Antioxidant Profiling of Plant Extracts

Total antioxidant capacity (ferric reducing antioxidant power, FRAP) was extracted in ice-cold 80% ethanol using a MagNALyser (Roche, Vilvoorde, Belgium) and measured using Trolox as a reference [55 (link)]. Plant materials were extracted in 1mL 80% ethanol using MagNALyser for ascorbate and glutathione measurement (Roche, Vilvoorde, Belgium). HPLC was used to measure reduced ascorbate (ASC) and reduced glutathione (GSH). Total ascorbate (ASC + DHA) and glutathione (GSH + GSSG) concentrations were evaluated after dithiothreitol (DTT) reduction, as previously reported [13 (link)]. Polyphenols and flavonoids were extracted by homogenizing fresh plant materials in 80% ethanol and centrifuged for 15 min at 5000 rpm. The clear extract was then used to determine the total phenolic and flavonoid content using the Folin-Ciocalteu and aluminum chloride tests.