2.4.1. Determination of Total Polyphenol Content
Total phenolic contents were determined according to the spectrophotometric methods of Tanner and Brunner [13]
and Kaur and Kapoor [14]. To 0.5 ml of a methanolic
solution of the extracts, 7 ml of distilled water and 0.5 ml
of Folin-Ciocalteau reagent were added and mixed well.
After 3 min, 2 ml of 20% sodium carbonate was added
and mixed well again. Absorbance of the resultant solution
was read at 720 nm, after 1 h in a water bath at 25˚C
[15]. The total polyphenol content was calculated from
the standard calibration curve obtained from catechol.