抱茎苦荬菜的化学成分及其抗氧化活性

目的 对菊科(Compositae)苦荬菜属 (Ixeris)植物抱茎苦荬菜正丁醇萃取层中的化学成分进行分离与鉴定。 方法 采用反复硅胶柱色谱﹑重结晶、Sephadex LH-20柱色谱﹑开放ODS柱色谱、HPLC等方法进行分离纯化以获得单体化合物。通过理化性质及波谱数据鉴定这些单体化合物的化学结构,利用1,1-二苯基-2-三硝基苯肼(DPPH)和2,2-联氮基-双-(3-乙基苯并噻唑啉-6-磺酸)二氨盐(ABTS)法评价这些化合物清除自由基的活性。 结果 从抱茎苦荬菜正丁醇萃取层中分离得到5个化合物,分别鉴定为(+)-松脂素-4-O-β-D-葡萄糖苷(1)、glochidioboside (2)、3,4,5-trimethoxyphenyl-1-O-β-D-glucopy-ranoside(3)、芒柄花苷(4)、大豆素(5)、木犀草素(6)、芹菜素(7)。利用DPPH和ABTS法测试了这7个化合物清除自由基的活性。 结论 化合物 1 ~ 5 为首次从苦荬菜属植物中分离得到,化合物 1 、 2 、 4 ~ 7 显示了较强的自由基清除活性。     

海南红树林内生真菌Fusarium sp. HSL-3次级代谢产物研究

目的 研究海南红树林内生真菌Fusarium sp. HSL-3次级代谢产物,并对其进行抗炎和抗肿瘤活性筛选。方法 采用大米培养基对菌株静置培养,同时采用柱层析色谱法和HPLC对该真菌的次级代谢产物进行分离纯化,并且通过核磁共振及质谱等有机波谱手段,对得到的化合物进行结构鉴定。结果 共分离得到8个化合物,分别为lateritin(1)、4-carbomethoxy-6-hydroxy-2-quinolone(2)、3,5-dimethoxydihydrofusarubin D(3)、anhydrofusarbin(4)、3,3''-methylene-bis (4-hydroxybenzaldehyde)(5)、crypticin B(6)、vanillyl alcohol(7)和3,4-dihydroxyphenylaceticacid(8),其中化合物2和5为首次从镰刀菌属Fusarium中分离得到。化合物3和5对RAW264.7细胞表现出良好的抗炎活性(化合物3在50 µmol·L^-1时的NO抑制率为87%,化合物5在50 µmol·L^-1时的NO抑制率为71%),而化合物1对非小细胞肺癌细胞A549有显著的细胞毒活性,IC₅₀值为(7.92±0.27)µmol·L^-1。结论 从海南红树林内生真菌Fusarium sp. HSL-3中分离得到的化合物3和5具有较强的抗炎活性,化合物1有显著的抗肿瘤活性。     

月腺大戟的化学成分及其乳腺癌细胞毒活性研究

目的 研究大戟科植物月腺大戟的化学成分及其对乳腺癌细胞毒活性。方法 采用多种色谱技术对化合物进行分离纯化,根据化合物的理化性质和光谱数据分析鉴定化合物的结构。采用噻唑蓝（MTT）比色法研究化合物对6种乳腺癌细胞的抑制活性。结果 月腺大戟植物中分离得到10个化合物,分别鉴定为：2,4-二羟基-6-甲氧基-3-甲酰基苯乙酮（1）;2,4-二羟基-6-甲氧基-3-甲基苯乙酮（2）;月腺大戟素A（3）;3,3''-乙酰基-4,4''-二甲氧基-2,2'',6,6''-四羟基二苯基甲烷（4）;岩大戟内酯B（5）;岩大戟内酯A（6）;亚油酸（7）;fischeria A（8）;β-香树脂醇乙酸酯（9）;单十九酸甘油酯（10）。乳腺癌细胞毒活性研究显示：化合物3对乳腺癌细胞MDA-MB-231、Sum149、MCF7、ZR-75-1、SKBr3、BT474的IC₅₀值分别为6.69、5.50、5.50、7.08、8.64、5.42 μmol/L。结论 化合物6、7、8、10为首次从该植物中分离得到;化合物3对乳腺癌细胞具有显著的抑制活性。     

