title: Antioxidant properties and protective effects of a standardized extract of Hypericum perforatum on hydrogen peroxide-induced oxidative damage in PC12 cells.
abstract: Free radical scavenging and antioxidant activities of a standardized extract of Hypericum perforatum (SHP) were examined for inhibition of lipid peroxidation, for hydroxyl radical scavenging activity and interaction with 1,1-diphenyl-2-picrylhydrazyl stable free radical (DPPH). Concentrations between 1 and 50 microg/ml of SHP effectively inhibited lipid peroxidation of rat brain cortex mitochondria induced by Fe2+/ascorbate or NADPH system. The results showed that SHP scavenged DPPH radical in a dose-dependent manner and also presented inhibitory effects on the activity of xanthine oxidase. In contrast, hydroxyl radical scavenging occurs at high doses. The protective effect of the standardized extract against H2O2-induced oxidative damage on the pheochromocytoma cell line PC 12 was investigated by measuring cell viability via 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT), lactate dehydrogenase (LDH) assays, caspase-3-enzyme activity and accumulation of reactive oxygen species [2',7'-dichlorofluorescin (DCF) assay]. Following 8-h cell exposure to H2O2 (300 microM), a marked reduction in cell survival was observed, which was significantly prevented by SHP (pre-incubated for 24 h) at 1-100 microg/ml. In a separate experiment, different concentrations of the standardized extract (0.1-100 microg/ml) also attenuated the increase in caspase-3 activity and suppressed the H2O2 -induced reactive oxygen species generation. Taken together, these results suggest that SHP shows relevant antioxidant activity both in vitro and in a cell system, by means of inhibiting free radical generation and lipid peroxidation.
authors.affiliation: Departamento de Farmacología, Facultad de Farmacia, Universidad Complutense, Plaza Ramon y Cajal sn. 28040 Madrid, Spain. jbenedi@farm.ucm.es
authors.forename: Juana
authors.initials: J
authors.lastname: Benedí
authors.forename: Rocio
authors.initials: R
authors.lastname: Arroyo
authors.forename: Carmen
authors.initials: C
authors.lastname: Romero
authors.forename: Sagrario
authors.initials: S
authors.lastname: Martín-Aragón
authors.forename: Angel M
authors.initials: AM
authors.lastname: Villar
mesh_terms: D000818:Animals; D000975:Antioxidants / Q000737:chemistry / Q000378:metabolism / Q000494:pharmacology*; D017209:Apoptosis / Q000187:drug effects; D001713:Biphenyl Compounds / Q000378:metabolism; D002470:Cell Survival / Q000187:drug effects; D002540:Cerebral Cortex / Q000187:drug effects / Q000378:metabolism; D004305:Dose-Response Relationship, Drug; D016166:Free Radical Scavengers; D006834:Hydrazines / Q000378:metabolism; D006861:Hydrogen Peroxide / Q000633:toxicity*; D020902:Hypericum / Q000737:chemistry; D015227:Lipid Peroxidation / Q000187:drug effects*; D008928:Mitochondria / Q000187:drug effects / Q000378:metabolism; D016716:PC12 Cells / Q000187:drug effects* / Q000378:metabolism / Q000473:pathology; D010851:Picrates; D010936:Plant Extracts / Q000737:chemistry / Q000378:metabolism / Q000494:pharmacology*; D051381:Rats; D017382:Reactive Oxygen Species / Q000378:metabolism; D014969:Xanthine Oxidase / Q000037:antagonists & inhibitors / Q000378:metabolism
chemical_list: D000975:Antioxidants; D001713:Biphenyl Compounds; D016166:Free Radical Scavengers; D006834:Hydrazines; D010851:Picrates; D010936:Plant Extracts; D017382:Reactive Oxygen Species; D006861:Hydrogen Peroxide; C004931:1,1-diphenyl-2-picrylhydrazyl; D014969:Xanthine Oxidase