Antioxidant activity and isolation studies of extracts of seeds of Syzygium cumini L

The seeds of Syzygium cumini L. (Family: Myrtaceae), a well-known medicinal and fruit plant, are used to treat a number of diseases involving free radicals, therefore the present study aims to investigate its extracts for antioxidant activity and isolation of active constituent(s). In 1,1-diphenyl-2-picryl hydrazyl (DPPH) assay, methanol extract and its hexane fraction showed 68.54% and 58.42% free radical scavenging activity, respectively (Fig. 1). The extract and fraction also showed higher antioxidant activity in β-carotene-linoleate assay. From the hexane fraction, caffeic acid (I) was isolated and identified. Methanol extract and hexane fraction were found to contain 74.27 and 40.68 mg/g caffeic acid, respectively. The findings of the present study indicate that the methanol extract of seed of Syzygium cumini and its hexane fraction have good antioxidant activity, and contain caffeic acid, a known antioxidant.

Fig. 1. The antioxidant activity of extracts and fractions of seed of Syzygium cumini, and standards using DDPH assay