Asaduzzaman Md, Uddin Md Josim, Kader M A, Alam A H M K, Rahman Aziz Abdur, Rashid Mamunur, Kato Kiyoko, Tanaka Toshihisa, Takeda Masatoshi, Sadik Golam
Department of Pharmacy, University of Rajshahi, Rajshahi, Bangladesh.
Psychogeriatrics. 2014 Mar;14(1):1-10. doi: 10.1111/psyg.12031.
Alzheimer's disease (AD) is a progressive neurodegenerative disorder clinically characterized by loss of memory and cognition. The effective therapeutic options for AD are limited and thus there is a demand for new drugs. Aegle marmelos (Linn.) (A. marmelos) leaves have been used in traditional medicine to promote intellect and enhance memory. In this study, we evaluated A. marmelos for its acetylcholinesterase (AChE) inhibitory activity and antioxidant property in vitro in the treatment of AD.
A crude methanol extract and four fractions (petroleum ether, chloroform, ethyl acetate and aqueous) were prepared from the leaves of A. marmelos. The preparations were assessed for AChE inhibitory activity by the Ellman method, and their antioxidant properties were assessed by several assays: reducing power, scavenging of 1,1-diphenyl-2-picrylhydrazyl free radical and hydroxyl radical, and inhibition of lipid peroxidation. Qualitative and quantitative analyses of endogenous substances in A. marmelos were performed by the standard phytochemical methods.
Among the different extracts tested, the ethyl acetate fraction exhibited the highest inhibition of AChE activity. In the same way, ethyl acetate fraction showed the highest reducing activity and radical scavenging ability towards the 1,1-diphenyl-2-picrylhydrazyl (half maximal inhibitory concentration = 3.84 μg/mL) and hydroxyl free radicals (half maximal inhibitory concentration = 5.68 μg/mL). The antiradical activity of the ethyl acetate fraction appeared to be similar to that of the reference standard butylated hydroxytoluene and catechin used in this study. In addition, the ethyl acetate fraction displayed higher inhibition of brain lipid peroxidation. Phytochemical screening of different extractives of A. marmelos showed the presence of phenols and flavonoids, alkaloid, saponin, glycoside, tannin and steroids. Quantitative analysis revealed higher contents of phenolics (58.79-mg gallic acid equivalent/g dried extract) and flavonoids (375.73-mg gallic acid equivalent/g dried extract) in the ethyl acetate fraction.
The results suggest that the ethyl acetate fraction of A. marmelos is a significant source of polyphenolic compounds with potential AChE inhibitory property and antioxidant activity and, thus, may be useful in the treatment of AD.
阿尔茨海默病（AD）是一种进行性神经退行性疾病，临床特征为记忆和认知丧失。AD的有效治疗选择有限，因此对新药有需求。印度枳椇（Aegle marmelos (Linn.)）叶在传统医学中用于益智和增强记忆。在本研究中，我们评估了印度枳椇叶在体外治疗AD中的乙酰胆碱酯酶（AChE）抑制活性和抗氧化特性。
从印度枳椇叶中制备了粗甲醇提取物和四个馏分（石油醚、氯仿、乙酸乙酯和水相）。通过Ellman法评估制剂的AChE抑制活性，并通过几种测定法评估其抗氧化特性：还原能力、1,1-二苯基-2-苦基肼自由基和羟基自由基的清除能力以及脂质过氧化抑制。采用标准植物化学方法对印度枳椇中的内源性物质进行定性和定量分析。
在测试的不同提取物中乙酸乙酯馏分对AChE活性的抑制作用最强。同样，乙酸乙酯馏分对1,1-二苯基-2-苦基肼（半数最大抑制浓度 = 3.84 μg/mL）和羟基自由基（半数最大抑制浓度 = 5.68 μg/mL）表现出最高的还原活性和自由基清除能力。乙酸乙酯馏分的抗自由基活性似乎与本研究中使用的参考标准丁基羟基甲苯和儿茶素相似。此外，乙酸乙酯馏分对脑脂质过氧化的抑制作用更强。对印度枳椇不同提取物的植物化学筛选显示存在酚类、黄酮类、生物碱、皂苷、糖苷、单宁和甾体。定量分析表明乙酸乙酯馏分中酚类（58.79 mg没食子酸当量/g干提取物）和黄酮类（375.73 mg没食子酸当量/g干提取物）含量较高。
结果表明，印度枳椇的乙酸乙酯馏分是具有潜在AChE抑制特性和抗氧化活性的多酚类化合物的重要来源，因此可能对AD治疗有用。
