An extract from the ginseng berry shows real promise in treating diabetes and obesity.

A research team from the University of Chicago tested the extract on mice bred to develop diabetes.

The ginseng fruit has enormous promise as a source of new drugs

Dr Chun-Su Yuan

Diabetes is linked to the body's inability to control levels of glucose in the blood - often because the hormone insulin is not functioning in a normal way.

Treatment with the extract was found to normalise blood sugar levels, and to boost the way insulin works.

In addition, cholesterol levels dipped, and the mice lost weight because they were stimulated to take more exercise and to eat less.

Key chemicals

Ginseng is a traditional Chinese medicine. Its root has been used for more than 2,000 years to treat a variety of ailments.

The study focused instead on the ginseng berry, which has very different concentrations of ginsenosides, the substances thought to be medically useful.

In particular, the scientists focused on ginsenoside Re, which is concentrated in ginseng berries but quite scarce in the root.

Researcher Dr Chun-Su Yuan said: "Ginseng berry has a distinctive chemical profile and has not previously been used for therapy.

"We were stunned by how different the berry is from the root and by how effective it is in correcting the multiple metabolic abnormalities associated with diabetes.

"Since this berry contains agents that are effective against both obesity and diabetes, the ginseng fruit has enormous promise as a source of new drugs."

The extract was injected once a day into mice with a gene defect that causes weight gain and Type 2 diabetes.

The scientists found:

• Blood-glucose levels fell from 222 mg/dl (quite high for a mouse) to 137 mg/dl (normal) within 12 days.
• Diabetic mice, which were also obese, lost more than 10% of their body weight in 12 days. Untreated mice gained 5% of their weight in 12 days.
• The treated mice ate 15% less and were 35% more active than untreated mice.
• Once the injections stopped, weight gain gradually resumed.
• The extract improved insulin secretion and insulin sensitivity, both of which were abnormal in mice with diabetes.
• Treated diabetic mice had 30% lower cholesterol levels than untreated diabetic mice

Tests using a ginsenoside Re alone found that it had all of the anti-diabetic but none of the obesity-fighting activities of the extract.

The next step will be to isolate the other substances in the extract, find out whether they also effect glucose regulation or weight gain.

The research is published in the journal Diabetes.