Evaluation of the antioxidant activity of tumeric (curcuma longa) / Nordayanti Mohd Rosdi

The antioxidant capacities of the aqueous extract of the rhizome of Curcuma longa, a spice known as turmeric or 'kunyit' by Malaysian community, were investigated. The antioxidant capacity was evaluated by different methods such as total phenolic assay (TPA), free radical (DPPH) scavenging activity, and ferric reducing power ( FRAP) assay. The total phenolic content was 0.099 ± 0.016 mg/mg of extract expressed as gallic acid equivalents. In the FRAP assay, the results showed only 0.27 ± 0.05 µg/ml, while the controls, trolox, ascorbic acids and curcumin, produced 7.38 ± 0.91 µg/ml, 7.61 ± 0.42 µg/rnl, 5.87 ± 1.74 µg/ml respectively. The median inhibitory concentration (IC50) for free radical scavenging of DPPH was at a concentration of 10 mg/ml, C. longa aqueous extract exerted about 10 % DPPH scavenging activity. As a conclusion the aqueous extract of Curcuma longa possesses antioxidant activity and support the previous report that phenolic compounds are accountable for antioxidative activity.