The efficacy of Silybum marianum (L.) Gaertn. (Silymarin) in the treatment of type II diabetes

Diabetes is a growing health problem. Giving antioxidants is recognised as one way of helping people with diabetes to control their blood sugar levels.

The herbal medicine extracted from seeds of the Milk Thistle, Silybum marianum (silymarin) is known to have antioxidant properties and research published this week in Phytotherapy Research shows that this extract can help people significantly lower the amount of sugar bound to haemoglobin in blood, as well as reducing fasting blood sugar levels.

Silymarin contains a number of active constituents called flavolignans which are also used to help protect the liver from poisoning.

"We don't know the exact mechanism of action for this effect, but this work shows that silymarin could play an important role in treating type II diabetes," says lead author Fallah Huseini, who works at the Institute of Medicinal Plants, which is based in Tehran, Iran.

The data came from a randomized double-blind clinical trial involving 51 people who had had type II diabetes for at least 2 years. One group of 25 patients received 200 mg of silymarin three times a day for 4 months, while the remaining 26 received a placebo treatment. All of the patients continued to use conventional oral hypoglycaemic treatment during the trial. Patients were examined at monthly intervals.

Compared with the beginning of the trial, the treatment group had a significant reduction in fasting blood glucose levels (p<0.001), and a reduction in glycosylated haemoglobin (p<0.001). Both of these measures rose significantly in the placebo group (p<0.0001). There were also non-significant decreases in blood lipids in the treatment group.

"The results are very encouraging, and we now need to do further large multi-centre studies," says Huseini.