Purification, chemical structure and antioxidant activity of active ingredient (LPT-3d) separated from Lachnum sp.

Abstract

Abstract The current work was aimed to elucidate the structure of a yellow pigment LPT-3d from Lachnum sp. fermentation broth and antioxidant activities were discussed using H2O2-induce HepG2 cells. Based on UV–vis, FT-IR, HR-ESI-MS, NMR analysis, the yellow pigment was identified as a tetracyclic triterpenoid: methyl 2-(3-ethyl-4-methyl-4-nitroimidazolidin-1-yl)-6,6,9,9a,11a-pentamethyl-1-(3-methyl-4,5-dihydro-3H-pyrazol-4-yl)-7,10-dioxo-8-(propionyloxy)hexadecahydronaphtho[1′,2′:6,7]indeno[1,7a-b]oxirene-5-carboxylate. The scavenging ability of DPPH was 95.65 ± 0.51% (1000 μg mL−1), and the IC50 value of reducing power was 74.01 ± 0.34 μg mL−1. HepG2 cell injury induced by H2O2 (300 μM) for 2 h, the cell viability was 49.50% examined by MTT assay. The cell viabilities of LPT-3d treated groups (at the concentrations of 10, 20, 50 μg mL−1) were 64.89%, 66.57% and 81.71% respectively. LPT-3d treated HepG2 cell at the contention of 50 μg mL−1 showed the activities of SOD and CAT were 39.98 ± 3.02 U mg−1, 9.94 ± 1.36 U mg−1, and the level of MDA was 2.12 ± 0.06 mg mg−1 of protein. Compared with the control group, LPT-3d presented higher antioxidant activity and protective effect on H2O2-induced injury to HepG2 cells. The results suggested that Lachnum sp. triterpenoid yellow pigment had a potential application for the treatment of oxidative stress related hepatic diseases.