The aim of the present study was to investigate the long-term effects on blood glucose concentrations and possible adverse effects of an extract of Gynostemma pentaphyllum (GP). This is a plant growing in the mountain regions of Northern Vietnam and previously being used in traditional medicine. The GP extract, or placebo, was randomized to newly diagnosed patients with type 2 diabetes and administered as a "tea", 3 g two times daily during 12 weeks. All patients received instructions regarding diet and physical exercise. Oral glucose tolerance tests were performed at baseline and then every 4 weeks, and blood tests were taken with the purpose to monitor lipids, kidney and liver function, body weight and blood pressure.

In Vietnam, herbal extracts have been used as a long-standing tradition to treat diabetic patients, but effects of these extracts have not been studied adequately. Based on previous results in experimental animals, we have selected the plant Gynostemma pentaphyllum (GP), which grows in the mountain region of Northern Vietnam. GP extract had a hypoglycemic effect on mice and rats, and was shown to contain a substance, phanoside, which stimulates insulin secretion. In addition, GP has been shown to reduce both hyperglycemia and hyperlipidemia in diabetic Zucker fatty rats.

The present study aimed at investigate effects of GP extract, administered as a "tea", and compared with placebo in a randomized, double-blind trial in drug-naive patients with newly diagnosed type 2 diabetes. All patients also received instructions about diet and physical exercise. In addition to monitoring effects on plasma glucose regulation, we also studied possible effects on plasma lipids, kidney and liver function as well as body weight and blood pressure.

Inclusion Criteria:

• Newly diagnosed, drug-naive patients with type 2 diabetes
• Fasting plasma glucose (FPG) 7.0-14.0 mmol/l
• HbA1c > 6%

Exclusion Criteria:

• Type 1 diabetes
• Liver failure
• Kidney Failure