紫茎泽兰中的萜类成分研究

目的 对紫茎泽兰中的萜类成分及其药理活性进行研究。方法 采用D101、HP20大孔树脂、硅胶柱色谱、葡聚糖凝胶色谱、高效液相色谱等多种分离分析手段，MS、¹H-NMR和¹³C-NMR等多种波谱技术以及ECD计算鉴定化合物结构，并采用MTT法对分离得到的单体化合物进行细胞毒活性的筛选。结果 从紫茎泽兰95%乙醇提取物的石油醚和乙酸乙酯萃取部位中分离得到10个化合物，分别鉴定为泽兰酮D (1)、thymoquinol 5-O-β-glucopyranoside (2)、thymoquinol2-O-β-glucopyranoside (3)、2R^*,3S^*-toxol-7-O-β-D-glucopyranoside (4)、6-甲氧基-山柰酚-7-O-β-D-葡萄糖苷(5)、万寿菊素-4’-甲氧基-7-O-β-D-葡萄糖苷(6)、6-hydroxykaempferol-7-O-β-D-glucopyranoside (7)、eupatonriochromene (8)、demethoxyencecalin (9)、encecalin (10)。化合物10对食管癌细胞的IC₅₀值为178.4 μmol·L^-1。结论 其中化合物1为新化合物，化合物6为首次从泽兰属中分离得到，化合物2，3，7为首次从紫茎泽兰中分离得到。化合物10对食管癌细胞Eca-109具有一定的细胞毒活性。     

槲寄生内生菌IA-4-2及其代谢产物的分离、鉴定和神经氨酸酶抑制作用考察

摘 要 目的：研究对神经氨酸酶具有抑制作用的槲寄生内生菌次生代谢产物。方法: 采用AB 8大孔吸附树脂、C₁₈-SPE柱层析结合制备型HPLC等手段进行分离纯化,根据GC-MS和HPLC等分析手段确定化合物结构,并且利用神经氨酸酶抑制药筛选试剂盒测定活性。结果: 从槲寄生内生菌IA 4 2中获得对神经氨酸酶具有较强抑制作用的化合物,经结构鉴定为吲哚-3-甲醛,其对神经氨酸酶的 IC₅₀为128.2 μg?ml^-1。结论:槲寄生内生菌次生代谢产物吲哚-3-甲醛对神经氨酸酶抑制作用明显,值得进一步研究。     

白益母草中酚苷类化合物的分离鉴定及其体外抗氧化活性评价

目的 分离鉴定白益母草中抗氧化活性成分。方法 采用常规回流提取法先以二氯甲烷对白益母草脱脂，然后药渣用乙酸乙酯提取得到其提取物。乙酸乙酯提取物利用硅胶、葡聚糖凝胶柱色谱及HPLC进行分离，分离得到化合物经波谱学数据分析，确定其结构式。同时，利用1，1-二苯基-2-三硝基苯肼（DPPH）法测定分离得到化合物的抗氧化活性。结果 从白益母草乙酸乙酯提取物中分离得到4个酚苷类化合物，分别为毛蕊花苷（1），5，7，4''-三羟基黄酮-7-O-（6″-O-[E]-香豆酰基）-β-葡萄糖苷（2），5，7，4''-三羟基黄酮-7-O-（6″-O-[E]-咖啡酰基）-β-葡萄糖苷（3）和5，7，4''-三羟基黄酮-7-O-（6″-O-[E]-二香豆酰基）-β-葡萄糖苷（4）。化合物1~4表现出较好的抗氧化活性，其EC₅₀平均值分别为（19.5±1.81），（26.2±3.4），（22.9±2.7），（24.4±3.1）。结论 化合物1~4均为首次从该药材中分离得到，可作为天然抗氧化剂。     

极地海绵共附生放线菌Streptomyces sp. LHW11-07次生代谢产物研究

目的 对极地海绵共附生放线菌Streptomyces sp. LHW11-07进行次生代谢产物的研究,以期得到结构新颖且具有良好生物活性的小分子化合物。方法 综合运用凝胶柱色谱、硅胶柱色谱、反相中压柱色谱和高效液相色谱等分离手段对Streptomyces sp. LHW11-07发酵产物进行分离和纯化,采用质谱、一维、二维核磁共振等现代波谱方法并结合相关文献调研鉴定它们的结构。结果 从该菌的发酵产物中共分离得到9个单体化合物,分别为cyclo-(L-Tyr-L-Trp) (1)、cyclo-(L-Trp-L-Ser) (2)、cyclo-(D-Tyr-D-Pro) (3)、cyclo-(L-Tyr-L-Phe) (4)、cyclo-(L-Tyr-L-Leu) (5)、albaflavenol B (6)、β-adenosine (7)、N-formylantimyic acid methyl ester (8)和conglobatin A (9)。结论 化合物1和2是首次分离于Streptomyces属放线菌。     

