Comparison of antioxidant activity between decoction of dried Curcuma longa L., and Curcuma xanthorrhiza Roxb. rhizomes

Abstract

Free radical can cause the number of diseases. Almost plants produce antioxidant compounds, which have func- tion to neutralize or terminate the chain reaction of free radical. Curcuma longa and Curcuma xanthorrhiza are medicinal plants, that the main constituent in the rhizomes is curcuminoid, which has antioxidant activity. The objective of the research is to compare the antioxidant activity between the dried decoction rhizomes. The rhi- zomes were screened of the phytochemical constituents. The decoctions were made by boiled of 3.98 g dried rhi- zomes at 90⁰C during 30 minutes, volume to be kept at constant, and then were filtered and the supernatants were evaporated on the water bath. Curcumin were isolated with 50 ml methanol, and antioxidant activity were determined with 2,2-diphenyl-1-picrylhydrazyl (DPPH) assay. Phytochemicals screening of both showed of positive results for the presence of alkaloid, saponin, quinon, and steroid/triterfenoid. Antioxidant activity of decoction of dried Curcuma longa is 18.4 μg/ml and Curcuma xanthorrhiza is 10.5 μg/ml. In conclusion, the antioxidant activity of dried decoction Curcuma xanthorrhiza is higher than Curcuma longa, and both of decoctions have very strong antioxidant activity.