Quantitative studies of phytochemicals of selected green leafy vegetables and their antioxidant potential

Abstract

Methanolic extracts of Spinacia oleracea (Spinach), Coriandrum sativum (Coriander), Mentha sativa (Mint), Raphanus sativus (Radish), Amaranthus hypochondriacus (Amaranthus) were studied to identify the potential of these green leafy vegetables as antioxidants. In this regard free radical scavenging activity, reducing power and ferrous ion chelating activity of the extracts were determined. The selected vegetables were also analyzed for ascorbic acid, total carotenoid and total polyphenol contents, respective values of these phytochemicals in the vegetables under study ranged between 46.76 to 63.78, 0.006 to 0.074 and 289.69 to 1043.94 mg/100g. The highest free radical scavenging activity was recorded in Spinacia oleracea (13.87 ± 2.60 mg/ml), whereas it was found lowest in Amaranthus hypochondriacus (89.98 ± 1.42 mg/ml). Mentha sativa was found to have the maximum reducing power (1.68 ± 0.08 ASE/ml) and also the maximum hydroxyl radical (HO·) inhibition activity (78.87 ± 1.33%). Amaranthus hypochondriacus was found to have the minimum reducing power (0.45 ± 0.26 ASE/ml) and also the minimum HO· radical inhibition activity. Correlation coefficient indicated that the relationship of total antioxidant activity, free radical scavenging activity, and reducing power with total polyphenol and ascorbic acid was positively correlated.