ABSTRACT
We identified a neuroprotective single fraction among 62 ones of hexane extract from Uncaria sinensis (JGH43IA) and investigated its effects and mechanisms in primary cortical neurons. Pretreatment with JGH43IA showed a significantly increase cell viability in a dose-dependent manner with a decrease in the lactate dehydrogenase release. When we performed morphological assay and flow cytometry to determination of the type of cell death, pretreatment with JGH43IA showed a significant reduction of glutamate-induced apoptotic cell death. Then we explored the downstream signaling pathways of N-methyl-D-aspartate receptor (NMDAR) with calpain activation to elucidate possible pathways of neuroprotection by JGH43IA. Pretreatment with JGH43IA exhibited a significant attenuation of NMDAR GluN2B subunit activation and a decrease in active form of calpain 1 leading to subsequent cleavage of striatal-enriched protein tyrosine phosphatase (STEP). In addition, pretreatment with JGH43IA showed a marked increase of cAMP responsive element binding protein. These results suggest that JGH43IA may have neuroprotective effects through down-regulation of NMDAR GluN2B subunit and calpain 1 activation, and subsequent alleviation of STEP cleavage. This single fraction from U. sinensis might be a useful therapeutic agent for brain disorder associated with glutamate injury.
Subject(s)
Brain Diseases , Calpain , Carrier Proteins , Cell Death , Cell Survival , Down-Regulation , Flow Cytometry , Glutamates , Glutamic Acid , L-Lactate Dehydrogenase , N-Methylaspartate , Neurons , Neuroprotective Agents , Protein Tyrosine Phosphatases , Receptors, N-Methyl-D-Aspartate , UncariaABSTRACT
OBJECTIVE: To study the chemical constituents of flavones from Uncaria sinensis. METHODS: The extract with 95% EtOH from the bard and branch with curved hooks of U. sinensis, was sequentially partitioned with petroleum ether, CHCl3, EtOAc and n-BuOH, respectively. Five flavones were isolated by column chromatography from EtOAc and n-BtOH parts, and their structures were identified by the spectral analysis of NMR and MS data. RESULTS: Five flaveones were isolated and their structures were identified as: quercetin (1), kaempferol (2), linarin (3), quercetin-3-O-β-D-galactopyranside (4), quercetin-3-O-α-L-rhamnopyranosyl-(1 → 6)-β-D-galactopyranoside (5). CONCLUSION: Compounds 1-5 were obtained from this plant for the first time. Copyright 2012 by the Chinese Pharmaceutical Association.