Thunder God Vine Chemical Causes Massive Weight Loss in Mice

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An artist's rendering of the thunder god vine and the leptin molecule. Eric Smith

A chemical found within the thunder god vine, a plant used in Chinese traditional medicine to treat various ailments, such as inflammation, caused mice to lose a dramatic amount of weight in a new study.

Mice given the substance, called celastrol, lost as much as 45 percent of their body weight, says Umut Ozcan, a researcher and physician at Harvard Medical School and Boston Children's Hospital. What's more, fat stores accounted for almost all of that weight loss, according to a study Ozcan co-authored that is published this week in the journal Cell.

No other substance has had such dramatic obesity-reducing and fat-burning properties in trials on mice to date, Ozcan says. Celastrol also doesn't appear to have toxic effects, at least in animals. He is working to start testing the chemical in humans in the near future, he says.

The chemical acts to increase the body's sensitivity to a hormone called leptin, which is secreted by fat cells. When leptin was discovered 20 years ago, there was great hope that it might be able to treat obesity, because in normal-weight individuals it reduces appetite. But in obese people, the hormone doesn't have the same effect; something about the excess of fat causes these individuals to be insensitive to leptin.

"Obese people's brains are deaf to leptin," Ozcan says.

In mice, celastrol intervenes in an inflammatory process within bodily cells that leads to leptin insensitivity. And Ozcan hopes it might be able to do the same in humans.

In the meantime, however, he definitely doesn't suggest that people take thunder god vine extract, since it contains many chemicals that aren't celastrol and their safety hasn't been adequately tested, he says. The leaves and stems of the plant are also highly toxic.

That said, some studies have suggested that various extracts, carefully made from peeled roots, may be relatively safe and useful in treating conditions besides obesity, specifically arthritis. A large 2002 study funded by the National Institute of Arthritis and Musculoskeletal and Skin Diseases found that an extract of the plant helped improve symptoms of arthritis more significantly than a conventional medicine known as sulfasalazine.