Glycation inhibitory activity and the identification of an active compound in Plantago asiatica extract

The glycation reaction involves a series of non-enzymatic reactions between the carbonyl group on reducing sugars and the amino group on proteins leading to the formation of advanced glycation end-products (AGEs), which are acknowledged to be involved in the pathogenesis of diabetic and aging-related complications. Consequently, the development of AGE inhibitors is considered to have therapeutic potential in patients with diabetes or age-related diseases. The preliminary results showed that a methanol extract (PAE) of Plantago asiatica, which is traditionally used as a folk medicine in Asian countries to treat fever, cough, wound etc., had strong glycation inhibitory activity. The effects of the extract on AGE fluorescence were dose-dependent, reaching 41% inhibition at 0.1 microg/mL of extract. The purified principle from PAE was identified as plantamajoside. As well as antioxidant activities, in vitro glycation inhibitory activities with 10 and 25 mm plantamajoside were higher than those with 10 and 25 mm aminoguanidine. The results demonstrate that PAE and plantamajoside had significant effects on in vitro AGE formation, and the glycation inhibitory activity and antioxidant activity of plantamajoside were comparable to those obtained using millimolar concentrations of the standard antiglycation agent aminoguanidine, and the antioxidant ascorbate, respectively.     

Anti-angiogenic and inhibitory activity on inducible nitric oxide production of the mushroom Ganoderma lucidum

Fresh fruit bodies of Ganoderma lucidum were extracted with 70% ethanol at room temperature. The extract (GL) showed significant anti-angiogenic activity, which was detected using a chick embryo chorioallantoic membrane assay. GL significantly inhibited LPS-induced NO production in RAW 264.7 macrophages. These results support the anti-tumor effect of Ganoderma lucidum.     

Neoflavonoids and related constituents from Nepalese propolis and their nitric oxide production inhibitory activity

A methanolic extract of Nepalese propolis yielded 10 new open-chain neoflavonoids (1-10), a new chalcone (11), and eight previously reported compounds (12-19). Their structures were determined on the basis of spectroscopic data and chemical conversion. The isolated compounds other than 5, 8, and 16 showed dose-dependent inhibitory activities on nitric oxide production in lipopolysaccharide-activated macrophage-like J774.1 cells and were more active than a positive control, N(G)-monomethyl-L-arginine (IC(50), 27.1 microM). The most potent activities, of 6 and 7 (IC(50), 0.5 microM), were greater than another positive control, caffeic acid phenethyl ester (IC(50), 4.8 microM).     

Prenylated flavonoids from the heartwood of Artocarpus communis with inhibitory activity on lipopolysaccharide-induced nitric oxide production

A new prenylated chalcone, 3' ',3' '-dimethylpyrano[3',4']2,4,2'-trihydroxychalcone (1), was isolated from the heartwood of Artocarpus communis. Two flavonoid derivatives, (-)-cycloartocarpin (9) and (-)-cudraflavone A (10), were isolated as new isomers. In addition, eight known flavonoids, isobacachalcone (2), morachalcone A (3), gemichalcones B (4) and C (5), artocarpin (6), cudraflavone C (7), licoflavone C (8), and (2S)-euchrenone a(7) (11), were isolated and identified from this plant for the first time. Compounds 1-4, 6, and 11 exhibited potent inhibitory activity on nitric oxide production in RAW264.7 LPS-activated mouse macrophage cells with IC(50) values of 18.8, 6.4, 16.4, 9.3, 18.7, and 12.3 microM, respectively. The structure of compound 1 was elucidated by spectroscopic data analysis, including 1D and 2D NMR experiments.     

Screening of selected plant extracts for in vitro inhibitory activity on human immunodeficiency virus

As part of our screening of anti-AIDS agents from natural sources, extracts of 15 medicinal plants widely used in the folk medicines of North America and Europe were evaluated in vitro. Most of the extracts tested were relatively nontoxic to human lymphocytic MT-2 cells, but only the extracts of Hysopp officinalis and Dittrichia viscosa exhibited anti-HIV activity in an in vitro MTT assay. The 50% hydroalcohol extract of Hysopp officinalis and the aqueous extract of Dittrichia viscosa showed inhibitory effects against HIV-1 induced infections in MT-2 cells at concentrations ranging from 50 to 100 microg/mL and 25 to 400 microg/mL, respectively. Both extracts showed no appreciable cytotoxicity at these concentrations.     

