Dietary antioxidant activities in different germplasms of Mucuna

Mucuna pruriens, an underutilized native legume of South India has been reported to have high levels of L-Dopa, and used in the treatment of Parkinson's disease. Cellular damage arising from reactive oxygen and nitrogen species is said to cause neurodegenerative disorders. Antioxidants could assuage this oxidative damage of tissue directly and/or indirectly by enhancing natural defenses and also scavenging the free radicals. In this context, the antioxidative potential of different germplasm of Mucuna species was analyzed. Assays were performed to evaluate the enzymatic and nonenzymatic antioxidants in the extracts. Methanolic extracts of Mucuna (black germplasm) yielded high levels dietary antioxidants viz., flavonoids, alkaloids, saponins, steroids and phlobotannins qualitatively. Tannins, total phenols, flavanoids, and steroids accounted for 13.60±1.8 tannic acid equivalents, 58.47±3.19 gallic acid equivalents, 23.7±3.12 quercetin equivalents, and 20.3±1.0 mg per 100 mg β-sitosterol equivalents, respectively. Percentage of scavenging activity against hydroxyl, superoxide anion, nitric oxide, and hydrogen peroxide radicals were 39.12%; 57.1%; 41.26%, and 25.68%, respectively. Reducing capacity (17.74%) was seen to concurrently increase with extract concentration. Catalase, glutathione reductase, and polyphenol oxidase activities were found to be 30.15; 26.6 and 42.5 μmol/mg of protein, respectively. The methanolic extract yielded the most potent levels of dietary antioxidants and exhibited high free-radical-scavenging activity.