Uddin Md Nasim, Afrin Rejina, Uddin Md Josim, Uddin Md Jalal, Alam A H M K, Rahman Aziz Abdur, Sadik Golam
Department of Pharmacy, University of Rajshahi, Rajshahi, 6205, Bangladesh.
BMC Complement Altern Med. 2015 Jun 23;15:195. doi: 10.1186/s12906-015-0728-y.
Alzheimer's disease (AD) is a progressively developing neurodegenerative disorder of the brain in the elderly people. Vanda roxburghii Rbr. root has been used traditionally in Bangladesh as tonic to brain and in the treatment of nervous system disorders including AD. Therefore, we aimed to investigate the cholinesterase inhibitory activities and antioxidant properties of the extracts from V. roxburghii.
The crude methanol extract from the roots of plant was sequentially fractionated with petroleum ether, chloroform, ethylacetate and water to yield their corresponding extracts. The extracts were assessed for acetylcholinesterase and butyrylcholinesterase inhibitory activity by modified Ellman method and antioxidant property by several assays including ferric reducing antioxidant power, scavenging of 1,1-diphenyl-2-picrylhydrazyl (DPPH) free radical and hydroxyl radical, and inhibition of lipid peroxidation. Endogenous substances in the extracts were analyzed by the standard phytochemical methods and active compound was isolated by the chromatographic methods.
Chloroform extract was shown to demonstrate strong ferric-reducing antioxidant power and scavenging activity against DPPH and hydroxyl free radicals when compared with the other extracts and the reference standard catechin. The antioxidant effect was further verified by inhibition of lipid peroxidation in rat brain homogenates. Likewise, the chloroform extract exhibited the highest inhibition against both the acetylcholinesterase and butyrylcholinesterase enzymes with IC50 values of 221.13 and 82.51 μg/ml, respectively. Phytochemical screening revealed a large amount of phenolics and flavonoids in the chloroform extract. Bioactivity guided separation techniques led to the isolation of a strong antioxidant from the chloroform extract and its structure was determined as gigantol on the basis of spectral studies.
These results suggest that the chloroform extract of V. roxburghii, possibly due to its phenolic compounds, exert potential antioxidant and cholinesterase inhibitory activities, which may be useful in the treatment of AD.
阿尔茨海默病（AD）是一种在老年人中逐渐发展的脑部神经退行性疾病。在孟加拉国，黑叶万代兰的根传统上被用作补脑剂，并用于治疗包括AD在内的神经系统疾病。因此，我们旨在研究黑叶万代兰提取物的胆碱酯酶抑制活性和抗氧化特性。
将植物根部的粗甲醇提取物依次用石油醚、氯仿、乙酸乙酯和水进行分级分离，得到相应的提取物。采用改良的Ellman法评估提取物对乙酰胆碱酯酶和丁酰胆碱酯酶的抑制活性，并通过多种测定方法评估其抗氧化特性，包括铁还原抗氧化能力、1,1-二苯基-2-苦基肼（DPPH）自由基和羟基自由基清除能力以及脂质过氧化抑制能力。通过标准植物化学方法分析提取物中的内源性物质，并通过色谱方法分离活性化合物。
与其他提取物和参考标准儿茶素相比，氯仿提取物显示出较强的铁还原抗氧化能力以及对DPPH和羟基自由基的清除活性。通过抑制大鼠脑匀浆中的脂质过氧化进一步验证了抗氧化作用。同样，氯仿提取物对乙酰胆碱酯酶和丁酰胆碱酯酶的抑制作用最强，IC50值分别为221.13和82.51μg/ml。植物化学筛选显示氯仿提取物中含有大量酚类和黄酮类化合物。生物活性导向分离技术从氯仿提取物中分离出一种强抗氧化剂，并根据光谱研究确定其结构为巨球兰酚。
这些结果表明，黑叶万代兰的氯仿提取物可能因其酚类化合物而具有潜在的抗氧化和胆碱酯酶抑制活性，这可能对AD的治疗有用。
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