黄连解毒汤的抗氧化作用及抑制乙酰胆碱酯酶活性的研究

目的:筛选黄连解毒汤中与治疗老年性疾病有关的有效成分。方法:运用紫外分光光度法,建立体外抗氧化模型和抑制乙酰胆碱酯酶(AchE)活性实验模型,分析比较了黄连解毒汤全方、单味药及其主要成分的抗氧化作用和对乙酰胆碱酯酶的抑制作用。结果:复方黄连解毒汤的抗氧化活性比黄连、黄柏和栀子单味药强;黄芩及其主要成分黄芩苷(IC50=12.06μg·mL-1)具有较强的抗氧化活性;与对照品毒扁豆碱和加兰他敏比较,小檗碱(IC50=9.52μg·mL-1)对乙酰胆碱酯酶的抑制活性较高,其次是黄连(IC50=18.89μg·mL-1)水提物,而黄芩和栀子抑制活性不明显。结论:黄连解毒汤具有抗氧化和抑制乙酰胆碱酯酶活性作用,其中具有多羟基的黄酮类是抗氧化活性的主要成分;而生物碱类则是抑制乙酰胆碱酯酶的主要成分。     

藏药中乙酰胆碱酯酶抑制剂的筛选

目的：从8种藏药中筛选对乙酰胆碱酯酶具有高抑制活性的提取物。方法：药材经乙醇提取、酸碱处理、氯仿和正丁醇萃取后,得到氯仿组份和正丁醇组份。各组份用薄层色谱生物自显影法初步筛选其乙酰胆碱酯酶抑制活性,再用改良的Ellman法进一步测定抑制率及半数抑制浓度（IC50）。结果：8种藏药生物碱提取物的氯仿组份有不同程度的乙酰胆碱酯酶抑制活性, 其中止泻木（Holarrhena antidysenterica）、秦艽花（Gentiana straminea）、山莨菪（Anisodus tanguticus）抑制活性最强,IC50分别为6.32 μg.mL-1,28.20 μg.mL-1,34.80 μg.mL-1。正丁醇组份中,山莨菪的抑制活性显著, IC50为51.70 μg.mL-1。结论：止泻木、秦艽花、山莨菪具有显著的乙酰胆碱酯酶抑制活性,说明其含有抑制乙酰胆碱酯酶的成分,为进一步跟踪分离活性成分奠定基础。     

锦鸡儿属和杜鹃属植物抗乙酰胆碱酯酶活性研究

目的:从产自甘肃的锦鸡儿属和杜鹃属植物中筛选出对乙酰胆碱酯酶具有高抑制活性的植物提取物。方法:锦鸡儿属植物经乙醇提取,碱酸处理,乙酸乙酯萃取后,得到多酚提取物。杜鹃属植物经乙醇提取,硅胶柱层析进行粗分后,得到粗分离组分。总多酚组分和粗分离组分采用薄层色谱生物自显影法初步筛选其乙酰胆碱酯酶抑制活性,再用改良的Ellman法进一步测定其对乙酰胆碱酯酶的抑制率。结果:锦鸡儿属中柠条锦鸡儿(Caragana korshinskii)的抑制活性最强,在终浓度为100μg.mL-1时,抑制率超过50%。杜鹃属中,头花杜鹃(Rhododendron capitatum),千里香杜鹃(Rhododendron thymifolium),烈香杜鹃(Rhododendron anthopogonoides)的抑制活性最强,它们的粗分离组分在终浓度为100μg.mL-1时,抑制率大于60%。结论:柠条锦鸡儿(Caragana korshinskii),头花杜鹃(Rhododendron capitatum),千里香杜鹃(Rhododendron thymifolium),烈香杜鹃(Rhododendron anthopogonoides)提取物的抑制活性最强,说明其含有抑制乙酰胆碱酯酶的成分,为进一步跟踪分离得到活性化合物奠定基础。     

