20][21][22] In South Africa, it is classified as a
category 1 invader in KwaZulu-Natal province, where any plants
are to be removed and destroyed, and a category 3 invader in all
other provinces, meaning it may no longer be planted.[23]
Control
Two herbicides are approved for use in the United States to
exterminate Brazilian pepper: Triclopyr, using the basal bark
method; and glyphosate. Picloram can be used if the stump has
been freshly cut, but this is not the preferred nor most
effective means of eradication.
Medicinal
uses
Peppertree is the subject of extensive folk medicinal lore where
it is indigenous. Virtually all parts of this tropical tree,
including its leaves, bark, fruit, seeds, resin, and oleoresin
(or balsam) have been used medicinally by indigenous peoples
throughout the tropics. The plant has a very long history of use
and appears in ancient religious artifacts and on idols among
some of the ancient Chilean Amerindians.[citation needed]
Throughout South and Central America, Brazilian peppertree is
reported to be an astringent, antibacterial, diuretic, digestive
stimulant, tonic, antiviral, and wound healer. In Peru, the sap
is used as a mild laxative and a diuretic, and the entire plant
is used externally for fractures and as a topical antiseptic.
The oleoresin is used externally as a wound healer, to stop
bleeding, and for toothaches, and it is taken internally for
rheumatism and as a purgative. In South Africa, a leaf tea is
used to treat colds, and a leaf decoction is inhaled for colds,
hypertension, depression, and irregular heart beat. In the
Brazilian Amazon, a bark tea is used as a laxative, and a
bark-and-leaf tea is used as a stimulant and antidepressant. In
Argentina, a decoction is made with the dried leaves and is
taken for menstrual disorders and is also used for respiratory
and urinary tract infections and disorders.[citation needed]
Brazilian peppertree is still employed in herbal medicine today
in many countries. It is used for many conditions in the
tropics, including menstrual disorders, bronchitis, gingivitis,
gonorrhea, gout, eye infections, rheumatism, sores, swellings,
tuberculosis, ulcers, urethritis, urogenital disorders, venereal
diseases, warts, and wounds. In Brazilian herbal medicine today,
the dried bark and/or leaves are employed for heart problems
(hypertension and irregular heart beat), infections of all
sorts, menstrual disorders with excessive bleeding, tumors, and
general inflammation. A liquid extract or tincture prepared with
the bark is used internally as a stimulant, tonic, and
astringent, and externally for rheumatism, gout, and syphilis.
[24]
Recently, the fruit of the plant has been studied and shows
promise as a treatment for MRSA. A chemical in the berry appears
to stop bacteria from producing a toxin which breaks down
tissue. It also appears to suppress the way the bacteria
communicate. [25]
References
"Schinus terebinthifolia Raddi". Germplasm Resources Information
Network. United States Department of Agriculture. 2009-03-30.
Retrieved 2009-12-30.
"Schinus terebinthifolius". Natural Resources Conservation
Service PLANTS Database. USDA. Retrieved 6 November 2015.
"Broadleaved pepper tree (Schinus terebinthifolius)".
www.daf.qld.gov.au. Retrieved 2015-07-19.
"Christmas-berry" (PDF). Retrieved 2016-12-04.
(Portuguese) Schinus terebinthifolius at Instituto de Pesquisas
e Estudos Florestais
Paulo Backes & Bruno Irgang, Mata Atlântica: as árvores e a
paisagem, Porto Alegre, Paisagem do Sul, 2004, page 102
Braga, JA; Sales, EO; Soares Neto, J; Conde, MM; Barth, OM;
Maria, CL (December 2012). "Floral sources to Tetragonisca
angustula (Hymenoptera: Apidae) and their pollen morphology in a
Southeastern Brazilian Atlantic Forest.". Revista de biologia
tropical. 60 (4): 1491–501. doi:10.15517/rbt.v60i4.2067. PMID
23342504.
"Schinus terebinthifolius; Element stewardship abstract" (PDF).
Campello, J.P. and A.J. Marsaioli. 1974. Triterpenes of
Schinusterebinthifolius. Phytochem. 13: 659-660
Lampe, K.F. and M.A. McCann. 1985. AMA Handbook of Poisonous and
Injurious Plants.American Medical Association, Chicago.
Lampe, K.F. and R. Fagerstrom. 1968. Plant Toxicity and
Dermatitis. Williams & Wilkins Co.,Baltimore
Tomlinson, P.B. 1980. The Biology of Trees Native to Tropical
Florida. Harvard University Printing Office, Allston.
Morton, J.F. 1978. Brazilian pepper - Its impact on people,
animals and the environment. Econ. Bot.32: 353-359.
Gogue, G. J.; Hurst, C. J.; Bancroft, L. (1974). "Growth
inhibition by Schinus terebinthifolius". HortScience. 9 (3):
301.
Ewel, J. J. 1986. Invasibility: Lessons from south Florida. in
H. A. Mooney and J. A. Drake, eds. Ecology of biological
invasions of North America and Hawaii, pp. 214–230.
Springer-Verlag, New York.
(F.A.C. 5B-57.007)
http://www.doacs.state.fl.us/pi/enpp/botany/noxweed.html Florida
Department of Agriculture & Consumer Services
Florida Florida Exotic Pest Plant Council
Texas Invasives
Singh, Ram J.; Lebeda, Ales; Tucker, Arthur O. (2011). "2.
Medicinal Plants—Nature's Pharmacy". In Singh, Ram J. Genetic
Resources, Chromosome
Engineering, and Crop Improvement: Medicinal Plants. 6. CRC
Press (published 15 September 2011). p. 17. ISBN 978-1420073843.
Broadleaved pepper tree Schinus terebinthifolius Declared Class
3 (PDF)
Broad-leaf pepper tree
Swan Weeds — List of Weeds
"Invasive Alien Plants - CARA List". South African Nursery
Association.
"Tropical Plant Database".
https://www.washingtonpost.com/news/to-your-health/wp/2017/02/10/common-weed-could-help-fight-deadly-superbug-study-finds/#pt0-293591
https://www.nytimes.com/2016/09/18/magazine/could-ancient-remedies-hold-the-answer-to-the-looming-antibiotics-crisis.html?_r=0
Could
Ancient Remedies Hold the Answer to the Looming Antibiotics
Crisis?
One
researcher thinks the drugs of the future might come from
the past: botanical treatments long overlooked by Western
medicine.
By FERRIS
JABR
...Recently, Quave and her research team have discovered that an
extract of Brazilian peppertree berries — an invasive species
common in many warmer parts of the United States — prevents MRSA
from forming skin lesions in mice and shrinks biofilms formed by
the bacteria. “I really believe these kind of inhibitors are a
major part of the solution to antibiotic resistance,” Quave
says. “We can shut down bacteria’s most dangerous machinery
without killing them.” She envisions using such drugs as
prophylactics in surgeries with a high infection risk, or in
combination with other antimicrobials if a serious infection is
already established...
https://www.researchgate.net/profile/Cassandra_Quave/publications
https://www.researchgate.net/publication/313592977_Virulence_Inhibitors_from_Brazilian_Peppertree_Block_Quorum_Sensing_and_Abate_Dermonecrosis_in_Skin_Infection_Models
Scientific Reports 7:42275 (February 2017)
DOI: 10.1038/srep42275
Virulence
Inhibitors from Brazilian Peppertree Block Quorum Sensing
and Abate Dermonecrosis in Skin Infection Models
Amelia
Muhs, et al.
https://www.sciencedaily.com/releases/2015/08/150821164150.htm
Chestnut
leaves yield extract that disarms deadly staph bacteria
Extract shuts down staph without boosting its drug
resistance
Leaves of the European chestnut tree contain ingredients with
the power to disarm dangerous staph bacteria without boosting
its drug resistance, scientists have found.
PLOS ONE is publishing the study of a chestnut leaf extract,
rich in ursene and oleanene derivatives, that blocks
Staphlococcus aureus virulence and pathogenesis without
detectable resistance.
The use of chestnut leaves in traditional folk remedies inspired
the research, led by Cassandra Quave, an ethnobotanist at Emory
University.
"We've identified a family of compounds from this plant that
have an interesting medicinal mechanism," Quave says. "Rather
than killing staph, this botanical extract works by taking away
staph's weapons, essentially shutting off the ability of the
bacteria to create toxins that cause tissue damage. In other
words, it takes the teeth out of the bacteria's bite."
The discovery holds potential for new ways to both treat and
prevent infections of methicillin-resistant S. aureus, or MRSA,
without fueling the growing problem of drug-resistant pathogens.
Antibiotic-resistant bacteria annually cause at least two
million illnesses and 23,000 deaths in the United States,
according to the Centers for Disease Control and Prevention.
