The TPC was quantified by the Folin-Ciocalteau method (17 (link)) with some modifications. Briefly, 200 μl of properly diluted samples or standard were mixed with 100 μl of Folin-Ciocalteau reagent. After 5 min, 300 μl of Na2CO3 (7.5%, w/v) and 1.0 ml of water were added. After 30 min, the absorbance at 765 nm was measured using a microplate reader (Biotek, Vermont, USA). The TPC was calculated based on the calibration curve plotted using gallic acid (0–200 μg/ml) and the results were expressed as μg of gallic acid equivalents per gram of extract [(μg GAE)/g E].
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