Department of Korean Medical Science, School of Korean Medicine, Pusan National University, Yangsan 626-870, Republic of Korea.
J Ethnopharmacol. 2013 Oct 28;150(1):108-15. doi: 10.1016/j.jep.2013.08.014. Epub 2013 Aug 22.
Dried roots of Polygonum multiflorum have traditionally been used in the retarding of aging process in East Asian countries and its extracts exhibit anti-oxidative activities.
Neuroprotective effects of ethyl acetate extract from Polygonum multiflorum (EEPM) were investigated against glutamate-induced oxidative cell death in HT22 hippocampal cells. Cell viability, cytotoxicity, morphological, flow cytometry, and Western blot assays were performed in order to observe alterations of neuronal cell survival or death related pathways.
Pretreatment with EEPM resulted in significantly decreased glutamate-induced neurotoxicity and also resulted in drastically inhibited glutamate-induced apoptotic and necrotic neuronal death. To elucidate possible pathways of neuroprotection by EEPM, we explored the activation of mitogen activated protein kinases (MAPKs), phosphatidylinositol-3-kinase, and cAMP responsive element binding protein (CREB). Treatment with glutamate alone led to activation of extracellular regulated kinase (ERK), Jun N-terminal kinase, and p38 during the late phase after glutamate exposure, but pretreatment with EEPM resulted in significantly attenuated activation of these proteins. Pretreatment with EEPM resulted in increased activation of CREB. The specific inhibitors of ERK and p38, PD98059 and SB203580, abrogated the neuroprotective effects of EEPM. When we evaluated calpain I and striatal-enriched protein tyrosine phosphatase (STEP), active form of calpain I was significantly increased after glutamate exposure, and, along with this, active form of STEP showed a decrease. Pretreatment with EEPM resulted in significant recovery of pro-calpain I and active form of STEP caused by glutamate. Co-treatment with calpain inhibitor ALLN and EEPM had a synergistic effect on neuronal death and contributed to blockade of activation of both ERK and p38 with increased activation of CREB.
These results suggest that Polygonum multiflorum extract may have neuroprotective effects through both alleviation of ERK and p38 activation with increased activation of CREB under oxidative stress and has potential as a therapeutic intervention for treatment of oxidative neuronal death.
传统上，东亚国家使用何首乌的干根来延缓衰老过程，其提取物具有抗氧化活性。
研究了何首乌乙酸乙酯提取物（EEPM）对 HT22 海马细胞中谷氨酸诱导的氧化细胞死亡的神经保护作用。为了观察神经元细胞存活或死亡相关途径的变化，进行了细胞活力、细胞毒性、形态学、流式细胞术和 Western blot 分析。
EEPM 预处理可显著降低谷氨酸诱导的神经毒性，并显著抑制谷氨酸诱导的凋亡和坏死性神经元死亡。为了阐明 EEPM 神经保护的可能途径，我们探讨了丝裂原活化蛋白激酶（MAPKs）、磷脂酰肌醇-3-激酶和 cAMP 反应元件结合蛋白（CREB）的激活。单独用谷氨酸处理会导致谷氨酸暴露后晚期细胞外调节激酶（ERK）、Jun N-末端激酶和 p38 的激活，但 EEPM 预处理会显著减弱这些蛋白的激活。EEPM 预处理会增加 CREB 的激活。ERK 和 p38 的特异性抑制剂 PD98059 和 SB203580 会消除 EEPM 的神经保护作用。当我们评估钙蛋白酶 I 和纹状体丰富的蛋白酪氨酸磷酸酶（STEP）时，谷氨酸暴露后钙蛋白酶 I 的活性形式明显增加，同时 STEP 的活性形式减少。EEPM 预处理可显著恢复谷氨酸引起的原钙蛋白酶 I 和 STEP 活性形式的恢复。钙蛋白酶抑制剂 ALLN 与 EEPM 联合处理对神经元死亡具有协同作用，并通过增加 CREB 的激活来阻断 ERK 和 p38 的激活。
这些结果表明，何首乌提取物可能通过在氧化应激下减轻 ERK 和 p38 的激活并增加 CREB 的激活来发挥神经保护作用，并具有作为治疗氧化神经元死亡的治疗干预的潜力。
