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排序方式: 共有265条查询结果,搜索用时 15 毫秒
1.
目的探讨秦皮化学成分的研究进展,为进一步有效开发利用秦皮及其药理学、药代动力学等临床应用提供参考。方法对国内外发表有关秦皮中化学成分的文献进行综述。结果秦皮中含有香豆素、环烯醚萜、木质素、酚类、三萜类等多种具有生物活性的化学成分。结论秦皮中有效成分的分离及纯化、检测方法、药理学和药代动力学等临床应用还有待做进一步的研究和探讨。  相似文献   
2.
Context: Triterpenes from Poria cocos Wolf (Polyporaceae) have been used to treat various diseases in traditional Chinese medicine. However, the antiepileptic effects and mechanism are not fully understood.

Objective: The objective of this study is to investigate the antiepileptic properties of total triterpenes (TTP) from the whole P. cocos.

Materials and methods: The ethanol extract TTP was identified by HPLC fingerprint analysis. Male ICR mice were gavaged (i.g.) with TTP (5, 20, 80 or 160?mg/kg) or reference drugs twice a day for 7 d. Antiepileptic activities of TTP were evaluated by maximal electroshock (MES)- and pentylenetetrazole (PTZ)-induced seizures in mice for 30 and 60?min, respectively. Locomotor activity and Rota-rod tests were performed for 60?min and 5?min, respectively. The levels of glutamic acid (Glu), aspartic acid (Asp), γ-aminobutyric acid (GABA) and glycine (Gly) in convulsive mice were estimated. The chronic epileptic model of Wistar rats was built to measure expressions of glutamate decarboxylase 65 (GAD65) and GABAA in rat brain after TTP treatment.

Results: The LC50 of TTP (i.g.) was above 6?g/kg. TTP (5–160?mg/kg) protected mice against MES- and PTZ-induced convulsions at 65.0% and 62.5%, respectively, but have no effect on rota-rod treadmill; TTP (20–160?mg/kg) significantly reduced the locomotor activities, shortened the onset of pentobarbital sodium-induced sleep; TTP decreased Glu and Asp levels in convulsive mice, but increased the GAD65 and GABAA expressions in chronic epileptic rats at doses usage.

Discussion and conclusion: TTP extracted from P. cocos possessed potential antiepileptic properties and is a candidate for further antiepileptic drug development.  相似文献   
3.
Asiatic acid is a major pentacyclic triterpene isolated from Centella asiatica. It shows a variety of bioactivities. In order to obtain its derivatives, potentially useful for detailed pharmacological studies, the substrate was subjected to incubations with selected micro-organisms. In this work, asiatic acid was converted into three new compounds: 2α,3β,23,30-tetrahydroxyurs-12-ene-28-oic acid (1), 2α,3β,22β,23-tetrahydroxyurs-12-ene-28-oic acid (2), and 2α,3β,22β,23,30-pentahydroxyurs-12-ene-28-oic acid (3) by the fungus Alternaria longipes AS 3.2875. The structures of the three metabolites were determined by 1D and 2D NMR spectral data.  相似文献   
4.
Two new triterpene saponins, mandshunosides A and B (1 and 2), were isolated from the roots and rhizomes of Clematis mandshurica. Their structures were elucidated on the basis of spectroscopic evidence and hydrolysis products. Compounds 1 and 2 showed inhibitory activities against two colorectal human cancer cells HCT 116 (IC50 2.1 μM for 1 and 2.5 μM for 2) and HT-29 (IC50 3.7 μM for 1 and 3.3 μM for 2).  相似文献   
5.
Three new oleanane-type triterpene saponins, namely licorice-saponin M3 (1), licorice-saponin N4 (2), and licorice-saponin O4 (3), an artificial product (4), as well as five known triterpene glucuronides (59), were isolated from the roots of Glycyrrhiza glabra L. Their structures were established using 1D and 2D NMR spectroscopy, mass spectrometry, and by comparison with spectroscopic data reported in the literature. The inhibitory effects of the selected compounds on neuraminidase were evaluated, and the preliminary structure–activity relationship was also predicted.  相似文献   
6.
Abstract

