Estimation of Total Polyphenolic Content
Total polyphenolic content of the plant extracts was estimated
using microplate assay method modified from standard procedure
using Folin-Ciocalteu reagent [19]. 20 ml each of the 10 mg/ml
extracts in methanol and the serial gallic standard solutions in
methanol were loaded on a 96 well microplate. Then 100 ml of
Folin-Ciocalteu reagent was added to each well, mixed well and
waited for 5 min. Again 80 ml of 7.5% sodium carbonate solution
was added and mixed well. After covering and keeping it in the
dark for 2 hrs, absorbance at 750 nm was measured using Tecan
Infinite M 200 microplate reader. Total polyphenols were
determined using the standard curve obtained for gallic acid.
The estimation of the phenolic compounds in each of the extract
was performed in triplicate and the results were expressed as mg of
gallic acid equivalents (GAE) per g of dry plant part.