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Antidiabetic actions of aqueous bark extract of Swertia chirayita on insulin secretion, cellular glucose uptake and protein glycationThomson, HeatherAnne; Ojo, Opeolu; Flatt, Peter; AbdelWahab, Yasser (ScopeMed International Medical Journal Management and Indexing System, 2014-12-07)Objective: There is renewed scientific interest in the potential of plant-derived agents for the treatment of diabetes mellitus. This study investigated the antidiabetic actions of Swertia chirayita, a plant used traditionally in the management of diabetes. Methods: Insulin secretion from BRIN-DB11 cells was assessed in the absence or presence of plant extract and modulators of beta cell function. Glucose uptake was assessed using 3T3-L1 cells while effects of the plant extract on protein glycation was assessed using model peptide. Insulin was measured by radioimmunoassay and intracellular calcium by FLEXstationTM. Results: Swertia chirayita stimulated concentration-dependent insulin secretion from BRIN-BD11 cells (P<0.001). Its insulinotropic effects were abolished in the absence of extracellular Ca2+ or by diazoxide (P<0.001, n=8) and were significantly decreased by verapamil and in beta cell depolarization by with KCl. Swertia chirayita extracts evoked a 28 – 59% increase in basal and insulin-stimulated glucose uptake by 3T3-L1 cells. Protein glycation was significantly (P<0.05 – P<0.001) inhibited by S. chirayita in a dose-dependent manner. Conclusion: This study reveals that the antidiabetic actions of S. chirayita aqueous bark extracts involves the stimulation of insulin secretion and enhancement of insulin action. Inhibition of protein glycation may also help counter diabetic complications. These actions of S. chirayita may provide new opportunities for the treatment of diabetes.