Abstract
The present study evaluates anti-hyperglycemic activity of fractionated Momordica charantia (bitter gourd) seed extracts. Fasting blood glucose levels were evaluated before and after administration of different fractions of the seed extract. Among the three fractions tested, fraction Mc-3 (15 mg/kg b.wt.) showed the maximum anti-hyperglycemic activity and reduced blood glucose levels in experimental diabetic rats significantly. The activities of the key regulatory enzymes of glucose metabolism (hexokinase, pyruvate kinase, lactate dehydrogenase, and glucose-6-phosphate dehydrogenase) were determined in Mc-3-treated diabetic animals. Once-daily administration of the fraction Mc-3 for prolonged period of 18 days to the experimental diabetic animals did not result in any nephrotoxicity or hepatotoxicity as evident from insignificant changes in biochemical parameters indicative of liver and kidney functions. Further fractionation of the fraction Mc-3 by size exclusion chromatography resulted in a fraction, designated Mc-3.2, possessing anti-hyperglycemic activity. The fraction Mc-3.2 showed the presence of a predominant protein band of ~11 kDa on SDS-PAGE. Loss in anti-hyperglycemic activity of the Mc-3.2 upon protease treatment indicates the proteinaceous nature of the anti-hyperglycemic principles. Overall, the results suggest that Momordica charantia seeds contain an effective anti-hyperglycemic protein(s) which may find application in treatment of diabetes without evident toxic effects.