Evaluation of in vitro antioxidant activity of leaf extract of Alpinia malaccensis

Abstract

Many oxidative stress related diseases like cancer, diabetes, neurodegenerative disorders and cardiovascular diseases are occurring as a result of accumulation of free radicals in the body. Lots of researches are going on worldwide towards finding natural antioxidants of plant source. In the present study, the antioxidant activity of methanol extract of Alpinia malaccensis leaf was investigated using various in vitro methods. 1,1-diphenyl-2-picrylhydrazyl (DPPH), 2,2-azino-bis(3-ethylbenzthiazoline-6-sulphonic acid) (ABTS), nitric oxide (NO) and H2O2 radical scavenging assays as well as total phenolic content (TPC) of the extract was determined at different concentrations (10 to 500 μg/ml). The results indicated that the IC50 values of methanol extract of A. malaccensis were 22.5 μg/ml in DPPH, 72.38 μg/ml in NO, 26.23 μg/ml in ABTS and 80 μg/ml in H2O2 radical scavenging assay, respectively. The highest free radical scavenging activity of the leaf extract was observed at the concentration of 500 μg/ml. Furthermore, the TPC of the methanol extract of A. malaccensis was found to be 76.25 mg gallic acid equivalent (GAE)/g of extract. The results suggest that A. malaccensis has promising antioxidant activity and could serve as potential source of natural antioxidants. Key words: Alpinia malaccensis, leaf extract, antioxidant activity.