Studies on Indian green leafy vegetables for their antioxidant activity.

To identify the potential of green leafy vegetables (GLV) as antioxidants, methanolic extracts of Amaranthus sp., Centella asiatica, Murraya koenigii and Trigonella foenum graecum were studied for their antioxidant activity in different systems at multiple concentrations. Total antioxidant activity assessed by phosphomolybdenum method, free radical scavenging activity by 1,1-diphenly-2-picryl hydrazyl (DPPH), reducing power and ferrous ion chelating activity were determined. The GLV were analyzed for ascorbic acid, total and beta-carotene and total polyphenol contents. The ascorbic acid, total carotene, beta-carotene and total phenolic content (tannic acid equivalents) of the GLV ranged between 15.18-101.36, 34.78-64.51, 4.23-8.84 and 150.0-387.50 mg/100 g GLV, respectively. The extracts were found to have significantly different levels of antioxidant activities in the systems tested. The total antioxidant activity was highest in Murraya koenigii (2,691.78 micromol of ascorbic acid/g sample) and least in Centella asiatica (623.78 micromol of ascorbic acid/g sample). The extract concentration causing 50% inhibition of DPPH (IC50) was determined (M. koenigii<C.asiatica<Amaranthus sp.<T. graecum). The maximum DPPH scavenging activity and reducing power was exhibited by Murraya koenigii. Multiple regression analysis showed that the relationship of total antioxidant activity, free radical scavenging activity, and reducing power with polyphenol and total and beta-carotene was highly significant.