4-Hydroxy-4, 7-dimethyl-α.-tetralone (1), 4,5-dihydroblumenol A (2), N.-trans.-feruloyltyramine (3), and 24–methylenelanosta-7, 9(11)-dien-3-β., 15α.-diol (4) were isolated from the stem bark of Polyalthia jucunda. (Piere) Finet & Gagnep (Annonaceae). All the compounds were evaluated for their effects on growth of four human tumor cell lines [ER(+) MCF-7, ER(?) MDA-MB-23, SF 268, and NCI-H460] and of a non–tumor cell line (MRC-5). Only compound 4 exhibited a dose-dependent growth inhibitory effect against both tumor and non–tumor cell lines but with less effect on the latter. Using the TUNEL assay, it was found that the inhibitory effect of compound 4 on NCI-H460 cells was probably caused by apoptosis.  相似文献   
7.
The recent American approval of Cancidas?, a semi-synthetic echinocandin, for salvage treatment of aspergillosis has demonstrated that the cell wall is a clinically viable target for treating fungal infections. Recently, a variety of new, sulfated members of the echinocandin lipopeptide family have been reported, which, like other echinocandins, are glucan synthesis inhibitors. In addition, two new classes of lipopeptide glucan synthesis inhibitors, the aerothricin lipopeptidolactones and the Sankyo lipopeptides, have been identified, as well as a novel member of the papulacandin family of liposaccharide glucan synthesis inhibitors. The first new structural class of glucan synthesis inhibitors discovered in over 20 years, the so-called sterol glycosides, is reviewed. Five different structural types within this class have been characterised. Finally, several novel compounds with cell wall antifungal activity based on inhibition of chitin synthase are reviewed.  相似文献   
8.
目的对中国南海海域细薄星芒海绵的三萜成分进行研究。方法采用硅胶柱色谱、Sephadex LH-20凝胶色谱、ODS C18柱色谱、半制备型HPLC等方法进行分离,根据理化性质和波谱分析鉴定化合物的结构。结果分离并鉴定了5个异玛拉巴烷型三萜化合物,分别为stelletinA(Ⅰ),stelletin B(Ⅱ),22,23-dihydrostelletin D(Ⅲ),jaspolide B(Ⅳ)和jaspolide A(Ⅴ)。结论化合物Ⅲ~Ⅴ首次从该种海绵中获得。  相似文献   
9.
[目的]考察桦褐孔菌中三萜化合物发生酰化成酯后对其抗肿瘤活性的影响。[方法]采用溶剂提取法及硅胶柱层析、ODS开放柱层析和制备型高效液相色谱(HPLC)等从桦褐孔菌子实体中分离制备其代表性羊毛脂烷型三萜,并以此为原料,采用琥珀酸酐进行酰化反应,进而采用噻唑蓝(MTT)法测试原料化合物及其酰化产物对A549、Hela、MCF-7及4T1肿瘤细胞的抑制活性。[结果]从桦褐孔菌中分离并鉴定了化合物inotodiol(1)、trametenolic acid(2)及inonotusane A(3),将他们进行酰化后分别得到inotodiol-3-琥珀酸单酯(1a)、inotodiol-22-琥珀酸单酯(1b)、inotodiol-3,22-琥珀酸二酯(1c)、trametenolic acid-3-琥珀酸单酯(2a)和inonotusane A-3-琥珀酸单酯(3a)。MTT结果表明,化合物1的3-位、22-位酰化后(1a, 1b, 1c)对A549和4T1肿瘤细胞的抑制活性均增强,此外,而其3-位酰化后(1a)还大大增强了对MCF-7肿瘤细胞的抑制活性。化合物2酰化后对活性无影响。化合物3的3-位酰化后对A549、MCF-7及4T1细胞的抑制活性均明显增强,其中对A549表现出最强的抗肿瘤活性(IC50=9.53μmol/L)。[结论]化合物inotodiol(1)的3-位、22-位和inonotusane A(3)的3-位酰化后均增强了其肿瘤活性,为其进一步的结构修饰提供了有价值的参考。  相似文献   
10.
The differences between the biosynthesis of sterols in higher plants and yeast/mammals are believed to originate at the cyclization step of oxidosqualene, which is cyclized to cycloartenol in higher plants and lanosterol in yeast/mammals. Recently, lanosterol synthase genes were identified from dicotyledonous plant species including Arabidopsis, suggesting that higher plants possess dual biosynthetic pathways to phytosterols via lanosterol, and through cycloartenol. To identify the biosynthetic pathway to phytosterol via lanosterol, and to reveal the contributions to phytosterol biosynthesis via each cycloartenol and lanosterol, we performed feeding experiments by using [6-13C2H3]mevalonate with Arabidopsis seedlings. Applying 13C-{1H}{2H} nuclear magnetic resonance (NMR) techniques, the elucidation of deuterium on C-19 behavior of phytosterol provided evidence that small amounts of phytosterol were biosynthesized via lanosterol. The levels of phytosterol increased on overexpression of LAS1, and phytosterols derived from lanosterol were not observed in a LAS1-knockout plant. This is direct evidence to indicate that the biosynthetic pathway for phytosterol via lanosterol exists in plant cells. We designate the biosynthetic pathway to phytosterols via lanosterol “the lanosterol pathway.” LAS1 expression is reported to be induced by the application of jasmonate and is thought to have evolved from an ancestral cycloartenol synthase to a triterpenoid synthase, such as β-amyrin synthase and lupeol synthase. Considering this background, the lanosterol pathway may contribute to the biosynthesis of not only phytosterols, but also steroids as secondary metabolites.  相似文献   
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