马齿苋乙醇及其正乙醇提取物对D-半乳糖致衰老小鼠的学习记忆作用

目的：研究马齿苋不同提取物对D-半乳糖致衰老小鼠的学习记忆能力及其作用机制。方法：取小鼠随机分为正常组、模型组、马齿苋正丁醇提取物组(0.5、0.25g/(kg ·d)，以体质量计)和马齿苋乙醇提取物组(1、0.5g/(kg ·d)，以体质量计)。除正常组颈背部皮下注射生理盐水外，其他各组均皮下注射D-半乳糖(1g/(kg ·d)，以体质量计)，注射后每天下午灌胃给药，连续42d。采用避暗法和水迷宫法测定衰老小鼠学习记忆能力，同时测定衰老小鼠脑组织丙二醛(MDA)含量、超氧化物歧化酶(SOD)和谷胱甘肽过氧化物酶(GSH-Px)活性。结果：马齿苋正丁醇提取物(0.5、0.25g/(kg ·d))均可提高衰老小鼠学习记忆能力(P＜0.01)，0.5g/(kg ·d)剂量组可显著提高衰老小鼠脑组织SOD和GSH-Px的活性(P＜0.05，P＜0.01)，0.25g/(kg ·d)剂量组马齿苋正丁醇提取物可显著降低MDA含量(P＜0.05)；马齿苋乙醇提取物可极显著提高衰老小鼠学习记忆能力(P＜0.01)，显著降低脑组织MDA含量(P＜0.05)。结论：马齿苋不同提取物能明显改善衰老小鼠学习记忆能力，其机制可能与提高SOD、GSH-Px活性，降低MDA含量有关。马齿苋正丁醇提取物好于马齿苋乙醇提取物。

Effects of Ethanol and n-Butanol-soluble Extract from Herba Portulacae on Learning and Memory Performance in D-Galactose-induced Senile Mice

Objective: To study the effects and mechanisms of ethanol extract and its n-butanol-soluble fraction from Herba Portulacae on learning and memory performance in senile mice induced by D-galactose. Method: Mice were randomly divided into 6 groups: control group, model group and n-butanol-soluble fraction treatment (0.5 g/(kg ·d) and 0.25 g/(kg ·d)) groups and ethanol extract treatment groups (1 g/(kg ·d) and 0.5 g/(kg ·d)) groups. Normal saline was given to control group once daily for 42 consecutive days by subcutaneous injection in the neck back, and 1 g/(kg ·d) D-galactose to the other 5 groups using the same administration route before intragastric administration of the same volume of distilled water and corresponding drugs (in aqueous solution) every afternoon during the administration period. Mouse learning and memory performance were tested by step-through test and water maze test, and MDA content and SOD and GSH-Px activities in the brain of senile mice were assayed. Results: Both dosages of n-butanol-soluble fraction could significantly improve mouse learning and memory performance (P <0.01), and the dosage of 0.5 g/(kg ·d) resulted in a significant increase in the activities of SOD and GSH-Px in the brain (P <0.05, P <0.01), and the other dosage significantly decreased MDA content in the brain (P <0.05). Meanwhile, ethanol extract from Herba Portulacae had a highly significant improving effect on mouse learning and memory performance (P <0.01) and significantly reduced MDA content in the brain (P <0.05). Conclusion: From these results, we concluded that ethanol extract and its n-butanol-soluble fraction from Herba Portulacae are capable of significantly improving senile mouse learning and memory performance. The possible mechanisms may be through increasing SOD and GSH-Px activities and decreasing MDA content in the brain. Furthermore, ethanol extract from Herba Portulacae is superior to its n-butanol-soluble fraction.