NEW YORK (Reuters Health) – Substances isolated from bitter melon, a plant eaten and used medicinally in much of Asia, could provide the basis of new drugs for treating diabetes and obesity, an international team of researchers reports.

Also known as balsam pear, the vegetable has been shown to reduce blood sugar in animal and human studies, Dr. Mon-Jia Tan of the Chinese Academy of Sciences in Shanghai and colleagues note in the journal Chemistry & Biology.

Alternatives are needed to existing drugs for diabetes, they add, due to their side effects and limited action.

In the current study, Tan and colleagues isolated and described several compounds from bitter melon known as cucurbitane triterpenoids, and tested their effects on glucose (sugar) and fat metabolism in cells and in mice.

When tested in muscle and fat cells, the researchers found, the compounds stimulated the glucose receptor GLUT4 to move from the cell interior to the cell surface, thus promoting more effective glucose metabolism. Several of the tested compounds had effects comparable to those of insulin.

Tests in mice of two of the compounds found that they promoted both glucose tolerance and fat burning, and one was particularly effective in promoting glucose tolerance in animals consuming high fat diets.

The researchers note that there may be as many as 70 active compounds in bitter melon. “The present study provides an important basis for further analysis of structure-activity relationship to develop optimized leads from (bitter melon) for the treatment of insulin resistance and obesity,” they conclude.

SOURCE: Chemistry & Biology, March 2008.