An extract from the ginseng berry could prove to be an effective treatment for diabetes and obesity, according to researchers from the University of Chicago.
Writing in the June issue of the journal Diabetes, the team from the University's Tang Center for Herbal Medicine Research claimed that the ginseng extract could normalise blood glucose levels, improve insulin sensitivity and lower weight by helping to reduce appetite.
The team, led by Chun-Su Yuan, assistant professor of anaesthesia and critical care at the University of Chicago, focused on ginseng berries rather than the root, the part of the plant which has been used in traditional Chinese medicine for centuries.
"Ginseng berry has a distinctive chemical profile and has not previously been used for therapy," said Yuan. "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."
Yuan's team studied the effects of the extract made from the pulp of the berry, focusing on one particular substance known as ginsenoside Re, which is concentrated in ginseng berries but quite scarce in the root.
They tested the extract by injecting it once a day into mice engineered to be obese and suffering from type 2 diabetes. They discovered that a daily injection of 150 mg/kg of the ginseng berry extract restored normal blood-sugar levels in the diabetic mice, with blood-glucose levels falling from 222 mg/dl (quite high for a mouse) to 137 mg/dl (normal) within 12 days. Treated mice also had better scores on a glucose tolerance test, which measured how quickly the mice could remove excess glucose from the blood.
The extract also caused the obese diabetic mice to lose more than 10 per cent of their body weight in 12 days. Untreated mice gained five per cent of their weight in 12 days. The treated mice ate 15 per cent less and were 35 per cent more active than untreated mice. Once the injections stopped, weight gain gradually resumed, Yuan's team found.
The extract also improved insulin secretion and insulin sensitivity, both of which were abnormal in mice with diabetes, while the treated diabetic mice had 30 per cent lower cholesterol levels than untreated diabetic mice. The extract had no detectable effect on normal mice, the researchers said.
When Yuan's team focused on ginsenoside Re alone, they found that it was just as effective as the extract at fighting diabetes, but that it was completely ineffective at combating obesity. "This novel compound could serve as the basis for a whole new class of anti-diabetic medications," said Yuan, who is also working to isolate other substances from the extract that contributed to the weight loss.
"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," said Yuan, who has worked with the University to apply for a patent on the development of ginsenoside Re as a diabetes medication.
"The next step is to isolate the other substances in the extract, find out whether they also effect glucose regulation or weight gain, learn how they work and determine the safe and effective dose."