海绵共附生菌Streptomyces sp. LHW2432的次级代谢产物研究

目的 从海绵共附生菌Streptomyces sp. LHW2432的发酵产物中发现药用活性分子。方法 采用正向硅胶柱、ODS反向柱以及高效液相色谱分离技术,对LHW2432的发酵萃取物进行分离纯化;通过现代波谱技术和文献调研确定化合物结构;利用平板涂布法和微量稀释法,评价化合物对芽胞杆菌、耐甲氧西林金黄色葡萄球菌（MRSA）、耻垢分支杆菌、白色念珠菌和大肠杆菌的抑菌活性。结果 从LHW2432发酵物中共分离鉴定了5个化合物：descycloavandulyl-lavanduquinocin (1)、N-acetyltyramine (2)、phomapyrone C (3)、germicidin A (4) 和germicidin I (5)。化合物1对MRSA和耻垢分支杆菌的最小抑菌浓度（MIC）值分别为100和64 μg/ml。结论 从LHW2432菌中分离得到5个化合物,其中,化合物1是新天然产物,可作为神经保护活性三环咔唑类生物碱的合成前体,其对G⁺菌有微弱的抑制活性。     

黄三七化学成分的研究

目的 研究黄三七的化学成分。方法 采用多种色谱方法对黄三七全草的乙醇提取物进行分离纯化,并应用现代波谱技术对得到的化合物进行结构鉴定。结果 共分离得到6个环菠萝蜜烷型三萜类化合物,分别鉴定为cimilactoneA(1)、23-Epi-26-deoxyactein(2)、soulieosides I(3)、neocimicigenoside B(4)、asiaticoside A(5)、25-O-acetylcimigenol-3-O-β-D- xylopyranoside(6)。结论 环菠萝蜜烷型三萜类化合物是黄三七的特征性成分,化合物1、4和5为首次从该属植物中分离得到。     

一株海洋来源Streptomyces sp. SCSIO 1682中那西肽(nosiheptide)的分离鉴定及其生物合成基因簇分析

目的 对一株海洋来源的菌株SCSIO 1682进行16S rDNA分子生物学鉴定,对发酵产物中的抑菌活性化合物进行分离鉴定,并对抑菌活性化合物的生物合成基因簇进行分析。方法 通过构建基于16S rDNA序列的系统发育树来进行菌株鉴定;通过有机溶剂萃取、正相和反相硅胶层析等化学分离手段对菌株SCSIO 1682的次级代谢产物进行活性追踪分离纯化;运用HR-ESI-MS,₁H和₁₃C NMR等波谱手段对所得化合物进行结构解析;通过对菌株SCSIO 1682进行全基因组扫描测序鉴定所得化合物的生物合成基因簇。结果 该菌株被鉴定为Streptomyces sp. SCSIO 1682,所得抑菌活性化合物为那西肽,鉴定了那西肽的生物合成基因簇并进行生物信息学分析。结论 从海洋链霉菌Streptomyces sp. SCSIO 1682中分离鉴定了那西肽,那西肽生物合成基因簇的鉴定为利用组合生物合成和合成生物学技术对那西肽进行结构改造提供了新的基因资源。     

Genetic regulation of the ramA locus and its expression in clinical isolates of Klebsiella pneumoniae

Tigecycline resistance has been attributed to ramA overexpression and subsequent acrA upregulation. The ramA locus, originally identified in Klebsiella pneumoniae, has homologues in Enterobacter and Salmonella spp. In this study, we identify in silico that the ramR binding site is also present in Citrobacter spp. and that Enterobacter, Citrobacter and Klebsiella spp. share key regulatory elements in the control of the romA-ramA locus. RACE (rapid amplification of cDNA ends) mapping indicated that there are two promoters from which romA-ramA expression can be regulated in K. pneumoniae. Correspondingly, electrophoretic binding studies clearly showed that purified RamA and RamR proteins bind to both of these promoters. Hence, there appear to be two RamR binding sites within the Klebsiella romA-ramA locus. Like MarA, RamA binds the promoter region, implying that it might be subject to autoregulation. We have identified changes within ramR in geographically distinct clinical isolates of K. pneumoniae. Intriguingly, levels of romA and ramA expression were not uniformly affected by changes within the ramR gene, thereby supporting the dual promoter finding. Furthermore, a subset of strains sustained no changes within the ramR gene but which still overexpressed the romA-ramA genes, strongly suggesting that a secondary regulator may control ramA expression.     

Toxicity assessment of crude and partially purified extracts of marine Synechocystis and Synechococcus cyanobacterial strains in marine invertebrates

Among the Cyanoprokaryota, the genera Synechocystis and Synechococcus have rarely been studied with respect to potential toxicity. This is particularly true with marine environments where studies about the toxicity of cyanobacteria are restricted to filamentous forms at the warmer temperate and tropical regions and also to filamentous forms at cold seas such as the Baltic Sea. In this study, we describe the effects of cyanobacterial strains of the Synechocystis and Synechococcus genera isolated from the marine coast of Portugal, on marine invertebrates. Crude and partially purified extracts at a concentration of 100 mg/ml of freeze-dried material of the marine strains were tested for acute toxicity in nauplii of the brine shrimp Artemia salina, in the rotifer Brachionus plicatillis and in embryos of the sea urchin Paracentrotus lividus and the mussel Mytilus galloprovincialis. The cyanobacterial extracts, especially the crude extract, had an impact on A. salina nauplii. No significant toxic effects were registered against the rotifer. A negative impact of all strains was recorded on the embryonic development of the sea urchin, with toxic effects resulting in an inhibition of embryogenesis or development of smaller larvae. To the mussel embryos, the effects of cyanobacterial extracts resulted in a complete inhibition of embryogenesis. The results of all assays indicate that Synechocystis and Synechococcus marine strains contained toxic compounds to marine invertebrates.     