MRSA infections lead to everything from mild skin irritations to
fatalities. Evolving strains of this "super bug" bacterium pose
threats to both hospital patients with compromised immune
systems and young, healthy athletes and others who are in close
physical contact.
"We've demonstrated in the lab that our extract disarms even the
hyper-virulent MRSA strains capable of causing serious
infections in healthy athletes," Quave says. "At the same time,
the extract doesn't disturb the normal, healthy bacteria on
human skin. It's all about restoring balance."
Quave, who researches the interactions of people and plants -- a
specialty known as ethnobotany -- is on the faculty of Emory's
Center for the Study of Human Health and Emory School of
Medicine's Department of Dermatology. She became interested in
ethnobotany as an undergraduate at Emory.
For years, she and her colleagues have researched the
traditional remedies of rural people in Southern Italy and other
parts of the Mediterranean. "I felt strongly that people who
dismissed traditional healing plants as medicine because the
plants don't kill a pathogen were not asking the right
questions," she says. "What if these plants play some other role
in fighting a disease?"
Hundreds of field interviews guided her to the European chestnut
tree, Castanea sativa. "Local people and healers repeatedly told
us how they would make a tea from the leaves of the chestnut
tree and wash their skin with it to treat skin infections and
inflammations," Quave says.
For the current study, Quave teamed up with Alexander Horswill,
a microbiologist at the University of Iowa whose lab focuses on
creating tools for use in drug discovery, such as
glow-in-the-dark staph strains.
The researchers steeped chestnut leaves in solvents to extract
their chemical ingredients. "You separate the complex mixture of
chemicals found in the extract into smaller batches with fewer
chemical ingredients, test the results, and keep honing in on
the ingredients that are the most active," Quave explains. "It's
a methodical process and takes a lot of hours at the bench.
Emory undergraduates did much of the work to gain experience in
chemical separation techniques."
The work produced an extract of 94 chemicals, of which ursene
and oleanene based compounds are the most active.
Tests showed that this extract inhibits the ability of staph
bacteria to communicate with one another, a process known as
quorum sensing. MRSA uses this quorum-sensing signaling system
to manufacture toxins and ramp up its virulence.
"We were able to trace out the pathways in the lab, showing how
our botanical extract blocks quorum sensing and turns off toxin
production entirely," Quave says. "Many pharmaceutical companies
are working on the development of monoclonal antibodies that
target just one toxin. This is more exciting because we've shown
that with this extract, we can turn off an entire cascade
responsible for producing a variety of different toxins."
A single dose of the extract, at 50 micrograms, cleared up MRSA
skin lesions in lab mice, stopping tissue damage and red blood
cell damage. The extract does not lose activity, or become
resistant, even after two weeks of repeated exposure. And tests
on human skin cells in a lab dish showed that the botanical
extract does not harm the skin cells, or the normal skin
micro-flora.
The Emory Office of Technology Transfer has filed a patent for
the discovery of the unique properties of the botanical extract.
The researchers are doing further testing on individual
components of the extract to determine if they work best in
combination or alone.
"We now have a mixture that works," Quave says. "Our goal is to
further refine it into a simpler compound that would be eligible
for FDA consideration as a therapeutic agent."
Potential uses include a preventative spray for football pads or
other athletic equipment; preventative coatings for medical
devices and products such as tampons that offer favorable
environments for the growth of MRSA; and as a treatment for MRSA
infections, perhaps in combination with antibiotics.
"It's easy to dismiss traditional remedies as old wives' tales,
just because they don't attack and kill pathogens," Quave says.
"But there are many more ways to help cure infections, and we
need to focus on them in the era of drug-resistant bacteria."
http://grantome.com/grant/NIH/R01-AT007052-04
Mechanistic
Studies on Staphylococcal Quorum Quenching Natural Products
Quave,
Cassandra Leah
Emory
University, Atlanta, GA, United State
Abstract
Staphylococcus aureus is a highly problematic pathogen. Rates of
infection in both the community and healthcare setting are on
the rise, and coupled with its highly antibiotic-resistant
nature, this makes S. aureus a top public health concern. In
fact, invasive methicillin-resistant S. aureus (MRSA) is
responsible for more deaths in the USA than AIDS. Nevertheless,
the number of new antibiotic leads in the pipeline is
diminishing, and many scientists have put out a call for the
discovery and development of a new class of drugs which could
mediate microbial pathogenicity rather than growth and survival.
The staphylococcal quorum-sensing pathway, controlled by the
accessory gene regulator (agr) system, is a potential target for
such anti-pathogenic drug discovery efforts, as it serves as a
global regulator of staphylococcal virulence. Following
extensive studies on the complementary and alternative medical
(CAM) practices of southern Italians in the treatment of skin
and soft tissue infection, over 100 plant samples were
identified, collected, extracted, and examined for their
anti-staphylococcal potential. Among the tests included was a
screen for the inhibition of??-hemolysin, a translational
protein product of RNAIII, whose production is regulated through
the agr quorum-sensing pathway. Extract 134, which is derived
from a popular tree with edible fruits and medicinal leaves and
bark, was found to exhibit a strong dose-dependent inhibition of
?-hemolysin at sub-inhibitory concentrations for growth. The
dose-dependent quorum-quenching effects of Extract 134 were
confirmed through the use of fluorescent genetic reporters for
agr (types I-IV). This activity is important based upon previous
animal studies with agr knockout mutants that show a diminished
capacity to initiate and persist in a skin infection model. In
the proposed study, we seek to improve our understanding of the
mechanistic basis for Extract 134's quorum-quenching effects and
evaluate the therapeutic relevance of such an anti-virulence
therapy using in vivo models. The study will address four
specific aims: 1) identification and structural elucidation of
the active constituent(s) (or marker compounds for
standardization) in Extract 134;2) elucidation of the mechanism
of action for the quorum-quenching effects observed;3)
determination of drug metabolism and pharmacokinetic parameters
(DM/PK) of the bioactive constituent(s);and 4) evaluation of
efficacy in treating S. aureus skin infection in a murine model.
PLoS ONE
11(9):e0163655 (September 2016 )
DOI: 10.1371/journal.pone.0163655
Correction:
Castanea sativa (European Chestnut) Leaf Extracts Rich in
Ursene and Oleanene Derivative...
Hospital
superbug MRSA could be beaten with an unusual cure
Researchers
used a Mediterranean folk remedy to obtain an extract that
stopped staphylococcus aureus producing harmful toxins in
mice
By John
von Radowitz
Chemicals from sweet chestnut tree leaves can help fight the
MRSA superbug, scientists have found.
They used a Mediterranean folk remedy to obtain an extract that
stopped staphylococcus aureus producing harmful toxins in mice.
Cassandra Quave of Emory University, Atlanta, Georgia, said it
did not kill the bug but “takes the teeth out of the bacteria’s
bite”.
The compounds "disarm" Staphylococcus aureus bacteria and stop
them producing harmful toxins.
Yet they do not appear to boost levels of drug resistance.
Dr Quave said: "Rather than killing staph, this botanical
extract works by taking away staph's weapons, essentially
shutting off the ability of the bacteria to create toxins that
cause tissue damage."
For years the Emory team had investigated the traditional
remedies of rural people in southern Italy and other parts of
the Mediterranean.
Detective work by the researchers led them to the European sweet
chestnut tree, Castanea sativa.
"Local people and healers repeatedly told us how they would make
a tea from the leaves of the chestnut tree and wash their skin
with it to treat skin infections and inflammations," said Dr
Quave.
In the laboratory, the scientists steeped chestnut leaves in
solvents to extract 94 chemicals including the anti-bacterial
ursene and oleanene compounds.
A single 50 microgram dose of the extract cleared up MRSA skin
infections in laboratory mice, halting damage to tissue and red
blood cells.
http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0136486
PLOS ONE, 2015; 10 (8): e0136486
DOI: 10.1371/journal.pone.0136486
Castanea
sativa (European Chestnut) Leaf Extracts Rich in Ursene and
Oleanene Derivatives Block Staphylococcus aureus Virulence
and Pathogenesis without Detectable Resistance.
Cassandra
L. Quave, James T. Lyles, Jeffery S. Kavanaugh, Kate Nelson,
Corey P. Parlet, Heidi A. Crosby, Kristopher P. Heilmann,
Alexander R. Horswill.
Abstract
The Mediterranean is home to a rich history of medical
traditions that have developed under the influence of diverse
cultures over millennia. Today, many such traditions are still
alive in the folk medical practices of local people.
