Abstract

In the present study, the antioxidant potential of the crude methanol and its fractionated extracts (hexane, ethyl acetate and water) of the rhizomes of Alpinia mutica was investigated, employing four different assays. The antioxidant assays used were 2, 2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging, b-carotene bleaching,superoxide dismutase (SOD) and the reducing power assays while the total phenolic content was assessed using the Folin-Ciocalteu method. The ethyl acetate fraction showed the highest antioxidant property in comparison to the other extracts against all assays conducted. The ethyl acetate fraction displayed better antioxidant activity in comparison to the standard compound, butylated hydroxyanisole (BHA) and ascorbic acid in the b-carotene linoleate model system and the SOD assay. The ethyl acetate fraction was also found to have the highest phenolic content among the extract and fractions. The phenolic compounds present in the ethyl acetate fraction may have contributed to the good antioxidant properties of the ethyl acetate fraction. In conclusion, the rhizome extract of A. mutica especially the ethyl acetate fraction possesses good antioxidant activity and can be potentially used as natural antioxidants.

Key words: Alpinia mutica, antioxidant, radical scavenger, flavonoid, total phenolic content.