Two-Step Chronoamperometric Determination of Antioxidant Capacity of Water Extracts from Medicinal Plants

Medicinal plants contain a wide range of bioactive compounds including antioxidants.Thus, the evaluation of the antioxidant capacity of medicinal plant extracts used in phytotherapy is of practical interest.Water extracts from 11 plants obtained by sonication for 30 min were studied by cyclic voltammetry at bare glassy carbon electrode (GCE) and GCE modified with a mixture of 1 mg mL -1 CeO 2 and SnO 2 nanoparticles (NPs) dispersed in 0.10 mM cetylpyridinium bromide.A two-step chronoamperometric approach (at 400 and 900 mV for 75 s each one) was developed to estimate the antioxidant capacity of medicinal plant extracts.A strong and very strong correlation level was obtained between the antioxidant capacity and total phenolic contents or antioxidant capacity toward 2,2-diphenyl-1-picrylhydrazyl (DPPH ).