ANTIOXIDANT ACTIVITY AND LIPOXYGENASE INHIBITION OF HYDROCOTYLE NEPALENSIS

Seok Hyeon Moon and Man Kyu Huh*

ABSTRACT

Objective: The objectives of this study were to determine antioxidant activities and lipoxygenase inhibition of ethanol extracts of Hydrocotyle nepalensis (Araliaceae) leaves and stems. Materials and Methods: The hydroxyl radical (-OH) can damage virtually all types of macromolecules: carbohydrates, nucleic acids (mutations), lipids (lipid peroxidation), and amino acids. The 1, 1- diphenyl 2-picrylhyorazyl (DPPH) is a well-known radical and a trap (scavenger) for other radicals. Results: The antioxidant activity of the H. nepalensis extracts was measured on the basis of the scavenging activity of the –OH and DPPH free radical. Hydroxyl radical scavenging activity of H. nepalensis was 78.8%. DPPH scavenging activity of leaves of H. nepalensis was evaluated at 8.0 mg/ml was 96.8%. Lipoxygenases (LOXs) constitute a heterogeneous family of lipid peroxidizing enzymes capable of oxygenating polyunsaturated fatty acids to their corresponding hydroperoxy derivatives. The inhibitory effect of 15-LOX by H. nepalensis was assayed using a Morgan microplate assay. The extract of H. nepalensis was 67.6% inhibitory effects on the activation of LOX. The IC50 values for OH activity, DPPH activity, and LOX inhibition were 14.61 μg/ml, 5.26 μg/ml, and 31.27 μg/ml, respectively. Conclusion: These results show that H. nepalensis has some phytochemical constituents which may be active against the free radicals (OH and DPPH) and lipoxygenase enzyme.

Keywords: Antioxidant activities, hydroxyl radical, 1, 1- diphenyl 2-picrylhyorazyl (DPPH), Hydrocotyle nepalensis, lipoxygenase.