Gallic acid was used as a standard with varied
concentration from 100 ppm to 500 ppm. Both
samples and standards were mixed with Folin-
Ciocalteu reagent (1:1), 7.5% (w/v) sodium
carbonate and diluted with water before observed
under UV-Vis spectrophotometer at 760 nm
absorbance. Each measurement was repeated five
times and TPC was expressed as mg Gallic acid
equivalent per gram extract weight (mg GAE/g
extract weight)