Antioxidant Capacity and Total Phenolic Content of Moringa oleifera Grown in Chiang Mai, Thailand

Leaves, pods and seeds of Moringa oleifera (variety: Num Phare, Ang Thong, and PKM1) grown in Chiang Mai, Thailand, were extracted with water or 95% ethanol and their antioxidant capacities were estimated using a Ferric Reducing Antioxidant Power (FRAP), an improved ABTS radical cation decolorization assay, and a DPPH free radical scavenging activity assay; together with determination of their total phenolic contents by the Folinciocalteau micro method. The results of aqueous extracts (0.80 – 12.25 mg standard equivalent per gram of dry weight) were greater than those of ethanolic extracts (0.40 – 8.85 mg standard equivalent per gram of dry weight). Leaf extracts (1.80 – 12.25 mg standard equivalent per gram of dry weight) showed the highest antioxidant capacity and total phenolic content, followed by those of pods (1.80 – 6.54 mg standard equivalent per gram of dry weight) and seeds (0.40 – 1.79 mg standard equivalent per gram of dry weight), respectively. Leaf extracts of Ang Thong and PKM1 varieties (2.08 – 12.25 mg standard equivalent per gram of dry weight) were composed of higher antioxidant capacities and total phenolic contents than those of Num Phare variety (1.80 – 10.10 mg standard equivalent per gram of dry weight). Pod extracts of Ang Thong and PKM1 varieties (3.53 – 6.54 mg standard equivalent per gram of dry weight) consisted of higher reducing power (FRAP values) and total phenolic contents than those of Num Phare variety (2.59 – 3.61 mg standard equivalent per gram of dry weight). The FRAP value and total phenolic content of Ang Thong seed extracts (0.95 – 1.65 mg standard equivalent per gram of dry weight) were larger than those of PKM1 and Num Phare seed extracts (0.73 – 1.30 mg standard equivalent per gram of dry weight) while the ability to quench both ABTS and DPPH radicals of PKM1 seed extracts (0.48 – 1.79 mg standard equivalent per gram of dry weight) were better than those of Ang Thong and Num Phare seed extracts (0.40 – 1.13 mg standard equivalent per gram of dry weight).