Investigation of botanical folk medicines used in the treatment
of skin and soft tissue infections led us to study Castanea
sativa (European Chestnut) for its potential antibacterial
activity. Here, we report the quorum sensing inhibitory activity
of refined and chemically characterized European Chestnut leaf
extracts, rich in oleanene and ursene derivatives (pentacyclic
triterpenes), against all Staphylococcus aureus accessory gene
regulator (agr) alleles. We present layers of evidence of agr
blocking activity (IC50 1.56–25 µg mL-1), as measured in toxin
outputs, reporter assays hemolytic activity, cytotoxicity
studies, and an in vivo abscess model. We demonstrate the
extract’s lack of cytotoxicity to human keratinocytes and murine
skin, as well as lack of growth inhibitory activity against S.
aureus and a panel of skin commensals. Lastly, we demonstrate
that serial passaging of the extract does not result in
acquisition of resistance to the quorum quenching composition.
In conclusion, through disruption of quorum sensing in the
absence of growth inhibition, this study provides insight into
the role that non-biocide inhibitors of virulence may play in
future antibiotic therapies.
A series of studies by Quave et al. [4–6] investigated the
bioactivity of plant extracts used in the traditional treatment
of skin and soft tissue infections (SSTI) in Italy. Extracts
were screened for activity against multiple targets, including
S. aureus biofilms, communication (quorum-sensing) and growth.
As a result of this work, three potential leads (Castanea
sativa, Ballota nigra, and Sambucus ebulus) for the inhibition
of quorum sensing in the absence of growth-inhibitory effects
were identified [4]. Here, we continue to explore other
mechanisms by which anti-infective traditional botanical
medicines may function, and report the discovery of quorum
quenching natural products extracted from Castanea sativa
(European Chestnut) leaves, which are used in traditional
therapies for treating skin inflammation SSTIs in the
Mediterranean [7]. Notably, we report the ability of C. sativa
leaf extracts to attenuate virulence by quenching S. aureus
agr-mediated quorum sensing, effectively blocking production of
harmful exotoxins at sub-inhibitory concentrations for growth.
We also report the lack of cytotoxicity to human skin cells,
lack of growth inhibitory activity against the normal skin
microflora, lack of resistance development, and efficacy in a
skin abscess animal model...
Extraction
and purification of QSI-containing fractions
Crude methanol extracts (Extract 224) of the ground leaves were
created by maceration of the plant materials at room temperature
using a ratio of 1g dry leaves:10 mL MeOH for two successive
periods of 72 hours, with daily agitation. Filtered extracts
were combined, concentrated at reduced pressure and a
temperature <40°C with rotary evaporators, and lyophilized
before being re-suspended in water and partitioned in succession
with hexane, ethyl acetate and butanol (all solvents acquired
from Fisher Chemical, Certified ACS). The resulting non-aqueous
partitions were dried over anhydrous Na2SO4, concentrated in
vacuo, and lyophilized before testing for activity.
The most active partition (ethyl acetate, extract 224C) was
subjected to further fractionation using a CombiFlash Rf+
(Teledyne ISCO) flash chromatography system using a RediSep Rf
Gold silica column. Extract 224C was bonded to Celite 545 (Acros
Organics) at a 1:4 ratio and dry-loaded using a RediSep dry load
cartridge. The mobile phase consisted of (A) hexane, (B) EtOAc,
and (C) MeOH. The linear gradient begins with 100% A for 6.3
column volumes (CV), and then increased to 50:50 A:B by25.3 CV,
and increased to 100% B at 63.3 CV, which was held until 69.6
CV, and then to 70:30 B:C at 88.6 CV, which was held until 94.9
CV. The chromatography was monitored at 254 and 280 nm, as well
as via ELSD. The resulting fractions were combined into 5
fractions. Following further bioassay testing, it was determined
that the fraction which eluted from 30–40 CV (224C-F2) was most
active. The full extract fractionation scheme is presented in
Fig 2...
Discussion
The ethnobotanical approach to drug discovery [55] was used here
to identify Castanea sativa leaves as a potential source new
anti-infective agents. Through design of a bioactivity-guided
fractionation strategy based on limited growth-impact coupled to
quorum sensing inhibition, we were successful in creating a
highly efficacious botanical composition with universal
quenching activity for all agr alleles. To the best of our
knowledge, the present work represents the first in-depth
investigation of European Chestnut leaf extract for its quorum
quenching and anti-virulence effects since its identification as
a potential quorum quenching lead [4]. Furthermore, this is the
first report of the quorum quenching effects of a botanical
composition rich in ursene and oleanene derivatives (Fig 10)
against S. aureus. Additional compounds identified in the most
active region (at <1% relative abundance each) included
putative gallotannins, which share a tri-galloyl structure with
varying core sugars (32, 33, 34), and a putative ellagitannin
(39). It is possible that in addition to the pentacyclic
triterpenes present in 224C-F2, hydrolysable tannins also
contribute to the extract’s quorum quenching activity.
European Chestnut leaf extracts have been the focus of a number
of studies centered on evaluation of its activity in scavenging
reactive oxygen species [42, 56] and cytoprotective effects,
specifically with regards to protection from UV-damage in skin
cells [57]. The examination of European Chestnut leaf extracts
with a patch test revealed that with respect to irritant
effects, such extracts can be considered as safe for topical
applications [58]. The integration of C. sativa leaf extracts
into cosmetic compositions has also been patented, and is based
on the antibacterial and reactive oxygen species (ROS)
scavenging effects of the extract [59]. Our safety studies in
both human keratocytes (HaCaT cells) and murine skin (Fig 6)
have reconfirmed that this version of European Chestnut leaf
extract (224C-F2) can be considered safe for topical
applications based on its lack of cytotoxic and irritant
effects.
Several layers of evidence in support of the efficacy of C.
sativa leaf extracts in blocking S. aureus virulence have been
presented. Specifically, we have demonstrated that European
Chestnut leaf extracts are effective in blocking production of
the translational products of RNAIII, including a number of
exotoxins. Overall virulence was quenched as demonstrated by the
lack of cytotoxic effects elicited by supernatants of cultures
treated with the extract. Importantly, using an in vivo model,
we have demonstrated efficacy in attenuating dermonecrosis, even
in the absence of adjuvant antibiotics.
This inhibition of virulence and pathogenesis was accomplished
without posing growth inhibitory pressures on not only S.
aureus, but also a panel of common members of the human
cutaneous microbiome. A robust skin microflora is critical to
skin barrier health and prevention of disease onset. The
majority of the bacterial cutaneous microbiome is represented by
Actinobacteria, Firmicutes, Proteobacteria and Bacteroidetes
[60]. Much like cases of dysbiosis in gut microflora,
broad-spectrum activity against the skin microflora also holds
the potential for fostering an environment amenable to the
proliferation of pathogenic bacteria [61]. The presence of
commensals, like Staphylococcus epidermidis, is essential to
state of host innate immunity [62]. Thus, it is noteworthy that
224C-F2 specifically blocks S. aureus virulence without adding
selective pressures on major representatives of the cutaneous
microbiome.
The mechanistic basis for 224C-F2’s quorum quenching activity
remain unclear. Multiple lines of evidence suggest that
components within 224C-F2 directly target the core machinery of
the agr system, such as our observation of agr P3 promoter
reduction (Fig 3) and reduced levels of d-toxin production (Fig
4), which is encoded within RNAIII transcript regulated by P3.
If 224C-F2 only targeted downstream factors regulated by quorum
sensing, such as a-hemolysin, inhibition of agr P3 or d-toxin
production would not have been expected. Potential targets
within the agr system include inhibition of AIP docking with
AgrC, prevention of AIP production through AgrB, or reduction of
AgrA activation (Fig 1). Future studies will seek to resolve the
mechanism, and this will be facilitated by the isolation of
individual active components for incorporation in
structure-activity relationship (SAR) studies.
We hypothesized that use of a complex mixture that targets an
indirect pathway to pathogen success (rather than direct
targeting for growth and survival) would be unlikely to result
the generation of resistant mutations. In fact, following 15
days of sequential passaging with 224C-F2 in vitro, no
resistance was detected. This is not surprising; recent findings
comparing individual natural products to complex botanical
compositions in other targets, such as multidrug-resistant
malaria, have demonstrated that single-compound drugs may not be
the best answer. For example, in the face of growing artemisinin
resistance for malaria, more chemically complex whole plant
therapies (Artemisia annua L., Asteraceae) have demonstrated
superior efficacy to the single compound in preventing drug
resistance [63]. Indeed, complex botanical compositions that
meet the FDA standards for safety and efficacy are eligible for
an alternative regulatory approval pathway as “botanical drugs”,
which are distinct from dietary supplements, and are
standardized to levels of marker compounds and regulated like
other single compound pharmaceuticals once approved [64]. Two
examples of successful botanical drugs include Veregen (Camellia
sinensis (L.) Kuntze, Theaceae, sinecatechin topical formulation
for anogenital warts) and Fulyzaq (Croton lechleri Müll. Arg.,
Euphorbiaceae, procyanidin and prodelphinidin oral formulation
for HIV/AIDS-related diarrhea).
