Berberine is found in the roots and bark of a number of plants used for medicinal purposes including wound healing and treatment of diarrhoea. It has also been documented in Chinese literature as having a glucose lowering effect when administered to people with diabetes; yet, until now, its mode of action was unknown.
Garvan scientist Dr Jiming Ye says: "Our studies in animal models of diabetes show that berberine acts in part by activating an enzyme in the muscle and liver that is involved in improving sensitivity of the tissue to insulin - this in turn helps lower blood sugar levels. In addition, it seems berberine can help reduce body weight".
Current medicines for treating type 2 diabetes include metformin and the TZD group of drugs. However, a large number of patients cannot tolerate metformin and the TZDs can cause undesirable weight gain. Therefore, it is critical to develop new therapies to treat type 2 diabetes, which is a growing health problem.
"Berberine has been used for decades, if not centuries, with few reported side effects. Given the limitations of existing medicines we are excited to have evidence that berberine may be a helpful new treatment for type 2 diabetes; however, despite its widespread use in traditional medicine practices, it will still have to be evaluated properly following the defined clinical trials process", said Professor James, head of the Garvan's Diabetes & Obesity Research Program and co-author of the Diabetes paper.
The next step is to investigate how berberine activates the enzyme that mediates these 'insulin-sensitising' effects.
This study will be published in the August issue of 'Diabetes'. The title is: Berberine, a natural plant product, activates AMP-activated protein kinase with beneficial metabolic effects in diabetic and insulin resistant states. Yun S. Lee, Woo S. Kim,Kang H. Kim, Myung J. Yoon, Hye J. Cho, Yun Shen, Ji-Ming Ye, Chul H. Lee, Won K. Oh, Chul T. Kim, Cordula Hohnen-Behrens, Alison Gosby, Edward W. Kraegen, David E. James, and Jae B. Kim
Berberine (or plant material containing berberine) has also been documented as having anti-microbial, antitumour and anti-inflammatory properties as an oral medicine.
Additional information from the University of California San Diego website:
The combination herbal supplement of echinacea and goldenseal has emerged as one of the top five herbal supplements sold in the world-wide market with annual sales in the US close to $50 million. Despite its popularity, much of the peer reviewed literature available on goldenseal deals specifically with the plant alkaloid component berberine, and not the herbal supplement itself. The berberine component of goldenseal is not considered toxic at doses used in clinical situations.