by Kate Dohner
One in three Americans uses herbal therapies. Yet less than one in 3,000 scientific studies focus on this increasingly popular therapy.
Researchers at the Tang Center for Herbal Medicine Research at the University of Chicago are changing that. Established in 2000 through generous donations from the foundations of Cyrus Tang, the Tang Center seeks to uncover the benefits and potential dangers of herbal therapies.
“The majority of prescription medications are derived from natural products,” explained Chun-Su Yuan, MD, PhD, Cyrus Tang Professor and director of the Tang Center. “At the Tang Center, we apply a scientific approach to identify new herbal therapies and gain a better understanding of how they might help patients.”
Yuan and his colleagues were among the first to point out that—because most herbal medicines are taken by mouth (as capsules or teas)—they must be digested and absorbed by the microbiome, the trillions of bacteria that live in each person’s gut.
One of the most popular herbal medicines worldwide, ginseng has been used for centuries to treat a variety of ailments. In recent years, it was discovered that after ginseng is consumed, its original compounds are transformed by certain gut bacteria into new substances called metabolites—one of which, “compound K,” has significant cancer prevention potential.
Yuan and his team are studying ginseng’s ability to fight colorectal cancer, one of the most common cancers worldwide. This work, previously supported by a $6 million grant from the National Institutes of Health, led to an important discovery: When ginseng was fed to mice with colorectal cancer, it not only significantly reduced inflammation in the colon but also restored the bacterial community to a healthy state.
In a related study, Yuan’s team examined how American ginseng (one of the main species of ginseng) affects the microbiomes of people who eat different diets. They studied six volunteers in the Chicago area—half of whom regularly ate an Asian diet of largely vegetables and rice, and half who ate a high-fat, Western diet. Each of the participants took ginseng capsules by mouth for seven days.
The researchers found that those on the Western diet had much higher levels of cancer-fighting compounds compared to those on the Asian diet. This preliminary study suggests ginseng may be even more beneficial for those who eat a Western diet.
“This was not what we expected,” offered Yuan. “However, the high-fat diet appears to affect the composition of gut bacteria, and in turn, allows for better absorption of ginseng’s anti-cancer compounds.”
Looking ahead, Yuan seeks to study ginseng’s influence on the microbiome in greater depth, eventually moving into clinical trials. But more animal studies are needed first.
“The general public is very enthusiastic about dietary supplements and herbal medicine,” said Yuan. “With continued research, we hope to provide unbiased scientific findings to help inform the medical community, patients, and health-conscious consumers.”
Kate Dohner is a senior writer for the University of Chicago Medicine & Biological Sciences Development office.