中药提取物乙酰胆碱酯酶抑制活性的研究

目的研究中药水提物对乙酰胆碱酯酶的抑制活性。方法选取24味中药做研究对象。应用传统的水提的方法制备中药提取物。使用改进了的Elman比色法检测24种中药的水提物对兔大脑乙酰胆碱酯酶抑制活性。结果黄柏的水提物有显著的乙酰胆碱酯酶抑制活性,在50μg/ml浓度下抑制率达75.58%,IC50值为20.03μg/ml。厚朴的水提取物在50μg/ml浓度下抑制率为43.95%,其IC50值为127.17μg/ml。益智仁的水提物有较弱的乙酰胆碱酯酶抑制活性。结论黄柏等中药提取物对乙酰胆碱酯酶具有很好的抑制活性。     

藏药中乙酰胆碱酯酶抑制剂的筛选

目的:从8种藏药中筛选对乙酰胆碱酯酶具有高抑制活性的提取物。方法:药材经乙醇提取、酸碱处理、氯仿和正丁醇萃取后,得到氯仿部分和正丁醇部分。各部分用薄层色谱生物自显影法初步筛选其乙酰胆碱酯酶抑制活性,再用改良的Ellman法进一步测定抑制率及半数抑制浓度(IC50)。结果:8种藏药生物碱提取物的氯仿部分有不同程度的乙酰胆碱酯酶抑制活性,其中止泻木Holarrhena antidysenterica、秦艽花Gentiana straminea、山莨菪Anisodus tanguticus抑制活性最强,IC50分别为6.32,28.20,34.80 mg·L-1。正丁醇部分中,山莨菪的抑制活性显著,IC50为51.70 mg·L-1。结论:止泻木、秦艽花、山莨菪具有显著的乙酰胆碱酯酶抑制活性,说明其含有抑制乙酰胆碱酯酶的成分,为进一步跟踪分离活性成分奠定基础。     

山莨菪中乙酰胆碱酯酶抑制剂的分离

目的:从山莨菪根部的总生物碱提取物中分离乙酰胆碱酯酶抑制剂。方法:山莨菪根经95%乙醇提取、4mol/L HCl和4mol/L NaOH酸碱处理,氯仿萃取,得到总生物碱。采用薄层色谱生物自显影法跟踪分离目标组分,再用改良的Ellman法进一步测定抑制率。利用多种柱色谱分离得到3个化合物(1-3),通过1H-NMR、13C-NMR、ESI-MS波谱方法并与文献比对鉴定化合物的结构。结果:从山莨菪根部的总生物碱提取物中分离得到3个已知化合物,它们分别被鉴定为东莨菪碱,樟柳碱,阿托品,其乙酰胆碱酯酶抑制率分别为45.28%,38.08%和25.10%。结论:莨菪碱衍生物具有较弱的乙酰胆碱酯酶抑制活性。     

来源于天然产物的生物碱类乙酰胆碱酯酶抑制剂研究进展

乙酰胆碱酯酶抑制剂是阿尔茨海默病治疗药物的研究热点,按来源可分为化学合成和天然产物两大类。生物碱为天然乙酰胆碱酯酶抑制剂的重要来源。通过文献回顾,从结构类型、作用机制及其构效关系等方面综述了植物来源具有乙酰胆碱酯酶抑制活性的生物碱的研究进展,以期为天然生物碱来源的乙酰胆碱酯酶抑制剂的研发提供参考和借鉴。     

杜仲叶绿原酸提取物对脂代谢关键酶活性的影响

目的研究杜仲叶绿原酸提取物对脂代谢关键酶的影响,探讨其降血脂作用机理。方法测定杜仲叶绿原酸提取物对离体胆固醇微胶粒形成,猪肝HMG-CoA还原酶活性以及胰脂肪酶活性的影响。结果杜仲叶绿原酸提取物抑制离体胆固醇微胶粒形成作用(IC50=64.8μg.mL-)1强于绿原酸(IC50=82.2μg.mL-)1;抑制HMG-CoA还原酶效价强于辛伐他汀;抑制胰脂肪酶活性(IC50=2.6μg.mL-)1强于绿原酸(IC50=4.0μg.mL-1)但略低于奥利司他(IC50=1.7μg.mL-)1。结论杜仲叶绿原酸提取物降血脂机理可能与抑制脂质的吸收转化、抑制肠道胆固醇的吸收和减少肝脏胆固醇的合成有关。     

