Determination of the antioxidant property from the flavonoid rich subextract of Clitoria ternatea

This study evaluated the phytochemical, total phenolic and flavonoid content, and antioxidant property of the Clitoria ternatea flower extract using, 2-diphenyl-1picrylhydrazyl (DPPH) free radical scavenging activity. Clitoria ternatea flower sample were collected from Herbanext Laboratories Inc., was oven dried at 60oC for 6hrs, then macerated using 70% ethanol and concentrated using a rotary evaporator at 600C to obtain a syrupy crude extract, the sample was subjected to phytochemical screening to check for the presence of flavonoids and phenols, and was further used for sub-extraction using water, n-hexane and ethyl acetate as partitioning solvents and analyzed for its total phenolic and flavonoid content. The sub-extract with the highest concentration of phenols and flavonoids were then subjected to DPPH free radical scavenging activity. The results revealed that among the 3 sub-extracts subjected to total phenolic and total flavonoid content, the ethyl acetate (174.60 ± 5.32 mg GAE/g & 347.27 ± 8.79 mg QE/g) sub-extract has the highest concentration, compared to the aqueous (42.34 ± 1.84 mg GAE/g & 29.49 ± 5.28 mg QE/g) and n-hexane (15.14 ± 0.99 mg GAE/g & 272.42 ± 2.29 mg QE/g) sub-extracts, the flavonoid rich sub-extract was then subjected to antioxidant assay using the DPPH free radical scavenging activity, the result showed that the extract exhibits concentration dependent activity with an IC50 value of 75.13 ± 3.14 ppm compared to the standard gallic acid (1.74 ppm). Further investigation using different parts of the plant and various purification methods are recommended to confirm the potential use of Clitoria ternatea as potential source of antioxidant compound and maximize its use.