A novel Gymnema sylvestre extract stimulates insulin secretion from human islets in vivo and in vitro.

Many plant-based products have been suggested as potential antidiabetic agents, but few have been shown to be effective in treating the symptoms of Type 2 diabetes mellitus (T2DM) in human studies, and little is known of their mechanisms of action. Extracts of Gymnema sylvestre (GS) have been used for the treatment of T2DM in India for centuries. The effects of a novel high molecular weight GS extract, Om Santal Adivasi, (OSA(R)) on plasma insulin, C-peptide and glucose in a small cohort of patients with T2DM are reported here. Oral administration of OSA(R) (1 g/day, 60 days) induced significant increases in circulating insulin and C-peptide, which were associated with significant reductions in fasting and post-prandial blood glucose. In vitro measurements using isolated human islets of Langerhans demonstrated direct stimulatory effects of OSA(R) on insulin secretion from human ß-cells, consistent with an in vivo mode of action through enhancing insulin secretion. These in vivo and in vitro observations suggest that OSA(R) may provide a potential alternative therapy for the hyperglycemia associated with T2DM.

Effect of dietary supplementation of vitamin E in partial inhibition of Russell's viper venom phospholipase A2 induced hepatocellular and microsomal membrane damage in rats.

The current investigation furnishes a good correlation between the alpha-tocopherol content of the liver and microsomes and corresponding inhibition of Russell's viper venom phospholipase A2 inflicted damage to them. Dietary supplementation of d1-alpha-tocopherol at a concentration of 100 mg and 200 mg per kg of diet displayed less damage caused by venom phospholipase A2 in sharp contrast to the vitamin E deficient rats. alpha-tocopherol due presumably to the formation of complexes with the phospholipid hydrolysis products of the membranes, plays a significant role in membrane stabilization.