Quantification of flavonoid in aqueous extract of the leaves of Phaseolus vulgaris linn. by RP-HPLC and study of antioxidant potential by DPPH assay

This study aimed to develop a method for quantifying flavonoids present in the aqueous extract of Phaseolus vulgaris Linn. leaves and assessed the antioxidant potential of the crude extract. To investigate the phytoconstituents and pharmacological properties of the crude aqueous extract of the leaves, a sequential extraction approach was utilized. For more effective secondary metabolite separation, (RP-HPLC) reverse phase high-performance liquid chromatography is employed. A Hemochrom C18 column (150mm in length × 4.6mm in diameter, 5μm) was used. A readily available Photodiode array (PDA) detector was used to measure the UV absorption of a peak. RP-HPLC was used to quantify polar components. DPPH(2,2-diphenyl-1-picrylhydrazyl) assay of crude aqueous extract has IC50 = 129.7±0.03μg/ml i.e. 50% inhibition at this concentration. In contrast, standard ascorbic acid (IC50 = 14.27±0.068μg/ml), 129.7μg of sample 1 were found equivalent to 14.27μg of ascorbic acid. Therefore, plant components must be isolated and purified from aqueous extracts to assess their antioxidant capacity, as they are eco-friendly and inexpensive solvents. Furthermore, the DPPH radical scavenging ability of the isolated compounds must be studied to understand their antioxidant potential. The isolated compound can be used in new drug formulations; hence, the quantification, isolation, and characterization of flavonoids is essential.