Similar potency of catechin and its enantiomers in alleviating 1-methyl-4-phenylpyridinium ion cytotoxicity in SH-SY5Y cells.

OBJECTIVES: Previously, the flavonoid (±)-catechin was shown to exert potent neuroprotective action in the mouse 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine-induced Parkinson's disease model. The purpose of this study was to investigate whether the different enantiomers of catechin ((+)-catechin, (-)-catechin and (±)-catechin, a 50:50 mixture of (+)-catechin and (-)-catechin) could protect SH-SY5Y cells against 1-methyl-4-phenylpyridinium ion (MPP(+) ) toxicity by decreasing the generation of oxygen free radicals. The inhibitive effect of (±)-catechin on JNK/c-Jun activation was investigated. METHODS: The effects of (+)-catechin, (-)-catechin or (±)-catechin in protecting against MPP(+) toxicity were evaluated and compared in SH-SY5Y cells by testing the release of lactate dehydrogenase. The generation of reactive oxygen species (ROS) was measured by immunochemistry and the phosphorylation level of JNK/c-Jun was determined by Western blotting. KEY FINDINGS: In SH-SY5Y cells, (+)-catechin, (-)-catechin or (±)-catechin reduced apoptosis induced by MPP(+) and decreased ROS generation caused by MPP(+) . Different enantiomers of catechin showed protective effects at similar potency. Moreover (±)-catechin decreased JNK/c-Jun phosphorylation which was increased by MPP(+). CONCLUSIONS: Catechin and its two enantiomers could protect SH-SY5Y cells against MPP(+) cytotoxicity at a similar potency. Antioxidative stress and inhibition of the JNK/c-Jun signalling pathway might have been involved in the neuroprotective mechanisms of catechin against MPP(+) cytotoxicity in SH-SY5Y cells.

[Isolation and identification of Suavissimoside R1 from roots of Rubus parvifollus used for protecting dopaminergic neurons against MPP+ toxicity].

OBJECTIVE: Suavissimoside R1 was isolated and identified as an active ingredient from Roots of Rubus parvifollus L, which exhibited protective effect on dopaminergic neurons against MPP+ toxicity. METHODS: The protective effects of crude extracts were investigated after mice were treated with 1-methyl4-phenyl-1,2,3,6-tetrahydropyridine (MPTP). According to the protective effects of crude extracts, suavissimoside R1, one kind of triterpenoid saponin, was separated. It was investigated that whether Suavissimoside R1 can protect DA neurons from toxicity induced by MPP+ in rat mesencephalic cultures. RESULTS: Suavissimoside R1 was isolated from Roots of Rubus parvifollus L. Moreover, Suavissimoside R1, in dose of 100 micromol/L, alleviated the death of DA neurons induced by MPP+ obviously. CONCLUSION: These results suggest that suavissimoside R1 possesses potent neuroprotective activity and can be developed to be a potential anti-Parkinson's disease drug worthy for further study.