Most Americans have used herbal drugs during the past year, even though in nearly all cases there is no clear scientific evidence that they work. Now, an international team of scientists has found a way to collect that evidence, and even determine which components of very complex compounds are doing the work, and which aren't.
The effort is lead by Yuan Luo, an associate professor in the University of Maryland's department of pharmaceutical science, who grew up in China where many herbal remedies that are used today have been used for thousands of years.
"This provides the first step to find, from all of the hundreds of compounds in herbs, which ones have potential for medicinal purposes. And you can do this very quickly and efficiently," said Laura Dosanjh, a graduate student and coauthor of a paper describing the research in the journal PLoS ONE.
The first results suggest that two very popular herbs, cinnamon and ginseng, can potentially extend lifespan. But that's based on research with the star of this show, a transparent earthworm, C. elegans, which has become a real workhorse in labs around the world because of genetic similarities with higher animals, including humans.
"Nobody is saying this will increase the lifespan in humans, because that research has never been done," Luo said in a telephone interview. But the results in C. elegans are tantalizing. Cinnamon alone was found to increase the lifespan of the worm by up to 14.5 percent.
Luo's technology could help answer questions that have bedeviled health professionals for years. Herbs are medicines, although they have never gone through the clinical trials required for approval by the Food and Drug Administration.
Those trials are very expensive, and pharmaceutical companies that normally pay for the trials have no incentive to do so for herbs that are already on the market because they cannot be patented. Thus, no profit motive leads to very little evidence that any of them work.
What is left is anecdotal evidence from people who have used them and claim to have benefited. That is what has kept the drugs so popular in China for many generations, said Luo, who came to the United States for graduate school and never left.
"When people are weak or they are old they drink green tea and they feel better," she said. "That's why they think this is good. It's not experimental evidence."
When she set out to fill that evidentiary gap a few years ago she turned to C. elegans, a tiny worm, about the size of a human eyelash, that has played a critical role in genetics research. Sydney Brenner, who won the Nobel prize in 2002 for his work with the worm, introduced C. elegans to the laboratory in 1974, and the rest, as they say, is history.
This remarkable worm has 20,000 genes, many of which perform the same functions in both the worm and humans, so its arrival gave researchers a chance to find out which genes were responsible for which activities in the worm, and as it turned out in many cases, in humans as well.
The worm has a lifespan of only two to three weeks, so it is possible to carry out experiments in a brief period of time. It is fairly easy to disable various genes, thus making it easier to determine their functions, and the worms can be frozen and stored, then awakened to do their job.