ABSTRACT:
Diabetes mellitus is a metabolic disorder characterized by hyperglycemia and it is mainly linked with low blood insulin level or insensitivity of target organs to insulin. There are many clinical and experimental evidences indicating the involvement of oxidative stress in the pathogenesis of diabetes and more importantly in complications such as diabetic neuropathy, retinopathy and nephropathy. The state of increased oxidant stress is due to an increased production of free radicals as a result of persistent hyperglycemia and a sharp reduction of antioxidants defenses and the tissue antioxidant status which leads to the development of aforesaid diabetic complications. In Indian traditional system of medicine, numerous herbal remedies are prescribed for the treatment of diabetes. Treatment of diabetic patients with an antioxidant may prove to be advantageous in attenuating these complications. Most of the traditional herbal remedies employed for treatment of diabetes also exhibits potential antioxidant activity. The present work was based on comparative evaluation of antioxidant activity of some herbal antidiabetics namely, Trigonella foenum graecum, Catharanthus roseus L., Mangifera indica and Punica granatum using different systems of assay, e.g. DPPH radical- scavenging activity, superoxide radical-scavenging activity and hydroxyl radical-scavenging activity. The ethanolic extracts of the leaves of selected antidiabetic plants exhibited satisfactory scavenging effect in all the radical scavenging assays in a concentration dependent manner. Amongst the four aforesaid medicinal plants, Trigonella foenum graecum was found to be most effective followed by Catharanthus roseus, Mangifera indica and Punica granatum.