Extractive determination of bioactive flavonoids from butterfly pea ( Clitoria ternatea Linn.)

Recently, in the field of natural product drug discovery, there has been increasing interest in effective extraction and isolation of bioactive phytomolecules from plants for use as important starting materials or chemical intermediates for new drug development. In this investigation, various solvent extracts of butterfly pea (Clitoria ternatea Linn.) were evaluated in terms of phenolic content and antioxidant activity. Moreover, various parameters influencing optimal flavonoid extraction were studied based on determination of the quercetin and kaempferol yields by an improved high- performance liquid chromatography (HPLC) method. The results indicated that the total phenolics and 2,2 0 -azino-bis-3-ethylbenzothiazoline-6-sulfonic acid (ABTS) scavenging activity were maximum for the 80 % aqueous methanol extract, while the 1,1-diphenyl- 2-picrylhydrazyl (DPPH) reducing power and flavonoid content were maximum in the methanol extract. Different solvent extracts showed significantly (p\0.05) different phytochemical yield and antioxidant capacity. Furthermore, the total phenol and flavo- noid contents revealed good (p\0.001) correlations with scavenging potency. The maximum flavonoid content was found for methanol concentration, time, temperature, and solid-to-liquid ratio of 80 %, 60 min, 80 � C, and 1:20 g/mL, respectively. It is concluded that butterfly pea leaf can be considered a potential source of flavonoids with good antioxidant properties for use in dietary applications. The extraction protocols developed in this study can be readily scaled up for industrial applications.