Antidiabetic effect of tetrahydrocurcumin and ptrostilbene on endothelial dysfunction

Abstract

Endothelial dysfunction plays a key role in the pathogenesis of diabetic vascular disease. Endothelial dysfunction is an imbalance in the production of vasodilator factors and when this balance is disrupted, it predisposes the vasculature towards pro-thrombotic and pro-atherogenic effects. This results in vasoconstriction, leukocyte adherence, platelet activation, mitogenesis, pro-oxidation, impaired coagulation and nitric oxide production, vascular inflammation, atherosclerosis and thrombosis. Endothelial dysfunction is focussed as it is a potential contributor to the pathogenesis of vascular disease in diabetes mellitus. The active components of Curcuma longa such as curcumin and tetrahydrocurcumin (THC), a major colourless metabolite of curcumin also possesses antidiabetic, antiinflammatory and antioxidant activity. Pterostilbene (PTS) was found to be one of the active constituents in the extracts of the heartwood of P. marsupium. The water stored in tumblers made out of the heartwood of P. marsupium is used as a traditional therapy for patients with diabetes mellitus. In the present study, we assessed the effects of THC and PTS also its preventive qualities. Using an animal model, assessment for endothelial-dependent vasodilatation and the behavior of leukocytes were accomplished by using streptozotocin (STZ) - nicotinamide induced diabetic rats and its mesenteric microcirculation parameters. The results indicated that both antioxidants, THC and PTS, could significantly inhibit those abnormalities typically seen in endothelial dysfunctions (P < 0.05) in relation to their hypoglycemic and hypolipidemic properties. The THC administration showed more effective than PTS.