Antioxidant and prooxidant activities of phenolic compounds of the extracts of Echinacea purpurea (L.)

Abstract

Growing interest exists in natural, safer antioxidants despite limited knowledge regarding echinacea's cytotoxic and oxidative potential. Total phenolics content and DPPH radical scavenging capacity were measured. Superoxide and hydroxyl radical scavenging tested electron paramagnetic resonance. Cytotoxicity screening used neutral red assay; antioxidative/prooxidative potential employed DCFDA assay on SW480 colon cancer cells exposed to varying extract concentrations (0.008-20 mg/mL) across different timeframes. The content of total phenolic compounds of extracts of E. purpurea was 10.57 % GAE. At 15.67 μg/ml concentration, extract achieved 50% radical inhibition. Echinacea demonstrated prooxidant effects at lower concentrations and shorter incubation periods, with highest concentration showing maximum toxicity after 24-hour exposure.