Antioxidant activity and HPLC analysis of Gallic acid phenolic compound from Nephelium Lappaceum leaves

Phenolic compound from Nephelium lappaceum leave was investigated using Gallic acid as a precursor. The compound was extracted from the leaves in 50, 70, 90 and 100 % methanol solvent (10:1 w/v ratio) at 60C and 75C. Based on HPLC analyses, the optimum of 71.4 mg/g of GA was extracted from green leaves in 50% methanol at 60C with FRAP value of 0.23 mM/500mg. FRAP result showed that the effect of metal chelating activity was significantly increased with increasing extract conecntration and GA was the dominant phytochemicals in the NL giving significant antioxidant activity.