Saponins from Cussonia bancoensis and their inhibitory effects on nitric oxide production

Two new triterpenoid saponins (1 and 2) were isolated from the stem bark of Cussonia bancoensis together with the known stigmasterol, ursolic acid, 23-hydroxyursolic acid (3), and 3beta-hydroxylup-20(29)-en-28-oic acid. On the basis of their spectroscopic data and on chemical transformations, the structures of the new saponins have been established as 3-O-(alpha-Ll-arabinopyranosyl)-23-hydroxyursolic acid (1) and 3-O-(beta-D-glucopyranosyl)-23-hydroxyursolic acid (2). In a nitric oxide (NO)-production bioassay, compound 3 exhibited significant NO inhibitory activity, while compounds 1 and 2 were less potent than 3.     

Anti-inflammatory activity of herbal medicines: inhibition of nitric oxide production and tumor necrosis factor-alpha secretion in an activated macrophage-like cell line

Houttuynia cordata Thunb. (HC), Glycyrrhiza uralensis Fischer (GU), Forsythia suspense (Thunb.) Vahl (FS), and Lonicera japonica Thunb. (LJ) are Chinese herbs known to possess anti-inflammatory properties. The effects of aqueous extracts of these herbs on the production of the pro-inflammatory mediators, nitric oxide (NO) and tumor necrosis factor-alpha (TNF-alpha) were examined in an activated macrophage-like cell line, RAW 264.7 cells. Aqueous extracts from FS at 0.0625-2.0 mg/ml inhibited in vitro production of NO and secretion of TNF-alpha in a dose-dependent manner. FS at 1.0-2.0 mg/ml and 0.125-2.0 mg/ml significantly inhibited NO production and TNF-alpha, respectively. An extract of LJ demonstrated potent inhibition of both NO production and TNF-alpha secretion in a dose-dependent manner. An aqueous extract from HC inhibited NO production in a dose-dependent manner, but minimally (approximately 30%) inhibited TNF-a secretion at 0.0625 and 0.125 mg/ml. In contrast, an aqueous extract of GU had a minimal effect on both the production of NO and the secretion of TNF-alpha. Viability of cells at all concentrations studied was unaffected as determined by MTT cytotoxicity assay and trypan blue dye exclusion. These results suggest that aqueous extracts from FS, LJ and HC have anti-inflammatory actions as measured by inhibition of NO production and/or TNF-alpha secretion.     

Inhibitory activity of plant extracts on nitric oxide synthesis in LPS-activated macrophages

Nitric oxide (NO) produced in large amounts by inducible nitric oxide synthase (iNOS) is known to be responsible for the vasodilation and hypotension observed in septic shock and inflammation. Inhibitors of iNOS, thus, may be useful candidates for the treatment of inflammatory diseases accompanied by overproduction of NO. We prepared alcoholic extracts of woody plants and screened the inhibitory activity of NO production in lipopolysaccharide (LPS)-activated macrophages after the treatment of these extracts. Among 83 kinds of plant extracts, 23 kinds of extracts showed potent inhibitory activity of NO production above 60% at the concentration of 80 micro g/ml. Some of potent extracts showed dose dependent inhibition of NO production of LPS-activated macrophages at the concentration of 80, 40, 20 micro g/ml. Especially, Artemisia iwayomogi, Machilus thunbergii, Populus davidiana and Populus maximowiczii showed the most potent inhibition (above 70%) at the concentration of 40 micro g/ml. Inhibitory activity of NO production was concentrated to nonpolar solvent fractions (ethyl ether and/or ethyl acetate soluble fractions) of Artemisia iwayomogi, Machilus thunbergii and Morus bombycis. These plants are promising candidates for the study of the activity-guided purification of active compounds and would be useful for the treatment of inflammatory diseases and endotoxemia accompanying overproduction of NO.     

Screening and comparison of antioxidant activity of solvent extracts of herbal medicines used in Korea

The hexane, ethylacetate, n-butanol, and water extracts of 10 Korean herbal medicines were screened and compared for their antioxidant activities in a range of lipid peroxidation system using rat brain homogenates, antihemolysis assay of red blood cells, and other in vitro assays to determine their ability to scavenge superoxide and hydroxyl radicals. All of the 10 Korean herbal medicines have potent antioxidant activities. Among the four solvent extracts, the antioxidant activities of more-polar solvent extracts (BuOH and water extracts) were relatively higher than that of non-polar solvent extracts (hexane and EtOAC extracts). These results will be useful to further analyze those herbal medicines that contain the most antioxidant activity in order to identify the active principles.     

