Role of Medicinal Plants in Diabetes Managements

Diabetes mellitus is one of the fastest growing metabolic disorders in the world today, and India carries one of the largest shares of this burden. Although insulin and oral hypoglycaemic drugs are widely used to manage blood glucose, many patients still experience poor glycaemic control, side effects and a heavy financial burden over the years. Because of this, more attention is now being given to plants that have been used for centuries in Ayurveda, Siddha and folk medicine to treat “madhumeha” (sweet urine disease), the traditional name for diabetes. Trigonella foenum-graecum, Azadirachta indica, Syzygium cumini, Allium sativum, Ocimum sanctum, Cinnamomum verum, Aloe vera, Pterocarpus marsupium, Tinospora cordifolia and Catharanthus roseus. For each plant, the botanical description, the active phytoconstituents and the reported mechanism of antidiabetic action have been discussed, along with available preclinical and clinical evidence. The general mechanisms by which these plants help to lower blood glucose are also explained, namely insulin secretagogue action, insulin-mimetic activity, inhibition of carbohydrate digesting enzymes, increased GLUT-4 mediated glucose uptake, protection of pancreatic beta cells and antioxidant action. Marketed polyherbal formulations, their safety profile and the concerns related to herb-drug interactions and lack of standardisation have also been summarised.