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Herbal Evaluation
MIT scientists analyze ginseng to understand its effects
By Katharine Dunn

Depending on where it’s from and how it’s made and who sells it, the herbal supplement ginseng may claim to fight cancer or impotence, “nervous exhaustion” or stomachaches, to stimu­late the immune system or enhance cognitive function, or even to work as an aphrodisiac. Ginseng’s genus, after all, is Panax, as in panacea.

Though consumers may think of the root as a cure-all, two MIT scientists and a team of international researchers have focused on two of its effects: it promotes the growth of blood vessels, which helps in wound healing, for example, or it does the opposite and stunts their growth, which is useful for cancer treatment, because tumors cannot survive without an active supply of blood. The researchers hope their work will convince the U.S. Food and Drug Administration to regulate dietary supplements. Herbal remedies are currently governed by a 1994 law that does not mandate the rigorous testing that pharmaceuticals are subject to; manufacturers may also tinker with the proportions of dietary supplements’ ingredients without informing the government agency.

“You can crush [the ginseng root] and say it has been tested to do something and then sell it. We’re saying there should be rules in place,” says Shiladitya Sengupta, a postdoctoral associate who was part of the team that studied the effects of the popular remedy. Ram Sasisekharan, a professor in the biological-engineering division who was also part of the team, explains that “just because they’re natural doesn’t mean they’re safe.” He notes that it could be dangerous for a cancer patient to take ginseng that promotes blood vessel growth.

In their recent paper in Circulation, the journal of the American Heart Association, the researchers show that there are two distinct ingredients in ginseng, one that encourages blood vessel growth and one that does the opposite. The supplement’s effect varies with the ratio of these ingredients, which different processing methods modify in different ways. Using mass spectrometry, the researchers analyzed the chemical components of three species of ginseng from three countries, then mimicked the steps of blood vessel formation with cells in culture to determine the effects of each ginseng-derived compound. They confirmed their findings by treating mice with fixed amounts of the compounds.

Sengupta started the research in 1999 as a PhD student at the University of Cambridge, where he analyzed ginseng roots given to him by scientists in Hong Kong. Sasisekharan, an expert in complex sugars, became involved because where sugars attach to the compounds in ginseng influences how it affects users. Sengupta and Sasisekharan are now trying to further clarify the role sugars play.

The researchers hope to modify the molecules in the future so that they’re more potent and can be made into effective medicines. Sengupta says powerful wound-healing drugs could make a difference to tens of thousands of diabetics who lose feet or legs every year from nerve and artery damage. They also hope to convince the FDA to standardize and regulate ginseng and other herbal supplements, forcing manufacturers to make sure their supplements have the advertised effects. Though the ginseng findings have been covered by the press around the world, Sengupta knows it will take more than media buzz to get the government involved. He and his colleagues plan to devise a rigorous method for standardizing herbal supplements and to present it to the FDA.