RP-HPLC with UV detection was employed for the analysis of phenolic compounds. Total phenolic compounds were determined by the Folin–Ciocalteu assay.
The amount of extractable phenolic substances for this method decreased with decreasing polarity of the solvent in the order water, 60% methanol, 60% acetone, and ethyl acetate/water (60:30, v/v) by using the conventional method.