In vitro Antioxidant Potential of Euclea crispa (Thunb.) Leaf Extracts

Background: Euclea crispa is a South African medicinal plant belonging to the family Ebenaceae. Objectives: The objective of this study was to analyze the in vitro antioxidant activity of different extracts of E. crispa leaves. Materials and Methods: 2, 2‑diphenyl‑1‑picrylhydrazyl (DPPH) radical scavenging assay, reducing power assay, ferric reducing antioxidant power (FRAP) assay, hydroxyl scavenging assay, and nitric oxide scavenging assay were used to analyze free‑radical scavenging activity. The superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPX), total reduced glutathione (TRG), and estimation of vitamin C assays were carried out to analyze the enzymatic and nonenzymatic antioxidants on a fresh leaf of E. crispa. Results: The DPPH radical scavenging assay (135.4 ± 0.7 μg/ml), hydroxyl scavenging assay (183.6 ± 0.9 μg/ml), and nitric oxide scavenging assay (146.2 ± 1.3 μg/ml) showed the significant half maximal inhibitory concentration (IC₅₀) values in ethanolic extract when compared to the ethyl acetate, chloroform, and petroleum ether extract of E. crispa leaves. Further, the ethanolic extract exhibited good reducing power assay and FRAP assay showed (the maximum absorption of 0.79 and 0.68 at 500 μg/ml, respectively) when compared to other solvent extracts. The fresh E. crispa leaves possess high content of enzymatic and nonenzymatic antioxidants such as SOD (41.3 ± 0.34 units/mg protein), CAT (124 ± 0.54 μmole of H₂O₂ consumed/min/mg protein), GPX (261.2 ± 0.42 μg of glutathione oxidized/min/mg protein), TRG (42.3 ± 0.16 μg/mg protein), and estimation of vitamin C (185 ± 0.39 μg/mg) assays. Conclusion: Based on the results obtained from this study, it can be concluded that the E. crispa leaves can be used for the preparation of antioxidative therapeutic agents. However, further studies are necessary to substantiate the current findings.