一类新型小檗碱衍生物的合成与生理活性

目的:以具有多种生理活性的小檗碱为原料合成新型衍生物,并研究其细胞增殖抑制作用,抑制乙酰胆碱酯酶和丁酰胆碱酯酶的活性。方法:运用药效团整合策略将具有多种生理活性的小檗碱与抑制组蛋白去乙酰化酶的药效团异羟肟酸、邻苯二胺、巯基进行拼合,通过有机合成手段得到了7个文献未见报道的小檗碱新型衍生物,通过核磁共振氢谱(~1H-NMR),碳谱(~(13)C-NMR)和质谱(MS)进行结构表征,并采用噻唑蓝(MTT)比色法检测了7种小檗碱衍生物对人结肠癌细胞(HCT116),人肝癌细胞(Hep G2),人宫颈癌细胞(He La),人急性淋巴白血病细胞(CCRF-CEM)的增殖活性,采用Ellman法对乙酰胆碱酯酶(ACh E)和丁酰胆碱酯酶(Bu Ch E)抑制活性进行了测试。结果:含甲基酮的小檗碱衍生物同时具有较好细胞增殖抑制作用,抑制乙酰胆碱酯酶的活性,化合物5b对CCRF-CEM细胞株的版抑制浓度(IC_(50))达到了1.48μmol·L~(-1),对乙酰胆碱酯酶的抑制活性IC_(50)为(0.38±0.004)μmol·L~(-1),明显高于先导化合物小檗碱。结论:目标化合物的合成路线为此类生物碱衍生物的合成与活性研究提供了参考,其中化合物5b细胞增殖抑制作用和乙酰胆碱酯酶抑制活性较强,后续值得进一步研究。     

药用植物内生真菌的分离及其次生代谢产物抗乙酰胆碱酯酶活性研究

目的:从4种植物的内生真菌中筛选对乙酰胆碱酯酶具有抑制活性的提取物。方法:用组织块法分离4种植物中的内生真菌;对分离出的纯内生菌用液体培养基发酵培养,用等体积乙酸乙酯和水饱和正丁醇萃取发酵液并用乙醇对菌丝体进行索氏提取,得到各组分提取物;用改良的Ellman法测定提取物的乙酰胆碱酯酶抑制活性。结果:共分离出53株内生真菌,其中有7种内生真菌萃取物有不同程度的抑制乙酰胆碱酯酶活性,其中以XX-10的正丁醇组份的抑酶活性最强。结论:药用植物中存在丰富的内生真菌,其代谢产物具有一定的抗乙酰胆碱酯酶活性,可作为筛选乙酰胆碱酯酶抑制剂的新资源。     

In vitro acetylcholinesterase inhibitory properties of thymol, carvacrol and their derivatives thymoquinone and thymohydroquinone

The aim of this study was to examine in vitro the inhibitory activity exerted by the main constituents of essential oil obtained from the aromatic plant Thymus vulgaris L. on acetylcholinesterase (AChE). The total essential oil and selected compounds, specifically linalool and thymol, carvacrol and their derivatives thymoquinone and thymohydroquinone, were tested for AChE inhibition. Thymohydroquinone exhibited the strongest AChE inhibitory effect over the range of concentrations. The AChE inhibitory potential decreased in the following order: thymohydroquinone > carvacrol > thymoquinone > essential oil > thymol > linalool. It is interesting that the AChE inhibitory effect exerted by carvacrol was 10 times stronger than that exerted by its isomer thymol, although thymol and carvacrol have a very similar structure.     

Screening of Indian medicinal plants for acetylcholinesterase inhibitory activity

