Chestnut leaves have been a critical ingredient in many folk remedies to treat skin infections. This has inspired new research by Cassandra Quave, an ethnobotanist at Emory University. Amazingly, she found that chestnut leaves work by stripping Staphlococcus aureus` ability to create toxins that cause damage to the tissues, rather than by killing staph.
“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.”
According to the Centers for Disease Control and Prevention, antibiotic-resistant bacteria cause at least 2 million illnesses and 23,000 deaths in the U.S every year. Given that chestnut leaf extract is capable of blocking Staphlococcus aureus virulence and pathogenesis without antibiotic resistance, it holds a great potential in both preventing and treating infections of methicillin-resistant S. aureus, or MRSA. This means that ” the extract doesn’t disturb the normal, healthy bacteria on human skin. It’s all about restoring balance.”
Quave and her colleagues have studied the folk remedies of rural people in Southern Italy for years and were told how the people would make a tea from these leaves and wash their skin with the solution to treat inflammation and skin infections.
For the aim of this study, Quave teamed up with Alexander Horswill, a microbiologist at the University of Iowa. His lab is focused on creating tools for use in drug recovery, like glow-in-the-dark staph strains.
Quave and Horswill steeped the 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.”
They produced an extracts containing 94 chemicals, out of which ursene and oleanene are the most active. It was found that this powerful extract blocks staph`s ability to communicate with one another, which is known as quorum sensing.
“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 preventative coatings for medical devices and coatings like tampons that provide favorable conditions for growth of MRSA, as treatment for MRSA infections, and a preventative spray for football pads.