Total Phenolics and Flavonoids

Total phenolics and flavonoids contents were extracted with pure methanol at room temperature for 48 h. After filtration of the extracts and evaporation of the methanol, the resulting precipitate was dissolved in 4 mL of distilled water or pure methanol. The aqueous (phenolics) and methanolic (flavonoid) extractions were used for analysis.

Total phenolics content of the aqueous extract was measured by a method involving Folin-Ciocalteu reagent and gallic acid (GAE) standard at 765 nm (Pourmorad et al. 2006). The amount of total phenolics was expressed as mg GAE equivalent g⁻¹ DW.

Flavonoid content was determined by Chang et al. (2002) using the aluminum chloride method at 415 nm. The standard curve was prepared at concentrations 0–200 µg mL⁻¹ quercetin and the flavonoid content was reported as mg quercetin equivalent g⁻¹ DW.