Total phenolic content was assayed by the Folin–Ciocalteu
colorimetric method with slight modification Briefly, aliquots (1.0 mL) of appropriately diluted
extracts or standard solutions were mixed with 0.5 mL 0.5 N
Folin–Ciocalteu reagent, then the reaction was neutralized with
saturated sodium carbonate (75 g/L). The absorbance of the
resulting blue color was recorded using a spectrophotometer after
incubation for 2 h at 23 C. A calibration curve was prepared using
gallic acid solution. Total phenolics contents were expressed as
milligrams of gallic acid equivalent (mg GAE) per 100 g of dry
weight.