Chestnut Leaf Extract Disarms Deadly Staph Bacteria
Leaves of the European chestnut tree contain ingredients with the power to disarm dangerous staph bacteria without boosting its drug resistance, scientists at Emory University in Atlanta have found. The study was published in August 2015 in PLOS ONE. The team reports that a chestnut leaf extract, rich in ursene and oleanene derivatives, blocks Staphlococcus aureus virulence and pathogenesis without detectable resistance.
A release from the university explains that the use of chestnut leaves in traditional folk remedies inspired the research, led by Cassandra Quave, an ethnobotanist at Emory.
The release quotes Quave as saying, “We’ve identified a family of compounds from this plant that have an interesting medicinal mechanism. 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.