Total phenolic content (TPC) in O. crenata and S. minor extracts
was determined spectrophotometrically using the Folin-Ciocalteu
method. Briefly, an aliquot of each diluted extract was mixed with
0.5 mL of Folin-Ciocalteu reagent; after 3 min, 1 mL of sodium
carbonate solution (20% w/v) was added to the reaction mixture.
The solution was incubated at 40 C for 20 min and cooled under
running tap water; the absorbance was then measured at 750 nm
using a Cary 50 UV–vis spettrophotometer (Varian Inc., Palo Alto,CA, USA). Caffeic acid was used as reference standard to estimate
TPC in the sample. TPC was expressed as mg of caffeic acid
equivalent (CAE) per gram of DM.