Natural compound found in plants inhibits deadly fungi

Carol Clark

“It’s a really bad bug,” says Lewis Marquez, first author of the study. “Between 30 to 60% of the people who get infected with C. auris end up dying.”

Global threat

A new study finds that a natural compound found in many plants inhibits the growth of drug-resistant Candida fungi — including its most virulent species, Candida auris, an emerging global health threat. C. auris is often multidrug-resistant and has a high mortality rate, leading the Centers for Disease Control and Prevention (CDC) to label it a serious global health threat.

Infections

Candida is a yeast often found on the skin and in the digestive tract of healthy people. Some species, such as Candida albicans, occasionally grow out of control and cause mild infections in people.

In more serious cases, Candida can invade deep into the body and cause infections in the bloodstream or organs such as the kidney, heart or brain. Immunocompromised people, including many hospital patients, are most at risk for invasive Candida infections, which are rapidly evolving drug resistance.

In 2007, the new Candida species, C. auris, emerged in a hospital patient in Japan. Since then, C. auris has caused health care-associated outbreaks in more than a dozen countries around the world with more than 3,000 clinical cases reported in the United States alone.

“We’re not taking a random approach to identify potential new antimicrobials,” Quave says. “Focusing on plants used in traditional medicines allows us to hone in quickly on bioactive molecules.”

Brazilian peppertree

Previously, the Quave lab had found that the berries of the Brazilian peppertree, a plant used by traditional healers in the Amazon for centuries to treat skin infections and some other ailments, contains a flavone-rich compound that disarms drug-resistant staph bacteria.

Screens by the Quave lab had also found that the leaves of the Brazilian peppertree contain PGG, a compound that has shown antibacterial, anticancer and antiviral activities in previous research.

The Brazilian peppertree, an invasive weed in Florida, is a member of the poison ivy family.“PGG has popped up repeatedly in our laboratory screens of plant compounds from members of this plant family,” Quave says. “It makes sense that these plants, which thrive in really wet environments, would contain molecules to fight a range of pathogens.”