While it is debatable whether virulence inhibitors will ever
serve as stand-alone therapeutics, many agree that their
application as adjuvants to existing lines of antibiotics could
be a critical tool in this era of rising antibiotic resistance.
Specifically, by inhibiting agr, such a therapy effectively
blocks the production of an entire suite of diverse
staphylococcal toxins, ranging from immune-attacking PSMs,
pore-forming hemolysins, and a number of other proteases and
lipases that damage the host tissue and weaken the host immune
response. This will be of particular relevance to patients faced
with toxin-mediated infection, including staphylococcal scalded
skin syndrome (esp. in neonates), abscesses, necrotizing
fasciitis, sepsis, atopic dermatitis (eczema) and more.
In conclusion, we have demonstrated that a folk-medical
treatment for skin inflammation and SSTIs that does not
demonstrate “typical” antibacterial activity (bacteriostatic or
bactericidal) nevertheless shows great potential for development
as a therapeutic due to its ability to specifically target and
quench S. aureus virulence. The results of this study are
important not only to future antibiotic discovery and
development efforts, but are also vital to the validation of
this previously poorly understood traditional medicine as an
efficacious therapy, and not simply an unsubstantiated relict of
folklore. Importantly, this composition was non-toxic to human
keratinocytes and no dermatopathology was noted upon
administration to murine skin. Moreover, the composition did not
inhibit growth of the normal skin microflora, suggesting that
its disruptive action on the cutaneous microbiome would be
minimal to nil. Future work will focus on evaluation of
individual actives within the composition with the aim of
determining whether a complex mixture, such as 224C-F2 or a
single compound will prove most effective against all agr
alleles and which will be least likely to develop resistance
when administered under multiple selective pressures, such as
for in vivo administration as an antibiotic adjuvant...
[ Excerpts ]
Botanical Extracts and Compounds from Schinus Plants
and Methods of Use
US2017007652
This disclosure relates to extracts from the Anacardiaceae
(cashew plant family) and compositions comprising compounds
contained therein. In certain embodiments, the extracts are
derived from the fruit of a Schinus plant. In certain
embodiments, the disclosure relates to methods of treating or
preventing bacterial infections, acne, and other related uses.
BACKGROUND
[0003] Since the widespread introduction of antibiotics in the
1940s, the same storyline has repeated itself over and over
again: new antibiotic is introduced and then resistant variants
emerge and quickly spread, effectively limiting the utility and
lifespan of the drug. Staphylococci are frequently the cause of
hospital infections such as infections from implanted medical
devices. Many staphylococcal strains have become resistant to
many modern day antibiotics. Improved therapies are needed.
[0004] One proposed strategy to overcome the problem of highly
virulent and resistant variants is to indirectly attack bacteria
by interfering with their means of communication, also known as
quorum sensing. Targeting microbial communication makes sense
because bacteria coordinate many of their virulence and
pathogenesis pathways through these systems. Quave et al.,
report quorum sensing inhibitors of Staphylococcus aureus from
botanical extracts. Planta Med. 2011, 77(02):188-95. See also
Quave & Horswill, Front Microbiol, 2014, 5:706.
[0005] Schinus terebinthifolia Raddi (synonym: Schinus
terebinthfolius) is a flowering plant in the family
Anacardiaceae, which can be found in Brazil, the Caribbean and
across the southern United States. It is considered an invasive
species in a number of countries. El-Massry et al. report
chemical compositions and antioxidant/antimicrobial activities
of various samples prepared from Schinus terebinthifolia leaves
cultivated in Egypt. J Agric Food Chem, 2009, 57:5265-5270.
Moura-Costa et al. report antimicrobial activity of plants used
as medicinals on an indigenous reserve in Rio das Cobras,
Parana, Brazil. J Ethnopharmacol, 2012, 143:631-638. Melo et al.
report alcohol extract of Schinu sterebinthifolia Raddi
(Aanacardiaceae) as a local antimicrobial agent in severe
autogenously fecal peritonitis in rats. Acta cirurgica
brasileira/Sociedade Brasileira para Desenvolvimento Pesquisa em
Cirurgia, 2014, 29 Suppl 1:52-56. See also Martius, Systema de
Materia Medica Vegetal Brasileira. Rio de Janeiro, 1854;
Moreira, Diccionario de Plantas Medicinaes Brasileiras. Rio de
Janeiro, 1862; Chernoviz, Formulario ou Guia Medica. 6 ed.
Paris, 1864; Burton, Viagens aos planaltos do Brasil—Tomo I: Do
Rio de Janeiro a Morro Velho, 1868
SUMMARY
[0007] This disclosure relates to extracts from the cashew
family of plants (Anacardiaceae) and compositions comprising one
or more compounds contained therein and related uses reported
herein. In certain embodiments, the extracts are derived from
the fruit of a Schinus plant such as Schinus terebinthifolia.
[0008] In certain embodiments, the disclosure relates to
extracts comprising a fruit derived mixture of compounds from a
Schinus plant wherein the extracting process comprises one or
more of the following steps of: mixing a fruit with an alcohol,
e.g., ethanol, methanol, or aqueous mixtures thereof
(ethanol:water or methanol:water, 50-95% alcohol, 80% methanol)
under conditions such that fruit compounds dissolves in the
methanol and removing the methanol providing a methanol derived
mixture of compounds; partitioning the methanol derived mixture
of compounds between hexane and water providing a water derived
mixture of compounds; partitioning the water derived mixture of
compounds between ethyl acetate and water providing a second
water derived mixture of compounds; partitioning the second
water derived mixture of compounds by mixing the second water
derived mixture of compounds with n-butanol under conditions
such that fruit compounds dissolve in the n-butanol and removing
the n-butanol providing an n-butanol derived mixture of
compounds; and purifying the n-butanol derived mixture of
compounds by liquid chromatography.
[0009] In certain embodiments, the extract comprises a mixture
of compounds having at least one component from each of the
following groups a) to d): a) a compound having a molecular
formula of C30H17O10; b) a compound having a molecular formula
of C30H21O10; c) a compound having a molecular formula of
C30H45O4; and d) a compound having a molecular formula of
C30H45O4.
[0010] In certain embodiments, this disclosure relates to
methods of treating or preventing bacterial infections or acne
comprising administering to a subject in need thereof or
contacting the skin of a subject in need thereof with a formula
comprising an extract or one or more compounds in an extract as
disclosed herein. In certain embodiments, the formula is
administered in combination with another antibiotic.
[0011] In certain embodiments, this disclosure relates to
methods of treating or preventing a toxin-mediated bacterial
infection comprising administering an effective amount of an
Schinus extract or compounds contained therein to a subject in
need thereof, including a subject at risk of, exhibiting
symptoms of, or diagnosed with a staphylococcal scalded skin
syndrome (esp. in neonates), abscesses, necrotizing fasciitis,
sepsis, or atopic dermatitis (eczema).
[0012] In certain embodiments, the subject is at risk of,
exhibiting symptoms of, or diagnosed with toxic shock syndrome,
scalded skin syndrome, abscesses, furuncles, cellulitis,
folliculitis, bloodstream infections, medical device infections,
pneumonia, osteomyelitis, staphylococcal food poisoning, skin
and soft tissue infections, endocarditis, eczema, atopic
dermatitis, psoriasis, impetigo, septic arthritis, brain
abscess, burn wounds, venous ulcers, diabetic foot ulcers,
surgical wounds, post-operation infections, carbuncles,
meningitis, bacteremia, necrotizing pneumonia, or necrotizing
fasciitis...
