Antioxidant Activities and Total Phenolic Content of Multi-colored Fruits and Vegetables in Thailand

Fruits and vegetables are valuable sources of natural phenolic antioxidants which are known to have beneficial health promoting properties. The main objectives of this study were to compare the antioxidant activities and total phenolic and flavonoid contents of ten ethanolic edible plant extracts (Five species of  fruits and vegetables) with varieties of colors.The result showed that purple color of plants, including ethanolic extracts of Brassica oleracea Linn. (40.7±0.56%) and Vigna sesquipedalis (4.52±0.01%) significantly showed the highest TPC and TFC compared with the same species and other species with different colors (p<0.01). Measurement of antioxidant capacity, yellow Capsicum annuum Linn. (58.72±0.52%) and purple Solanum melongena Linn. extract (22.44±1.20%) significantly showed the maximum antioxidant activities by DPPH radical scavenging activity assay and ferric ion reducing antioxidant power (FRAP) assay, respectively (p<0.01). Base on shades of color pigment extracts, green and red pigment had more potential antioxidant activities than other colors. The purple and yellow pigments showed the maximum total phenolic contents by Folin-Ciocalteu reagent. These results  concluded that purple color of plants; Brassica oleracea Linn. and Vigna sesquipedalis in this study had the potential to be a suitable source of cheap phenolics and flavonoids as antioxidant compounds.