探讨龙眼果肉醇提物的石油醚相（LP）和水相（LW）对小鼠学习记忆功能的改善效果及作用机制。以SAMP8小鼠为老年痴呆模型，采用Morris水迷宫观察小鼠的学习记忆能力；检测小鼠血清中一氧化氮（NO）、丙二醛（MDA）和谷胱甘肽（GSH）含量及超氧化物歧化酶（SOD）和谷胱甘肽过氧化物酶（GSH-Px）活力；Western blot法检测小鼠脑组织中β-淀粉样蛋白（Aβ1-42）等相关蛋白（淀粉样前体蛋白（APP）、β-淀粉样前体蛋白裂解酶1（BACE1））的表达水平。研究发现，与模型组相比，LP和LW能显著改善痴呆小鼠的学习记忆功能，分别不同程度地降低其血清中NO和MDA含量以及脑组织中Aβ1-42、APP和BACE1的蛋白表达，提高其血清中SOD和GSH-Px活力。以上结果表明LP和LW可能通过提高小鼠机体的抗氧化能力和抑制其脑组织中Aβ等相关蛋白的表达的共同作用来改善痴呆小鼠的学习记忆功能，具有预防老年痴呆症的潜在功效。

The effect and mechanism of the petroleum ether fraction (LP) and aqueous fraction (LW) of ethanol extract of longan pulp on improving the learning and memory of SAMP8 mice were investigated. SAMP8 mice were used as a mouse model of Alzheimer's disease, and the Morris water maze test was used to evaluate their learning and memory. Nitric oxide (NO), malondialdehyde (MDA), and reduced glutathione (GSH) levels, superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px) activities in the serum, and the protein expression levels of amyloid-beta (Aβ1-42), amyloid precursor protein (APP), and beta-site APP cleaving enzyme 1 (BACE1) in the brains of mice were measured. The results showed that, compared to the model group, LP and LW could significantly ameliorate the learning and memory deficits in Alzheimer’s model mice, decrease the serum NO and MDA content and the protein expression levels of Aβ1-42, APP, and BACE1 in the brain to various degrees, and enhance the activities of SOD and GSH-Px in the serum. These results indicate that both LP and LW of ethanol extract of longan pulp could ameliorate the learning and memory deficits in SAMP8 mice, through a combination of improved antioxidant activity and inhibition of the expression of Aβ and its relevant proteins in the brain, exhibiting the potential to prevent Alzheimer's disease.

国家自然科学青年基金项目（31301459）；国家重点研发计划（2016YFD0400702-2）；广东省自然科学基金项目（2014A030313568）；广东省省级科技计划项目（2016B070701012）；广州市珠江科技新星专项项目（201506010028）；广州市科技计划项目（201704020039）