Extracts
and Compounds
[0072] In certain embodiments, an extract is made by the process
of extracting a mixture of compounds from the leaves, roots,
bark, stem, fruit, or branches of a Schinus plant such as
Schinus terebinthifolia. Other contemplated plants include:
Schinus andina and varieties (andina and subtridentata), Schinus
angustifolia, Schinus antiarthritica, Schinus areira, Schinus
bituminosa, Schinus bonplandiana, Schinus brasiliensis, Schinus
bumelioides, Schinus canrerae, Schinus chebataroffi, Schinus
chichita, Schinus crenata, Schinus dentata, Schinus dependens
and varieties (alfa, arenicola, brevifolia, crenata,
grandifolia, longifolia, obovata, ovata, paraguarensis,
parvifolia, patagonica, subintegra, tomentosa), Schinus
discolor, Schinus diversifolia, Schinus engleri and varieties
(engleri, uruguayensis), Schinus fagara, Schinus fasciculate and
varieties (arenaria, arenicola, boliviensis, fasciculata),
Schinus ferox, Schinus gracilipes and varieties (gracilipies,
pilosus), Schinus huigan, Schinus huyngan and varieties
(heterophyllus, longifolius, obovatus, subtridentata, undulate),
Schinus indicus, Schinus johnstonii, Schinus latifolius and
varieties (tomentosus), Schinus lentiscifolius and varieties
(angustifolia, flexuosa, subobtusa), Schinus leucocarpus,
Schinus limonia, Schinus longifolia and varieties (longifolia,
paraguarensis), Schinus marchandii, Schinus maurioides, Schinus
mellisii, Schinus meyeri, Schinus microphylla, Schinus
microphyllus, Schinus molle and varieties (areira,
argentifolius, hassleri, huigan, huyngan, molle, rusbyi),
Schinus molleoides, Schinus montanus and varieties (crenuloides,
patagonicus), Schinus mucronulatus, Schinus myricoides, Schinus
myrtifolia, Schinus occidentalis, Schinus odonellii, Schinus
paraguarensis, Schinus patagonicus and varieties (crenuloides,
patagonicus), Schinus pearcei, Schinus pilifera and varieties
(boliviensis, cabrerae, pilifer), Schinus polygama and varieties
(australis, chubutensis, crenata, fasciculata, heterophylla,
ovata, parviflora, patagonica), Schinus polygamus, Schinus
praecox, Schinus pubescens, Schinus ramboi, Schinus resinosus,
Schinus rhoifolia, Schinus roigii, Schinus sinuatus, Schinus
spinosus, Schinus tenuifolius, Schinus terebinthifolius and
varieties (acutifolia, damaziana, glaziovana, pohlianus,
raddiana, rhoifolia, selloana, terebinthifolia, ternifolia),
Schinus terebinthifolius, Schinus ternifolia, Schinus tomentosa,
Schinus tragodes, Schinus velutinus, Schinus venturii, Schinus
weinmannifolius and varieties (angustifolius, dubius,
glabrescens, hassleri, intermedius, pauciflorus, paucijuga,
pubescens, riedelianus, ridelianus, weinmannifolius) and hybrids
thereof.
[0073] In certain embodiments, the extracting process comprises
the step of mixing the fruit from the plant with a polar
solvent, such as a liquid comprising methanol, ethanol, ethyl
acetate, n-butanol, acetonitrile, acetone, methylene chloride or
chloroform, under conditions such that a mixture of compounds in
the fruit dissolves in the solvent. In certain embodiments, the
process further comprises the step of removing the solvent by
evaporation from the mixture of compounds. In certain
embodiments, the process further comprises the step of purifying
the mixture of compounds by liquid chromatography through a
solid absorbent, e.g., wherein the solid absorbent comprises
silica gel or alumina...
[0078] In certain embodiments, methods of extraction comprise
mixing the fruit of a Schinus plant with an water miscible
carbon containing solvent, e.g., such as a protic solvent, an
alcohol, methanol, ethanol, 1-propanol, 2-propanol,
tetrahydrofuran, acetone, acetic acid, 1,4-dioxane or mixture
providing a concentrate with a mixture of compounds and
substantially removing the solvent from the concentrate,
purifying the solvent derived concentrate to less than 5%, 1%,
or 0.5% by weight of the solvent used in the extraction, e.g.,
evaporating the protic solvent and/or optionally in combination
with mixing the concentrate with water, sonicating the water,
freezing the water to provide ice, and removing the ice by
sublimation (e.g. in a vacuum of low pressure) wherein said
purification methods may be repeated in combination. In certain
embodiments, the method further comprises suspending the solvent
derived concentrate in water and optionally extract impurities
in a hydrocarbon solvent such as cyclohexane, heptane, hexane,
pentane, 2,2,4-trimethylpentane, separating the hydrocarbon from
the water providing a water layer. In certain embodiments, the
method further comprises mixing the water layer with a solvent
that is immiscible in water (polar and/or aprotic), e.g., such
as ethyl acetate, diethyl ether, methyl tertbutyl ether,
n-butanol, toluene, methylene chloride, carbon tetrachloride,
1,2-dichloroethant, and/or chloroform, and purifying the solvent
to provide a second solvent derived concentrate. In further
embodiments, the second derived concentrate is purified one or
more times by liquid chromatography, e.g., normal phase
chromatography...
EXAMPLES
Collection of Plant Material
[0161] Schinus terebinthifolia Raddi, Anacardiaceae leaves,
stems, and fruits were collected in bulk from private lands in
DeSoto County, Fla. in November of 2013 and 2014 after obtaining
permission from the land owner. Procedures from the 2003 WHO
Guidelines for good agricultural and collection practices (GACP)
for medicinal plants were followed for the collection and
identification of bulk and voucher specimens, specifically
excluding any populations that may have prior exposure to
herbicides. Vouchers were deposited at the Emory University
Herbarium (GEO) (Voucher CQ-400, GEO Accession No. 020063) and
were identified using the standard Flora for Florida. Plant
leaves, stems, and fruits were separated and manually cleaned of
soil and contaminants. Plant material was then dried in a
desiccating cabinet at low heat. Once dry, plant material was
sealed in paper bags and stored at room temperature until
further processing.
Extraction and Separation.
[0162] Crude methanol extracts of fruits were created by
blending a ratio of 1 g dry material:10 mL MeOH into a slurry in
a Waring commercial blender for 5 min, and sonicating the
material for 20 minutes. Following decantation of the extract,
plant material was subjected to two more rounds of sonication
followed by filtration. Filtered extracts were combined,
concentrated at reduced pressure with rotary evaporators
(<40° C.), and lyophilized. The dried extract was resuspended
in 1:5 MeOH:H2O at 1 g:31 mL and underwent sequential
liquid-liquid partitioning three times each with an equal volume
of hexane, EtOAc, and H2O saturated n-butanol. The organic
partitions were dried over Na2SO4 and filtered. Each partition
was concentrated in vacuo at <40° C. The hexane partition was
dissolved and transferred to a tared scintillation vial and
dried under forced air to yield 430B. The remaining partitions
were suspended in dH2O, shell frozen, lyophilized and stored at
−20° C. The EtOAc partition was labeled 430C, the n-butanol
430D, and final remaining aqueous partition 430E...
[ Excerpts ]
Botanical
Extracts and Compounds from Castanea Plants and Methods of
Use
US2016375074
This disclosure relates to extracts from chestnut plants and
compositions comprising compounds contained therein. In certain
embodiments, the extracts are derived from the leaves of a
Castanea plant. In certain embodiments, the disclosure relates
to methods of treating or preventing bacterial infections, acne,
and other related uses...
BACKGROUND
[0003] Since the widespread introduction of antibiotics in the
1940s, the same storyline has repeated itself over and over
again: new antibiotic is introduced and then resistant variants
emerge and quickly spread, effectively limiting the utility and
lifespan of the drug. From an evolutionary biology perspective,
this is not surprising; indeed, resistant mutants are expected
to arise when any lifeform with the ability to rapidly reproduce
and mutate is faced with a direct selective pressure, especially
when a single drug is used against a single target.
Staphylococci are frequently the cause of hospital infections
such as infections from implanted medical devices. Many
Staphylococci strains have become resistant to many modern day
antibiotics. Improved therapies are needed.
[0004] One proposed strategy to overcome the problem of
resistant variants is to indirectly attack bacteria by
interfering with their means of communication, also known as
quorum sensing. Targeting microbial communication makes sense
because bacteria coordinate many of their virulence and
pathogenesis pathways through these systems. Quave et al.,
report quorum sensing inhibitors of Staphylococcus aureus from
botanical extracts. Planta Med. 2011, 77(02):188-95.
[0005] Castanea sativa (chestnut) is a flowering plant in the
family Fagaceae which can be found in Europe. See Braga et al.,
Nat Prod Res., 2015, 29(1):1-18. Almeida et al. report in vivo
skin irritation potential of a Castanea sativa (Chestnut) leaf
extract. Basic & Clinical Pharmacol Toxicol, 2008,
103(5):461-7. See also Almeida et al. J Photochem Photobiol B:
Biol, 2015, 144(0):28-34. Henry et al. report cosmetic
compositions containing an extract of leaves of the Castanea
sativa plant and cosmetic treatments. U.S. Pat. No. 8,067,044
(2011).
