Appropriately 1 ml of diluted solution
(20–50 fold dilution) was added with 0.2 ml of two-fold
diluted Folin–Ciocalteu reagent and mixed thoroughly. After
3 min, 3 ml of 2 % (w/v) sodium carbonate solution were
added. After the solution was left for 30 min at room temperature,
an absorbance was measured at 760 nm using a UV-
1601 spectrophotometer (Shimadzu, Kyoto, Japan). The concentration
of total phenolic compounds was calculated from
the standard curve of gallic acid with the range of 0–0.05 mg/
ml and expressed as g GAE/100 g extract.