Antioxidant Potential of the Polyphenolics in Grewia asiatica, Eugenia jambolana and Carissa carandas

Abstract

The fruits G. asiatica, E. jambolana and C. carandas were extracted with methanol and the extracts were partitioned into four polyphenolic fractions: Flavanols, flavonols, phenolic acids and anthocyanins using solid phase extraction. Each fraction was then analyzed for total phenolics, flavonoids, antioxidant activity by DPPH, beta-carotene-linoleic acid assay and total reducing power. Total phenolics ranged 6.64-107, 56.20-398, 33.38-315 and 20-201 mg/100 g in phenolic acid, flavanol, flavonol and anthocyanin fractions respectively of these fruits which explained the order of their antioxidant activity and reducing power as flavanols > flavonols > anthocyanins > phenolic acid. Total phenolics were highest in E. jambolana fractions (107-398 mg/100 g) but the maximum antioxidant activity (62-85% in 2,2-diphenyl-1-picrylhydrazyl (DPPH) and 58-89% in ?-carotene-linoleic acid assay) was shown by the fractions in G.asiatica (total phenolics, 67-151 mg/100 g). At all concentrations, the DPPH scavenging activity of flavanol fraction in G. asiatica (85% at 20 ppm) was comparable to BHA (89%).