The cholinergic hypothesis of Alzheimer's disease (AD) has provided the rationale for the current pharmaco-therapy of this disease, in an attempt to reduce the cognitive decline caused by cholinergic deficits. Nevertheless, the search for potent and long-acting acetylcholinesterase (AChE) inhibitors that exert minimal side effects in AD patients is still ongoing. AChE inhibitors are currently the only approved therapy for the treatment of Alzheimer's disease; only a limited number of drugs are commercially available. Hydroalcohol extracts of six herbs, Andrographis paniculata, Centella asiatica, Evalvulus alsinoides, Nardostachys jatamansi, Nelumbo nucifera, Myristica fragrans used in Indian systems of medicine, were tested for in vitro acetylcholinesterase inhibitory activity based on Ellman's method in 96-well microplates using AChE obtained from bovine erythrocytes. The results showed that the hydroalcohol extract from Centella asiatica, Nardostachys jatamansi, Myristica fragrans, Evalvulus alsinoides inhibited 50% of AChE activity at concentrations of 100-150 microg/mL. Andrographis paniculata and Nelumbo nucifera extracts showed a weak inhibition of acetylcholinesterase with IC(50) values of 222.41 +/- 19.87 microg/mL and 185.55 +/- 21.24 microg/mL, respectively. Physostigmine was used as a standard and showed inhibition of acetylcholinesterase with an IC(50) value of 0.076 +/- 0.0042 microg/mL.     

Screening of selected Indian medicinal plants for acetylcholinesterase inhibitory activity

Seventy-six plant extracts including methanolic and successive water extracts from 37 Indian medicinal plants were investigated for acetylcholinesterase (AChE) inhibitory activity (in vitro). Results indicated that methanolic extracts to be more active than water extracts. The potent AChE inhibiting methanolic plant extracts included Withania somnifera (root), Semecarpus anacardium (stem bark), Embelia ribes (Root), Tinospora cordifolia (stem), Ficus religiosa (stem bark) and Nardostachys jatamansi (rhizome). The IC(50) values obtained for these extracts were 33.38, 16.74, 23.04, 38.36, 73.69 and 47.21mug/ml, respectively. These results partly substantiate the traditional use of these herbs for improvement of cognition.     

药用植物内生真菌的分离及其次生代谢产物的生物活性研究

目的：从4种植物的内生真菌中筛选对单胺氧化酶及乙酰胆碱酯酶具有抑制活性的提取物。方法：用组织块法分离4种植物中的内生真茵;对分离出的纯内生真菌用液体培养基发酵培养,用等体积乙酸乙酯萃取发酵液并用乙醇对茵丝体进行回流提取,得到各组分提取物;用酶标法测定提取物的单胺氧化酶及乙酰胆碱酯酶抑制活性。结果：共分离出36株内生真菌,其中有16种内生真菌提取物有不同程度的抑制单胺氧化酶活性,其中GT-7茵液萃取物抑酶活性最强。2种内生真菌提取物有乙酰胆碱酯酶抑制活性。结论：药用植物中存在丰富的内生真菌,其代谢产物具有一定的单胺氧化酶及乙酰胆碱酯酶抑制活性,可作为筛选单胺氧化酶及乙酰胆碱酯酶抑制剂的新资源。     

The in vitro screening for acetylcholinesterase inhibition and antioxidant activity of medicinal plants from Portugal

Essential oil, ethanolic extract and decoction of 10 plant species from interior Portugal were analyzed for their activity towards acetylcholinesterase (AChE) enzyme and their antioxidant activity. Of these, Melissa officinalis, Paronychia argentea, Sanguisorba minor, Hypericum undulatum and Malva silvestris are used in herbal medicine, Laurus nobilis and Mentha suaveolens as condiments, and Salvia officinalis, Lavandula angustifolia and Lavandula pedunculata also as aromatics. Melissa officinalis and Mentha suaveolens showed AChE inhibitory capacity higher then 50% in the essential oil fraction. Laurus nobilis, Hypericum undulatum, and Sanguisorba minor showed a high inhibition value of AChE in the ethanolic fraction, 64% (1 mg ml(-1)) 68% (0.5 mg ml(-1)), and 78% (1 mg ml(-1)), respectively. Higher values of AChE inhibitory activity were found using decoctions of Lavandula pedunculata, Mentha suaveolens and Hypericum undulatum, 68, 69 and 82% (at a concentration of 5mg dry plant ml(-1) of assay), respectively. The free radical scavenger activity was higher for the polar extracts. In the water extracts most of the plants showed values around 90%. When antioxidant activity was measured with the beta-carotene-linoleic acid assay high activity (65-95%) was also found in the water extracts. Hypericum undulatum, Melissa officinalis and Laurus nobilis showed both high AChE inhibitory capacity and antioxidant activity.     

