In-vitro Evaluation of Antioxidant Potency of Organic Extracts of Leaves of Corchorus depressus Linn.

Aim: Evaluation of free radical scavenging and lipid peroxidation inhibitory activities of commercially available leaves of Corchorus depressus Linn. by in-vitro chemical analysis.

Methodology: Four different solvent extracts methanol-CDM, ethanol-CDE, ethyl acetate-CDEA and hexane-CDH were studied for their free radical scavenging activities using 1-diphenyl-2-picrylhydrazyl (DPPH) radical assay method and the results were expressed as SC50 values. The lipid peroxidation inhibitory activities of three different concentrations (0.1, 0.5 and 1.0 mg/mL) were evaluated using b-carotene-linoleic acid model system and the results were expressed as oxidation rate ratio (ROR), antioxidant activity (AA) and antioxidant activity coefficient (CAA). L-Ascorbic acid-AA, a-tocopherol-TOC and BHT were used as reference compounds. The total polyphenol contents of these extracts were also determined using Folin-Ciocalteau reagent.

Results: The total polyphenol contents of extracts were decreased in the order of: CDM > CDE > CDEA >> CDH. In DPPH radical assay, CDM exhibited higher free radical scavenging activity (SC50: 216.27 µg/mL) than CDE (327.84 µg/mL) and CDEA (544.28 µg/mL). In comparison with natural antioxidants AA and TOC, the overall ranking was decreased in the order of: AA > CDM > TOC > CDE > CDEA >> CDH. In b-carotene-linoleic acid model system, CDM also exhibited higher protective activity against lipid peroxidation than other extracts as it exhibited lower ROR (0.4903 to 0.2752) and higher AA (50.96 to 72.47) and CAA (280.58 to 513.13) respectively amongst the studied extract. In comparison with BHT and TOC, CDM exhibited promising potency than TOC. Amongst the studied concentration 0.5 and 1.0 mg/mL were the mostly potent antioxidant against oxidation of linoleic acid.

Conclusion: CDM exhibited most propitious antioxidant activities irrespective of the method undertaken in this study. CDM and CDE had protective activity against oxidation of fatty acid as well as both efficiently scavenged free radicals.