Ginseng extract halts diabetes in mice. (Biomedicine).

While the root of the ginseng plant has been used for more than 2,000 years in Asian medicine, the ginseng berry has seldom served as a remedy. A study now finds that extracts from the berry of Panax ginseng can counter obesity and insulin resistance in mice.

In insulin-resistant mice and people, cells fail to use the hormone efficiently as a signal to process sugars and starches. The condition is the hallmark of type II, or adult-onset, diabetes, which is the most common form of the disease.

In the June Diabetes, researchers report injecting obese, insulin-resistant mice with berry extract daily for 12 days. By the trial's end, the mice were processing sugars and starches as efficiently as lean mice were and had lost weight, dropping from 52 grams on average to less than 46 grams. Insulin concentrations in the blood of obese mice had fallen to near-normal levels, suggesting these animals had overcome insulin resistance.

A control group of obese mice given saline shots continued to be insulin resistant. Lean, healthy mice injected with berry extract were unaffected, says study coauthor Chun-Su Yuan, a clinical pharmacologist at the University of Chicago's Tang Center for Herbal Medicine.

To determine what substance is responsible for the extract's effects, the researchers injected one berry ingredient, ginsenoside Re, into obese, insulin-resistant mice. The animals' sugar metabolism improved, but they didn't lose weight. That suggests some other, still-undiscovered ingredient in the berry accounts for the weight loss, Yuan says.

The mechanisms by which Chinese herbs work are poorly understood, says nutritionist Cyril W.C. Kendall of the University of Toronto. Although he considers these findings on ginseng berries preliminary, the research "is very interesting" and the berries merit further study, he says.--N.S.