Researchers at Helmholtz Zentrum München have found that Celastrol, a plant-derived substance used in traditional Chinese medicine, shows potential for combating obesity by activating centers in the brain responsible for producing feelings of fullness. Although the team's experiments only involved mice, the mechanism the substance acts on operates similarly in humans, and clinical trials are already underway.

Celastrol, or triperine, is a chemical compound found in the root extracts of a plant called Tripterygium wilfordii, which is sometimes called thunder god vine. This plant has long been used as a traditional Chinese treatment for a variety of conditions, such as rheumatoid arthritis and psoriasis, but its use is not recommended due to various significant side effects. But now researchers in the Neurobiology of Diabetes department at the Helmholtz Zentrum München have shown that Celastrol can trigger significant weight loss, and therefore a reduction in the risk of developing diabetes, in obese mice.

In mice – and humans – the hormone leptin helps regulate energy homeostasis by inhibiting hunger. However, obesity can trigger leptin resistance, which prevents the hormone from activating leptin receptors in the brain and feelings of fullness even after eating fail to arise. By using leptin receptor-deficient mice, it was this mechanism that the researchers were able to prove that Celastrol affects.

"Celastrol reactivates the body's own mechanisms for controlling weight that would otherwise be switched off in obese individuals," says Katrin Pfuhlmann, PhD student and first author of the study. "Normally those affected lose that feeling of fullness because the respective hormone – leptin – no longer has any effect. Celastrol, the compound we examined, restores leptin sensitivity and thus the sense of satiety."

When overweight mice were administered Celastrol, the researchers saw a significant drop in the animals' food intake, which corresponded with an average loss in body weight of around 10 percent in just one week. However, no differences were observed in the leptin receptor-deficient mice. Whether similar results would be seen in humans remains unknown, but we may soon have answers.

"Relevant clinical trials are currently taking place in the United States, and we eagerly await the initial results," says Dr. Paul Pfluger, last author and head of the study.

Even if the compound does prove similarly effective in humans, the researchers are keen to point out that it would not be a magic bullet for weight loss, negating the need for changes in eating habits and lifestyle, but rather a potential aid for those attempting to lose weight.

The team's study appears in the journal Diabetes.