食藥材萃出物及stilbenoids化合物對 Aβ 聚集所導致 PC-12 細胞凋亡之影響

Inhibition of aggregated Aβ-induced PC-12 cells apoptosis by edible plant material extracts and stilbenoids

羅喬文(Chiau-Wen Luo)

指導教授 ： 孫璐西

國立臺灣大學/生物資源暨農學院/食品科技研究所/碩士(2008年)

https://doi.org/10.6342/NTU.2008.01097

摘要

阿滋海默症 (Alzheimer's disease, AD) 是一種神經退化性疾病，病理上最大特徵是大量的老化斑塊 (senile plaques) 堆積於腦部神經細胞外，而細胞內有神經元纖維糾結 (neurofibrillary tangle) 沉積。β-amyloid peptide (Aβ )為老化斑塊的主要組成，已知Aβ 在阿滋海默症的致病過程中扮演著重要的角色。許多研究指出過多的 Aβ 聚集會導致氧化壓力 (oxidative stress)、細胞內鈣離子失衡，而促使細胞走向凋亡 (apoptosis)。本研究以「Aβ聚集導致PC-12 細胞死亡之抑制」作為阿滋海默症之細胞模式 ，篩選一些具有抗氧化功效以及預防或延緩阿滋海默症之功效的食藥材。將桑椹水萃物、洛神花水萃物和蓮子心 70% 甲醇粗萃物以及源自於何首烏 (Polygonum multiflorum Thunb.) 的 2,3,5,4'-tetrahydroxystilbene-2-O-β-gluco pyranoside (PM-SG) 和 許多漿果中存在的 pterostilbene 進行體外抗氧化能力測定與其抑制 Aβ25-35 毒性作用之功效，結果顯示蓮子心 70% 甲醇粗萃物的抗氧化能力和保護 PC-12 細胞免於 Aβ25-35 毒性的效果最好。因此將蓮子心 70% 甲醇粗萃物進一步以不同溶劑區分，得到正己烷區分物 (Nn-M-H)、乙酸乙酯區分物 (Nn-M-EA)、正丁醇區分物 (Nn-M-B) 和水區分物 (Nn-M-W)，將此四個區分物進行體外抗氧化能力測定和抗 Aβ1-40

關鍵字

阿滋海默症 ； 類澱粉蛋白 ； PC-12 ； 氧化壓力 ； 蓮子心 ； stilbenoids

並列摘要

Alzheimer's disease (AD), the major cause of dementia, is a neurodegenerative disorder associated with impairment in memory and cognitive function. AD is characterized pathologically by the presence of senile plaques (amyloid plaques), and neurofibrillary tangles (NFT). β-amyloid peptide (Aβ) has been proposed to play an important role in the pathogenesis of AD. Deposits of Aβ are found in the brains of patients with AD and are one of the pathological hallmarks of the disease. Many studies have shown that aggregated Aβ can induce caspase-dependent apoptosis and death by oxidative stress and increase intracellular calcium levels in cultured neurons. The aim of my study is to investigate the antioxidative activities and neuroprotective effects of some edible plant extracts and stilbenoids.
The antioxidative potency was evaluated by DPPH radical scavenging activity and trolox equivalent antioxidant capacity (TEAC). The neuroprotective activity was evaluated in vitro in the “Aβ-induced cell death of rat pheochromocytoma (PC-12) cells” model system. Among the different samples (mulberry, roselle and the embryo of Nelumbo nucifera Gaertn. seed extracts), methanol extract of the embryo of Nelumbo nucifera GAERTN. seed (Nn-M) showed better antioxidative activity and also higher inhibitory effect against Aβ25-35 –induced cytotoxicity. Therefore, Nn-M was fractionated into n-hexane, ethyl acetate, n-butanol and aqueous fractions. The n-butanol fraction of Nn-M was found to have the best inhibitory effect against Aβ1-40 –induced cytotoxicity. Among stilbenoids, stilbene glycoside purified from Polygonum multiflorum Thunb. (PM-SG) has better inhibitory effect against Aβ25-35 –induced and Aβ1-40 –induced cytotoxicity than pterostilbene.
The mechanism of the possible protective action of PM-SG and n-butanol fraction of Nn-M was further investigated. Results showed that Aβ1-40 signficantly increased ROS level, intracellular [Ca2+] and caspase-3 activity, and also signficantly decreased mitochondrial membrane potential and glutathione content in PC-12 cells. PM-SG and n-butanol fraction of Nn-M showed a significant reduction of the elevated ROS, intracellular [Ca2+] and caspase-3 activity and also replenished the loss of mitochondrial membrane potential and glutathione content induced by Aβ1-40. This study concludes that PM-SG and n-butanol fraction of Nn-M have potential neuroprotective ability against Aβ-mediated cell damage.

並列關鍵字

Alzheimer’s disease ； β-Amyloid peptide ； PC-12 ； Oxidative stress ； Embryo of the seed of Nelumbo nucifera GAERTN. ； Stilbenoids

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