[0006] Garo et al., report asiatic acid and corosolic acid
enhance the susceptibility of Pseudomonas aeruginosa biofilms to
tobramycin. Antimicrob Agents Chemother, 2007, 51(5):1813-7. See
also Rangasamy et al. South African J Botany, 2014, 93:198-203.
[0007] Wong et al. report aqueous methanolic extracts of
Melastoma malabathricum L. exhibited antibacterial activity. Nat
Prod Res, 2012,26(7):609-18
[0008] Perioni et al. report a survey on the natural ingredients
used in folk cosmetics, cosmeceuticals and remedies for healing
skin diseases. J Ethnopharmacol, 2004, 91(2-3):331-44.
[0009] References cited herein are not an admission of prior
art.
SUMMARY
[0010] This disclosure relates to extracts from chestnut plants
and compositions comprising one or more compounds contained
therein and related uses reported herein. In certain
embodiments, the extracts are derived from the leaves of a
Castanea plant such as Castanea sativa.
[0011] In certain embodiments, the disclosure relates to
extracts comprising a leaf derived mixture of compounds from a
Castanea plant wherein the extracting process comprises one or
more of the following steps of: mixing a leaf with methanol
under conditions such that leaf compounds dissolves in the
methanol and removing the methanol providing a methanol derived
mixture of compounds; partitioning the methanol derived mixture
of compounds in hexane and water providing a water derived
mixture of compounds; partitioning the water derived mixture of
compounds by mixing the water with ethyl acetate under
conditions such that leaf compounds dissolve in the ethyl
acetate and removing the ethyl acetate providing an ethyl
acetate derived mixture of compounds; and purifying the ethyl
acetate derived mixture of compounds by liquid chromatography
through silica with a mobile phase comprising hexane and ethyl
acetate; wherein the mobile phase comprises increasing amounts
of ethyl acetate, and a mobile phase fraction is isolated
comprising a leaf derived mixture of compounds which does not
contain chlorogenic acid, ellagic acid, hyperoside,
isoquercitrin, or rutin.
[0012] In certain embodiments, this disclosure relates to
methods of treating or preventing a bacterial infections or acne
comprising administering to a subject in need thereof or
contacting the skin of a subject in need thereof with a formula
comprising an extract or one or more compounds in an extract as
disclosed herein. In certain embodiments, the formula is
administered in combination with another antibiotic...
Chestnut Leaf Extracts Block Staphylococcus aureus Virulence and
Pathogenesis
[0063] Quorum quenching activity has been discovered in the
natural products extracted from Castanea sativa leaves. The
extract is able to attenuate virulence by quenching S. aureus
agr-mediated quorum sensing, effectively blocking production of
harmful exotoxins at sub-inhibitory concentrations for growth.
Experiments indicate a lack of cytotoxicity to human skin cells,
lack of growth inhibitory activity against the normal skin
microflora, lack of resistance development, and efficacy in a
skin abscess animal model.
[0064] Staphylococcus aureus is an abundant, opportunistic
pathogen that is the causative agent of numerous infections. Due
to its prevalence as a leading cause of healthcare-associated
infection, and its highly multidrug resistant nature, S. aureus
is a serious threat. It colonizes the nasal passages of
approximately 30% of the healthy adult population. S. aureus
infections initiate through trauma to the skin or mucosal layer
and then progress through an invasive or toxin-mediated process.
The prevalence of these infections has increased due to higher
rates of immunosuppressive conditions, greater use of surgical
implants, and dramatic increases in antibiotic resistance.
[0065] S. aureus produces an extensive array of enzymes,
hemolysins, and toxins that are important to its ability to
spread through tissues and cause disease. These virulence
factors serve a wide scope of purposes in the infection process,
including disruption of the epithelial barrier, inhibition of
opsonization by antibody and complement, neutrophil cytolysis,
interference with neutrophil chemotaxis, and inactivation of
antimicrobial peptides. The expression of all of these invasive
factors is controlled by cell-density quorum sensing using the
autoinducing peptide (AIP) molecule. Like other quorum-sensing
signals, AIP accumulates outside the cell until it reaches a
critical concentration and then binds to a surface receptor
called AgrC, initiating a regulatory cascade. Since AIP controls
the expression of accessory factors for S. aureus, this
regulatory system has been named the accessory gene regulator
(agr), and the majority of the proteins necessary for this
quorum-sensing system to function are encoded in the agr
chromosomal locus. Applying inhibitors to quench this
communication system to attenuate pathogenicity and virulence
lies at the core of the quorum quenching approach...
Extracts and Compounds
[0086] In certain embodiments, an extract is made by the process
of extracting a mixture of compounds from the leaves, roots,
bark, stem, or branches of a Castanea plant e.g., Castanea
sativa. Other contemplated plants include: Castanea
acuminatissima, Castanea alabamensis, Castanea alnifolia,
Castanea americana, Castanea argentea, Castanea argyrophylla,
Castanea arkansana, Castanea armata, Castanea ashei, Castanea
blaringhemii, Castanea bodinieri, Castanea brevicuspis, Castanea
bungeana, Castanea burbankii, Castanea buruana, Castanea
californica, Castanea Castanea, Castanea castanicarpa, Castanea
castenea var. pubinervis, Castanea chincapin, Castanea
chinensis, Castanea chrysophylla, Castanea concinna, Castanea
cooperta, Castanea costata, Castanea coudersii, Castanea
crenata, Castanea davidii, Castanea dentata, Castanea
diversifolia, Castanea dovaricata, Castanea duclouxii, Castanea
echidnocarpa, Castanea edonii, Castanea edwii, Castanea
endicottii, Castanea eonii, Castanea fagus, Castanea falconeri,
Castanea fargesii, Castanea fauriei, Castanea fleetii, Castanea
floridana, Castanea formosana, Castanea furfurella, Castanea
glomerata, Castanea henryi, Castanea henryi, Castanea
hupehensis, Castanea hystrix, Castanea, Castanea inermis,
Castanea japonica, Castanea javanica, Castanea kusakuri,
Castanea lanceifolia, Castanea latifolia, Castanea margaretta,
Castanea martabanica, Castanea microcarpa, Castanea mollissima,
Castanea montana, Castanea morrisii, Castanea nana, Castanea
neglecta, Castanea ozarkensis, Castanea paucispina, Castanea
phansipanensis, Castanea prolifera, Castanea pubinervis,
Castanea pulchella, Castanea pumila, Castanea purpurella,
Castanea regia, Castanea rhamnifolia, Castanea rockii, Castanea
roxburghii, Castanea seguinii, Castanea sempervirens, Castanea
sessilifolia, Castanea sinensis, Castanea sloanea, Castanea
spectabilis, Castanea sphaeroarpa, Castanea sphaerocarpa,
Castanea stricta, Castanea sumatrana, Castanea tribuloides,
Castanea tungurrut, Castanea vesca, Castanea vilmoriniana,
Castanea vulgaris, Castanea wattii and hybrids thereof.
[0087] In certain embodiments, the extracting process comprises
the step of mixing the leaf from the plant with a polar solvent,
such as a liquid comprising methanol, ethanol, ethyl acetate,
acetonitrile, acetone, methylene chloride or chloroform, under
conditions such that a mixture of compounds in the leaf
dissolves in the solvent. In certain embodiments, the process
further comprises the step of removing the solvent by
evaporation from the mixture of compounds. In certain
embodiments, the process further comprises the step of purifying
the mixture of compounds by liquid chromatography through a
solid absorbent, e.g., wherein the solid absorbent comprises
silica gel or alumina.
[0088] In certain embodiments, the disclosure relates to
extracts comprising a leaf derived mixture of compounds from a
Castanea plant wherein the extracting process comprises the
steps of: mixing a leaf with methanol under conditions such that
leaf compounds dissolves in the methanol and removing the
methanol providing a methanol derived mixture of compounds;
partitioning the methanol derived mixture of compounds in hexane
and water providing a water derived mixture of compounds;
partitioning the water derived mixture of compounds by mixing
the water with ethyl acetate under conditions such that leaf
compounds dissolve in the ethyl acetate and removing the ethyl
acetate providing an ethyl acetate derived mixture of compounds;
and purifying the ethyl acetate derived mixture of compounds by
liquid chromatography through silica with a mobile phase
comprising hexane and ethylene acetate; wherein the mobile phase
comprises increasing amounts of ethyl acetate, and a mobile
phase fraction is isolated comprising a leaf derived mixture of
compounds which does not contain chlorogenic acid, ellagic acid,
hyperoside, isoquercitrin, or rutin...