12种中药的水及乙醇提取液对酪氨酸酶抑制作用的比较

[目的]比较12种常用美白中药70%乙醇提液与水提液对酪氨酸酶活性的抑制能力。[方法]利用受试物抑制蘑菇酪氨酸酶催化底物(L-多巴)发生反应从而减少黑色素生成的原理,以维生素C作标准对照,用分光光度计测定反应液在475 nm的吸光度,通过吸光度比较各受试物对酪氨酸酶活性的抑制能力。[结果]12种中药均对无细胞系蘑菇酪氨酸酶活性有不同程度的抑制作用,其中甘草等5种中药的70%乙醇提物对酪氨酸酶的抑制作用强于其水提物的抑制作用;桑叶等7种中药的水提物对酪氨酸酶的抑制作用强于其醇提物的抑制作用。[结论]通过对比常用美白中药的醇、水提取物对酪氨酸酶活性的抑制作用,筛选天然物作为纯天然美白化妆品原料,拥有广阔的发展前景。     

Screening of Thai medicinal plant extracts and their active constituents for in vitro antimalarial activity

To discover antimalarial substances from plants cultivated in Thailand 80%-EtOH extracts from selected plants were screened for in vitro antimalarial activity against the drug resistant K1 strain of Plasmodium falciparum. In total, 86 Thai medicinal plant samples representing 48 species from 35 genera in 16 families were screened and two species (Polyalthia viridis and Goniothalamus marcanii) were found to show notable antimalarial activity (IC50: 10.0 and 6.3 microg/mL). Marcanine A and 16-hydroxycleroda-3,13(14)Z-dien-15,16-olide were identified as the respective major active constituents in P. viridis and G. marcanii, respectively.     

中药复方功效的研究与发展

功效是在传统中医药理论基础上对中药复方临床作用的总结,是复杂化学活性成分多靶点、多途径的药理作用而表现出来的临床疗效,是目前研究的热点之一。该文通过对传统中药复方功效发展,中药复方对症功效,复方功效与药理效应关系,复方功效相关物质基础研究及评价等不同方面问题的探讨,分析和总结了中药复方功效的研究与发展过程中主要研究方法及存在的问题,同时对一些需要关注的问题进行了较为深入的阐述,旨在为中药复方新药功效的临床和实验研究提供参考,提高中药复方新药的研发水平,促进中医药现代化的发展。     

中草药及其活性成分抗肿瘤的研究进展

查阅国内外相关文献，综述中草药及其活性成分抗肿瘤方面的研究进展。根据中草药及其天然活性成分所诱发的不同生物效应将其抗肿瘤作用分为11类进行了详细介绍，展示了中草药用于防癌、抗癌的巨大潜能和美好前景。     

Butanolides from Machilus thunbergii and their inhibitory activity on nitric oxide synthesis in activated macrophages

In activated macrophages the inducible form of nitric oxide synthase (iNOS) generates high amounts of the toxic mediator, nitric oxide (NO), that contributes to the circulatory failure associated with septic shock. Three butanolides were isolated from Machilus thunbergii as active principles which inhibit the production of NO in lipopolysaccharide-activated RAW 264.7 cells, and their structures were identified as litsenolide A2 (1), B1 (2) and B2 (3). They showed dose-dependent inhibition of NO syntheses and the IC(50)s were 3.36, 3.70 and 6.19 micro m, respectively. These new inhibitors of iNOS may have potential in the treatment of endotoxaemia and inflammation accompanied by the overproduction of NO.     

In vitro antiplasmodial activity of extracts of Alchornea cordifolia and identification of an active constituent: ellagic acid

Extracts of leaves of Alchornea cordifolia were studied for their antiplasmodial activities. Chloroformic and ether extracts were found to be inactive while the ethanolic extract exhibited mild in vitro activity against Plasmodium falciparum. Fractionation of this extract led us to isolate ellagic acid as the active constituent of the extract with IC(50) in the range of 0.2-0.5 microM. Cytotoxicity of ethanolic fraction and ellagic acid was also estimated on human fibroblasts cells (IC(50) on Hela cells = 7.3 microM at 24 h for ellagic acid).     

