2.3. Determination of total phenolic content (TPC) in Senjed peel aqueous extracts
Total phenolic compounds in the extracts were determined, using Folin–Ciocalteau reagent, by the method of Hussain et al. (2018) and expressed as mg/g of Gallic acid equivalents (GAE) as a standard. 0.5 mL of extracts (at a concentration of 1–10 mg/mL extracts in water) was mixed with 2.5 mL of 10% Folin-Ciocalteu reagent and 2 mL of 7.5% sodium carbonate solution. After the samples were kept for 30 min at room temperature for incubation, the absorbance was measured at 760 nm in a UV/visible spectrophotometer (Ultrospec 2000; Pharmacia Biotech Ltd., Cambridge, UK).