[0089] Chromatography refers to the separation of a mixture of
compounds dissolved in a fluid called the mobile phase, which
carries the compounds through a structure holding another
material called the stationary phase. The various compounds or
components of the mixture travel at different speeds, causing
them to separate. The separation is based on differential
partitioning between the mobile and stationary phases. Subtle
differences in a partition coefficient of each compound result
in differential retention on the stationary phase and thus
changing the separation.
[0090] In normal-phase chromatography, the stationary phase is
polar. In reversed phase, the stationary phase is nonpolar.
Typical stationary phases for normal-phase chromatography are
silica or organic moieties with cyano and amino functional
groups. For reversed phase, alkyl hydrocarbons are the preferred
stationary phase. Examples are solid supports containing a
surface conjugated with a hydrocarbon chain, e.g., octadecyl
(C18), octyl (C8), and butyl (C4).
[0091] In normal-phase chromatography, the least polar compounds
elute first and the most polar compounds elute last. The mobile
phase typically consists of a nonpolar solvent such as hexane or
heptane mixed with a slightly more polar solvent such as
isopropanol, ethyl acetate or chloroform. Retention to the
stationary phase decreases as the amount of polar solvent in the
mobile phase increases. In reversed phase chromatography, the
most polar compounds elute first with the most nonpolar
compounds eluting last. The mobile phase is generally a binary
mixture of water and a miscible polar organic solvent like
methanol, acetonitrile or THF.
[0092] In certain embodiments, methods of extraction comprise
mixing leaves of a Castanea plant with an water miscible carbon
containing solvent, e.g., such as a protic solvent, an alcohol,
methanol, ethanol, 1-propanol, 2-propanol, tetrahydrofuran,
acetone, acetic acid, 1,4-dioxane or mixture providing a
concentrate with a mixture of compounds and substantially
removing the solvent from the concentrate, purifying the solvent
derived concentrate to less than 5%, 1%, or 0.5% by weight of
the solvent used in the extraction, e.g., evaporating the protic
solvent and/or optionally in combination with mixing the
concentrate with water, sonicating the water, freezing the water
to provide ice, and removing the ice by sublimation (e.g. in a
vacuum of low pressure) wherein said purification methods may be
repeated in combination. In certain embodiments, the method
further comprises suspending the solvent derived concentrate in
water and optionally extract impurities in a hydrocarbon solvent
such as cyclohexane, heptane, hexane, pentane,
2,2,4-trimethylpentane, separating the hydrocarbon from the
water providing a water layer. In certain embodiments, the
method further comprises mixing the water layer with a solvent
that is immiscible in water (polar and/or aprotic), e.g., such
as ethyl acetate, diethyl ether, methyl tertbutyl ether,
toluene, methylene chloride, carbon tetrachloride, 1,2-di chl
oroethant, and/or chloroform, and purifying the solvent to
provide a second solvent derived concentrate. In further
embodiments, the second derived concentrate is purified one or
more times by liquid chromatography, e.g., normal phase
chromatography. Typically the solid absorbent is polar such as
silica. In certain embodiments, the extract is a portion
isolated after the column solvent is more than 50% ethyl acetate
in hexane...
Extraction and Purification of QSI-containing Fractions
[0181] Crude methanol extracts (Extract 224) of the ground
leaves were created by maceration of the plant materials at room
temperature using a ratio of 1 g dry leaves: 10 mL MeOH for two
successive periods of 72 hours, with daily agitation. Filtered
extracts were combined, concentrated at reduced pressure and a
temperature<40° C. with rotary evaporators, and lyophilized
before being re-suspended in water and partitioned in succession
with hexane, ethyl acetate and butanol. The resulting
non-aqueous partitions were dried over anhydrous Na2SO4,
concentrated in vacuo, and lyophilized before testing for
activity.
[0182] The most active partition (ethyl acetate, extract 224C)
was subjected to further fractionation using a CombiFlash® Rf+
(Teledyne ISCO) flash chromatography system using a RediSep Rf
Gold silica column. Extract 224C was bonded to Celite 545 (Acros
Organics) at a 1:4 ratio and dry-loaded using a RediSep dry load
cartridge. The mobile phase consisted of (A) hexane, (B) EtOAc,
and (C) MeOH. The linear gradient begins with 100% A for 6.3
column volumes (CV), then 50:50 A:B at 25.3 CV, to 100% B at
63.3 CV, which is held till 69.6 CV, then to 70:30 B:C at 88.6
CV which is held till 94.9 CV. The chromatography was monitored
at 254 and 280 nm, as well as via ELSD. The resulting fractions
were combined into 5 fractions. Following further bioassay
testing, it was determined that the fraction which eluted from
30-40 CV (224C-F2) was most active. The full extract
fractionation scheme is presented in FIG. 2...
[ Excerpts ]
ANTI-BIOFILM
COMPOSITIONS AND METHODS FOR USING
US2012088671
FIELD OF THE
INVENTION
[0002] The present invention generally relates to biofilms. In
particular, it relates to compositions and methods for
inhibiting biofilm formation and/or reducing the growth of an
established biofilm.
BACKGROUND
OF THE INVENTION
[0003] Staphylococcus aureus is arguably the most problematic
pathogen faced by modern healthcare systems today, owing in
large part to the persistent emergence of antibiotic resistant
strains. This is perhaps most evident in the recent appearance
of methicillin-resistant strains even among isolates causing
community-acquired infection. Moreover, many of these strains,
most notably those of the USA300 clonal lineage, have the
capacity to cause serious, life-threatening infection even in
otherwise healthy individuals. This accounts in large part for
the observation that, in the United States alone in 2005, an
estimated 94,360 patients suffered from invasive infection
caused by methicillin-resistant S. aureus (MRSA), with
approximately 18,650 resulting in a fatal outcome.
[0004] The continued emergence of antibiotic-resistant strains
has created an urgent need for new antimicrobial agents.
However, many S. aureus infections are recalcitrant to
antimicrobials even in the absence of issues related to acquired
resistance. A primary contributing factor to this recalcitrance
is formation of a biofilm on both native tissues and indwelling
medical devices. This is due to the fact that the biofilm
confers a degree of intrinsic resistance that often necessitates
surgical intervention to debride infected tissues and/or remove
infected devices. For example, one study found that nearly half
of patients with implanted orthopedic devices admitted to a
hospital with S. aureus bacteremia had developed an
implant-associated infection. Thus, while there is an urgent
need for new antibiotics, there is an equally urgent need to
develop therapeutic agents that could be used to limit biofilm
formation. While such agents would not necessarily function as
antibiotics in and of themselves, they could be used as a
prophylactic to limit biofilm formation (e.g. coating for
implanted devices, surgical lavage, or pre-operative oral
prophylaxis) or as a therapeutic to be used in conjunction with
more conventional antibiotics to treat an established
biofilm-associated infection.
SUMMARY OF
THE INVENTION
[0005] Among the various aspects of the present disclosure is
the provision of a polyphenolic composition. The polyphenolic
composition is prepared by a process comprising (a) partitioning
an alcohol extract of a plant with a mixture of water and hexane
to form a first water partition and a hexane partition; (b)
partitioning the first water partition with a mixture of water
and ethyl acetate to form a second water partition and a ethyl
acetate partition; (c) partitioning the second water partition
with a mixture of water and butanol to form a third water
partition and a butanol partition; and (d) fractionating the
butanol partition by column chromatography with a mobile phase
comprising a mixture of methanol and dichloromethane, wherein
the polyphenolic composition is eluted by the mobile phase in
which the volume ratio of methanol to dichloromethane is about
40:60.
[0006] Another aspect of the disclosure provides a combination
comprising at least one phenolic phytochemical and at least one
antimicrobial agent.
[0007] Still another aspect of the disclosure encompasses a
method for inhibiting formation of a biofilm. The method
comprises contacting a plurality of free floating microorganisms
with the polyphenolic composition detailed above or a fraction
thereof such that formation of the biofilm is inhibited.
[0008] A further aspect of the disclosure provides a method for
inhibiting growth of an established biofilm. The method
comprises contacting the biofilm with at least one phenolic
phytochemical and at least one antimicrobial agent such that the
biofilm has a reduced number of microorganisms.
[0009] Other features and iterations of the invention are
described in more detail below...
DETAILED
DESCRIPTION OF THE INVENTION
[0023] The present invention provides compositions and methods
for inhibiting the formation and growth of biofilms. In one
aspect, the disclosure provides a polyphenolic composition
comprising ellagic acid and ellagic acid derivatives. The
phenolic composition is derived from a plant extract by a
process disclosed herein. It has been discovered that the
polyphenolic composition inhibits biofilm formation and
increases susceptibility of an established biofilm to
antimicrobial agents. Another aspect of the disclosure provides
a combination comprising at least one phenolic phytochemical and
at least one antimicrobial agent, wherein the combination
inhibits the growth of established biofilms. Advantageously, the
activity of the combination disclosed herein is synergistic,
i.e., its activity is more than the sum of the activity of each
individual component. Also provided herein are methods for
inhibiting the formation of a biofilm, as well as methods
inhibiting the growth of an established biofilm.