Steroids and flavonoids from Physalis alkekengi var. franchetii and their inhibitory effects on nitric oxide production

Four new steroidal compounds possessing a rare 13,14-seco-16,24-cycloergostane skeleton, physalin Y ( 1), physalin Z ( 2), physalin I ( 6), and physalin II ( 7), were isolated from the 80% EtOH extract of calyces from Physalis alkekengi var. franchetii together with 11 known steroids ( 3- 5 and 8- 15) and eight flavonoids ( 16- 23). The structures of the new compounds were elucidated primarily on the basis of 1D and 2D NMR and mass spectroscopic studies. The relative configuration of the 3-OH group of 3, 4, and 5 was also established or re-established. The inhibitory effects of compounds 1- 23 on nitric oxide production in lipopolysaccaride-activated macrophages were evaluated.     

Staminane- and isopimarane-type diterpenes from Orthosiphon stamineus of Taiwan and their nitric oxide inhibitory activity

From the MeOH extract of Taiwanese Orthosiphon stamineus, two new staminane-type diterpenes, staminols C (1) and D (2), and three new isopimarane-type diterpenes, orthosiphonone C (3) and D (4) and 14-deoxo-14-O-acetylorthosiphol Y (5), have been isolated together with 16 known diterpenes, orthosiphols A, B, D, K, M, N, O, X, and Y, nororthosiphonolide A, neoorthosiphol B, orthosiphonone A, secoorthosiphols B and C, 3-O-deacetylorthosiphol I, and 2-O-deacetylorthosiphol J. Their structures were determined on the basis of the spectroscopic data. All the newly isolated diterpenes exhibited dose-dependent inhibition of nitric oxide (NO) production in lipopolysaccharide (LPS)-activated macrophage-like J774.1 cells, and 2-O-deacetylorthosiphonone A showed the most potent activity, with an IC(50) value of 35.0 microM, comparable to that of the positive control N(G)-monomethyl-L-arginine (L-NMMA; IC(50), 35.7 microM).     

Screening for antimicrobial activity of crude drug extracts and pure natural products from Mexican medicinal plants.

Preliminary antimicrobial screening against Candida albicans and selected Gram-positive and Gram-negative bacteria of methanol extracts prepared from eight Mexican medicinal plants, noted for their antiseptic properties, was conducted. The significant activity exhibited for extracts of Ratibida latipalearis, Teloxys graveolens, Dodonaea viscosa, Hyptis albida, H. pectinata, H. Suaveolens and H. verticillata tends to support their traditional use as anti-infective agents. Only the extract of Hintonia latiflora was inactive. The antimicrobial activities of 44 pure natural compounds and two derivatives were determined. Of these, only 23 compounds were effective in inhibiting the growth of the tested organisms (MIC less than or equal to 100 micrograms/ml).     

蛇足石杉内生真菌抗乙酰胆碱酯酶活性筛选及分类鉴定

目的:从蛇足石杉Huperzia serrata(Thunb.ex Murray) Trevis.内生真菌中筛选具有抗乙酰胆碱酯酶活性的菌株.方法:利用乙酰胆碱酯酶水解α-萘乙酯的产物和固蓝B盐发生显色反应的原理,用薄层色谱-生物自显影法对59株蛇足石杉内生真菌发酵产物进行抗乙酰胆碱酯酶活性筛选,并通过18s rDNA和5.8s rDNA序列分析结合形态学特征对目标菌株进行分类鉴定.结果:蛇足石杉内生真菌LQ2F01在抗乙酰胆碱脂酶活性筛选中呈现阳性颜色反应,18s rDNA和5.8s rDNA序列分析并结合形态学分类表明该菌株属枝顶孢霉属Acremonium.结论:蛇足石杉内生真菌LQ2F01表现出和宿主植物相同的抗乙酰胆碱脂酶活性,在天然药物开发以及内生真菌与宿主植物关系的研究中具有重要意义.     

Screening of Tanzanian plant extracts for their potential inhibitory effect on P-glycoprotein mediated efflux

For years, many efforts have been made to discover new drugs using plants as natural screening libraries. In this study, extracts of 43 Tanzanian medicinal plants were screened for their potential inhibitory effect on P-gp, using the secretory transport of Cyclosporin A (CsA) in the Caco-2 system as a measure of the functionality of P-gp efflux. Two out of these 43 plant extracts (extracts of Annickia kummeriae and Acacia nilotica) appeared to have a modulatory effect on P-gp related efflux carriers. In presence of the extract of Annickia kummeriae, a concentration dependent decrease on the polarity in transport of CsA was observed; the inhibitory effect of this extract on P-gp was comparable to that of valspodar, a known P-gp inhibiting agent. The exact nature of the active components of these botanicals remains to be identified.