Quantification of Total Phenolic Content

We measured total phenolic content (TPC) with a modified version of the Folin–Ciocalteu method[13 (link)] using 0–30 mg/L chlorogenic acid as a standard. The determination of TPC was done with the colorimetric method as previously described.[13 (link)] Briefly, 100: L of sample or standard was combined with 100: L of Folin-Ciocalteu reagent and 100: L of 2% Na₂CO₃ solution. We allowed the mixture to sit for 60 min before reading absorbance at 750 nm using an Ultrospec Visible Plate Reader II 96 (GE Healthcare Ltd., England) and calculating the concentration of PSAE as chlorogenic acid equivalents per gram of dried plant seed.