The total phenolic content (TPC) of each fraction was determined
using the Folin–Ciocalteu method with some modifications
(Liu & Yao, 2007). Briefly, 200 ll of extract solution was shaken for
1 min with 1 ml of diluted (1:10 with water) Folin–Ciocalteu reagent.
After the mixture was shaken, 800 ll of 10% Na2CO3 was
added, and final volume was made up to 5 ml with distilled water.
After 2 h of reaction, the absorbance at 760 nm was determined
and used to estimate the phenolics-acid content using a standard
curve prepared using gallic acid.