title: Cytoprotective effects of Lycium barbarum against reducing stress on endoplasmic reticulum.
abstract: Chinese medicinal herbs have been consumed for thousands of years for the purpose of healthy aging. Lycium barbarum is valued in Chinese culture for its benefits to anti-aging, vision, kidney and liver. Recent studies showed that extracts from L. barbarum possess biological activities including anti-aging, anti-tumor, immune-stimulatory and cytoprotection. Most of these studies emphasized that the protective function of L. barbarum is due to its anti-oxidative effects. We have previously demonstrated that extract from L. barbarum can protect neurons against beta-amyloid (Abeta) peptide-induced apoptosis. Since Abeta toxicity may be mediated via oxidative stress, it is still unclear whether the extract from L. barbarum is a simple anti-oxidant exhibiting cytoprotective effects. We hypothesized that extract from L. barbarum is not simply an anti-oxidant in order to function as a neuroprotective agent. The aim of this study is to investigate whether the extract from L. barbarum (LBG) protect neurons via mechanisms independent of anti-oxidative effects. Using a reducing agent, dithiothreitol (DTT), we found that LBG exhibits cytoprotective effects against reducing stress by lowering the DTT-induced LDH release and caspase-3 activity. DTT can trigger endoplasmic reticulum (ER) stress leading to PKR-like ER kinase (PERK) activation. We also showed that LBG attenuates DTT-induced PERK phosphorylation. The extract from L. barbarum is not simply an anti-oxidant; it can also exhibit cytoprotective effects against reducing stress by DTT.
authors: Laboratory of Neurodegenerative Diseases, Department of Anatomy, The University of Hong Kong, SAR.
authors: Man-Shan
authors: MS
authors: Yu
authors: Yuen-Shan
authors: YS
authors: Ho
authors: Kwok-Fai
authors: KF
authors: So
authors: Wai-Hung
authors: WH
authors: Yuen
authors: Raymond Chuen-Chung
authors: RC
authors: Chang