中国南海海岸红树真菌Xylaria sp.代谢产物在体外对乙酰胆碱酯酶活性的影响

目的:体外研究中国南海海岸红树林真菌Xylaria sp.代谢产物Xyloketal A～D对乙酰胆碱酯酶(AChE)活性的影响.方法:采用改良Ellmen法测定AChE活性,考察受试化合物在体外对AChE活性及其酶动力学特征的影响,并就这些化合物对AChE和丁酰胆碱酯酶(BuChE)的选择性进行比较.结果:xyloketal A～D在体外对AChE活性均有不同程度的抑制作用,并呈一定剂量依赖关系,IC50值分别为29.9、137.4、109.3和425.6 μmol/L.通过对AChE酶抑制动力学曲线进行分析发现,xyloketals对AChE的抑制表现为可逆非竞争性抑制.此外,对于另一种胆碱酯酶BuChE,阳性药维那克林及xyloketals均表现出一定降低作用,但相对而言xyloketals对AChE的选择性较强.结论:xlylketals在体外对AChE活性有可逆非竞争性抑制作用,表明该类化合物可能作为抗早老性痴呆(AD)药物进行开发,同时该结果亦提示,从海洋微生物代谢产物中寻找新型AChE抑制剂可能成为开发AD治疗药物中的新战略.     

Screening of medicinal plants from Iranian traditional medicine for acetylcholinesterase inhibition

To find new herbal compounds with an acetylcholinesterase (AChE) inhibitory effect, this study focused on herbal drugs and resins which have been used in Iranian traditional medicine for the treatment of cognitive disorders. Forty drugs were selected from authoritative written documents of Iranian traditional medicine. Each drug was extracted by accelerated solvent extraction using dichloromethane followed by methanol. The 80 extracts were screened for AChE inhibitory activity by a TLC bioautography method. The inhibiting effect of the 32 most active extracts was measured by a microplate colorimetric assay. Due to the best activity, the seeds of Peganum harmala L. were investigated in detail. From the TLC bioautography assay the alkaloids harmaline and harmine were identified as active compounds. This result was confirmed by means of HPLC‐DAD. The IC₅₀ values were 41.2 μg/mL for the methanol extract, 95.5 μg/mL for the dichloromethane extract, 8.4 μg/mL for harmaline and 10.9 μg/mL for harmine. The concentrations of active compounds in the extracts were determined by a fast and precise HPLC method. As the amounts of harmaline and harmine in the extracts were correlated with the IC₅₀ values of the extracts, it can be concluded that these two alkaloids are responsible for the AChE inhibitory activity of P. harmala. Copyright © 2011 John Wiley & Sons, Ltd.     

Isolation of narciprimine from Cyrtanthus contractus (Amaryllidaceae) and evaluation of its acetylcholinesterase inhibitory activity

Ethnopharmacological relevance

Plants of the family Amaryllidaceae are used widely in traditional medicine in South Africa. Several of these, including representatives of the genus Cyrtanthus find use in the treatment of mental illness and age-related dementia.

Aim of the study

Based on the distribution of central nervous system-activating alkaloidal constituents within the genus Cyrtanthus, Cyrtanthus contractus was here explored for such compounds which could interact with acetylcholinesterase (AChE), of significance in the progression of neurodegeneration associated with Alzheimer's disease.

Materials and methods

The known phenanthridone alkaloid narciprimine was isolated via column chromatography of the ethanolic extract of bulbs of Cyrtanthus contractus. The structure of the compound was determined by high field 2D NMR and mass spectroscopic techniques. The classical method of Ellman et al. was used in the determination of AChE inhibitory activity.

Results

The isolation of narciprimine from Cyrtanthus contractus is a landmark find since it has previously only been identified in Zephyranthes, Narcissus and Lycoris, genera endemic to the Americas, Europe and Asia, respectively. Narciprimine exhibited micromolar inhibitory activity (IC₅₀ 78.9) against the enzyme acetylcholinesterase.

Conclusion

This work represents the first isolation of narciprimine from an African Amaryllidaceae species, which may be of chemotaxonomic significance. The AChE inhibitory activity of narciprimine, taken together with activities of other structurally similar inhibitors within the series affords further insight to the structural details of the lycorine alkaloid acetylcholinesterase inhibitory pharmacophore.