[0024] (I) Polyphenolic Composition
[0025] In one embodiment a polyphenolic composition is provided.
The polyphenolic composition is prepared by a process comprising
(a) partitioning an alcohol extract of a plant with a mixture of
water and hexane to form a first water partition and a hexane
partition; (b) partitioning the first water partition with a
mixture of water and ethyl acetate to form a second water
partition and a ethyl acetate partition; (c) partitioning the
second water partition with a mixture of water and butanol to
form a third water partition and a butanol partition; and (d)
fractionating the butanol partition by column chromatography
with a mobile phase comprising a mixture of methanol and
dichloromethane, wherein the polyphenolic composition is eluted
by the mobile phase in which the volume ratio of methanol to
dichloromethane is about 40:60.
[0026] The method comprises a series of steps such that a
fraction enriched with a polyphenolic composition may be
isolated from an alcohol extract of a plant.
(a) Alcohol Extract
[0028] The alcohol extract may be derived from a plant belonging
to a variety of plant families. Non-limiting examples of
suitable plant families include Rosaceae, Fagaceae, Salicaceae,
Myrtaceae, Vitaceae, Ericaceae, Combretaceae, Elaeocarpaceae,
Lythraceae, Symplocaceae, Hypoxidaceae, Amaranthaceae,
Juncaceae, Juglandaceae, Sapindaceae, Lamiaceae, Magnoliaceae,
Gentianaceae, Apocynaceae, Moringaceae, Apiaceae, Rutaceae,
Aquafoliaceae, Santalaceae, Cornaceae, Asteraceae, Bignoniaceae,
and Fabaceae. Preferred plant families include Rosaceae,
Fagaceae, Salicaceae, Myrtaceae, Vitaceae, Ericaceae,
Combretaceae, and Juglandaceae. In some embodiments, the plant
may be Castanea sativa, Quercus cerris, Juglans regia, Vitis
vinefera, Crataegus monogyna, Prunus spinosa, Rosa canina, or
Rubus ulmifolius. In some embodiments, the plant family may be
Rosaceae. In an exemplary embodiment, the plant may be Rubus
ulmifolius.
[0029] A variety of plant parts may be used to arrive at the
alcohol extract. Suitable plant parts include roots, bulbs,
tubers, leaves, basal leaves, stems, stem nodes, stem
internodes, galls, stalks, woody parts, flowers, inflorescences,
fruits, infructescences, seeds, and combinations thereof. The
plant part may be fresh, dried, frozen, or lyophilized. The
plant part may be ground or pulverized into a plant material
using a homogenizer, a blender, a mortar and pestle, a
sonicator, or a similar apparatus.
[0030] The plant extract typically is prepared by contacting the
plant material with an alcohol solvent for an appropriate period
of time. Non-limiting examples of suitable alcohol solvents
include methanol, ethanol, propanol, butanol, or combinations
thereof. In preferred embodiments, the solvent may be ethanol
such that the alcohol extract is an ethanol extract. The
concentration of alcohol that is contacted with the plant
material may range from about 1% to about 100%. In embodiments
in which ethanol is the solvent, the concentration of ethanol
may range from about 1% to about 20%, from about 20% to about
40%, from about 40% to about 60%, from about 60% to about 80%,
or from about 80% to about 100%. In an exemplary embodiment, the
concentration of ethanol may be about 95%.
[0031] The period of time the plant material is contacted with
the alcohol solvent may range from about 1 hour to about 5 days.
In various embodiments, the plant material may be contacted with
the alcohol solvent for about 1-24 hours, for about 24-48 hrs,
for about 48-72 hours, for about 72-96 hours, or for about
96-120 hours. In an exemplary embodiment, the period of time the
plant material is contacted with the alcohol solvent may be
about 72 hours: Upon removal of the extract from the plant
material, the plant material may be extracted one or more
additional times with fresh alcohol solvent, essentially as
detailed above.
[0032] The alcohol solvent may be removed from the plant alcohol
extract to form a dry plant alcohol extract. Those of skill in
the art are familiar with suitable techniques to remove the
alcohol solvent including, without limit, evaporation,
distillation, and lyophillization.
(b) Liquid Extractions
[0034] The process for preparing a fraction rich in the
polyphenolic compounds comprises subjecting the plant alcohol
extract to a series of liquid extractions such that the
polyphenolic compounds are partitioned into one of the phases
and the other compounds are partitioned into the other phase. In
general, the series of liquid extractions comprises contacting
the plant alcohol extract (or partition thereof) with a solvent
system, wherein the polarity of one or more of the solvents
changes during each successive series of extractions. Those of
skill in the art are familiar with liquid extraction protocols
and suitable solvent systems. Generally, the liquids are mixed
by gentle inversion at room temperature. After separation of the
phases, the phase containing the polyphenolic compounds thereof
may be extracted one or more times with the solvents of
interest.
[0035] For example, the first step of the process may comprise a
liquid extraction during which the plant alcohol extract is
partitioned in a mixture of water and an alkane to form a first
water partition and an alkane partition. Typically, the
polyphenolic compounds are partitioned into the water phase upon
extraction with a mixture of water and alkane. The alkane
typically will comprise from five to ten carbons, and may be
linear or branched. Suitable alkanes include, without limit,
pentane, hexane, heptane, octane, and combinations thereof. An
exemplary alkane is hexane.
[0036] In the next step of the process, for example, the first
water partition may be extracted in a mixture of water and a
non-polar solvent to form a second water partition and a
non-polar solvent partition. Generally, the polyphenolic
compounds are partitioned into the water phase upon extraction
with a mixture of water and non-polar solvent. In various
embodiments, the non-polar solvent may be ethyl acetate, butyl
acetate, chloroform, diethyl ether, or combinations thereof. An
exemplary non-polar solvent is ethyl acetate.
[0037] The next and final extraction step, for example, may
comprise extracting the second water partition with a mixture of
water and an alcohol to form a third water partition and an
alcohol partition. Typically, the polyphenolic compounds are
partitioned into the alcohol phase upon extraction with a
mixture of water and alcohol. The alcohol may comprise from one
to ten carbons, and may be linear or branched. Non-limiting
examples of suitable alcohols include methanol, ethanol,
propanol, isopropanol, butanol, pentanol, hexanol, and heptanol.
An exemplary alcohol is butanol.
[0038] In a preferred embodiment, the first liquid-liquid
extraction comprises water and hexane, the second liquid-liquid
extraction comprises water and etliyl acetate, and the third
liquid-liquid extraction comprises water and butanol.
(c) Column Chromatography
[0040] The method may further comprise fractionating the
polyphenolic-rich fraction by column chromatography. Typically,
the column will comprise an inorganic stationary phase.
Non-limiting examples of suitable inorganic stationary phase
materials include silica-based materials, silica gel, magnetic
silica particles, glass powder, diatomaceous earth, zeolites,
aluminium oxides, silicon oxides, titanium oxides, zirconium
oxides, and hydroxyapatite. In an exemplary embodiment, the
column chromatography comprises a silica gel stationary phase.
[0041] The mobile phase may comprise a mixture of methanol and
dichloromethane. Those of skill in the art will appreciate that
other mobile phases may be used to separate the polyphenolic
composition from the other compounds. In embodiments in which
the mobile phase comprises methanol and dichloromethane, the
concentration of dichloromethane in the mobile phase typically
decreases during the fractionation while the concentration of
methanol in the mobile phase increases during the fractionation.
The phenolic-rich fraction generally elutes from the column with
a volume ratio of methanol to dichloromethane from about 30:70
to about 70:30. For example, the volume ratio of methanol to
dichloromethane that elutes a phenolic-rich fraction may range
from about 30:70, 32.5:67.5. 35:65, 37.5:62.5, 40:60, 42.5:57.5,
45:55, 47.5:52.5, 50:50, 52.5:47.5, 55:45, 57.5:42.5, 60:40,
62.5:37.5, 65:35, 67.5:32.5, or 70:30. In preferred embodiments,
the polyphenolic-rich fraction may elute from the column at a
volume ratio of methanol to dichloromethane of about 40:60,
50:50, or 60:40. In an exemplary embodiment, the
polyphenolic-rich fraction may elute from the column at a volume
ratio of methanol to dichloromethane of about 40:60. The
polyphenolic-rich fraction may be dried by removing the mobile
phase solvents using standard procedures...
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