In vitro Studies of Antimicrobial Activity of Crude Extracts of the Indian Grasses Dhaman (Cenchrus ciliaris) and Kala-Dhaman (Cenchrus setigerus)

The aim of present study was to investigate the antimicrobial activity of Cenchrus ciliaris and Cenchrus setigerus extracts in order to use it as a possible source for new antimicrobial substances against important human pathogens. Crude extracts of the stem of Cenchrus ciliaris and Cenchrus setigerus were evaluated against some medically important pathogens viz. Escherichia coli, Raoultella planticola, Staphylococcus aureus, Pseudomonas aeruginosa, Bacillus subtilis, Enterobacter aerogenes, Candida albicans and Aspergillus flavus. The dried and powdered stems were successively extracted with hexane, toluene, isopropyl alcohol, acetone and ethanol using soxhlet assembly. The antimicrobial activity assay was done by both disc diffusion and serial dilution methods. Isopropyl alcohol extract of Cenchrus setigerus showed highest activity against Escherichia coli. The test pathogens were more sensitive to the isopropyl alcohol, acetone and ethanol extracts than to the hexane and toluene extracts except against Bacillus subtilis. Result reveals that the most bioactive compound was cycloleucolenol-9,19-cycloergost-24 (28)-en-3-ol, 4, 14-dimethyl acetate in both the species of Cenchrus grass, (19.15%) in isopropanol extract of Cenchrus setigerus whereas, (14.03%) in acetone extract of Cenchrus ciliaris.     

Hormetic Responses of Lonicera Japonica Thunb. To Cadmium Stress

The hormetic responses of Lonicera japonica Thunb. to cadmium (Cd) stress were investigated in a hydroponic experiment. The present results showed that root length and total biomass dry weight increased in comparison with the control at low concentrations Cd. The height of the plant exposed to 2.5 and 5 mg L^-1 Cd increased significantly by 11.9% and 12.8% relative to the control, and with the increase of Cd concentrations in the medium, plant height began to decrease. The responses of photosynthetic pigments contents and relative water content to Cd stress had a similar trend, which all showed significantly an inverted U-shaped dose–response curve and confirmed that the stimulatory effect of low concentrations Cd occurred in the plant. Furthermore, L. japonica, as a new Cd-hyperaccumulator, could be considered as a new plant model to study the underlying mechanisms of the hormesis.     

Cytotoxic fungi--an overview.

Among fungal toxins causing organ damage in the human body, amatoxins and orellanine remain exceptional. Amatoxins, a group of bicyclic octapeptides occurring in some Amanita, Galerina and Lepiota species, induce deficient protein synthesis resulting in cell death, but might also exert toxicity through inducing apoptosis. Target organs are intestinal mucosa, liver and kidneys. Poisoning will result in dehydration and electrolyte derangement, liver necrosis and possibly kidney damage. In established poisoning the mainstay of treatment is optimum symptomatic and supportive care. No specific treatment is available, but some pharmaceuticals, like silibinin, benzylpenicillin and acetylcysteine, might have a role in limiting the extent of hepatic damage. Orellanine is a nephrotoxic bipyridine N-oxide found in some Cortinarius species. Its mechanism of action is not fully understood, but it has been shown to inhibit protein synthesis and to generate free oxygen radicals. As early symptoms often are lacking or vague, poisoning may initially be overlooked or misinterpreted and the patients usually present with established renal damage. Supportive care is the only therapeutic option. Tricholoma equestre might contain a myotoxin and repeated ingestion may cause significant rhabdomyolysis. Ingestion of Amanita smithiana and A. proxima has been reported to result in kidney damage. Gyromitrin, a toxic compound that is converted to hydrazines in the stomach, occurs in some Gyromitra species. It is mainly neurotoxic, but may also induce moderate hepatic damage and haemolysis.     

Effect of Plant Extracts Formulated in Different Ointment Bases on MDR Strains

Extracts of Aloe vera whole plant, Eucalyptus globulus leaves, Ficus infectoria bark, Ficus religiosa bark and Piper betel leaves were studied for antibacterial activity on resistant and sensitive strains, isolated from skin and soft tissue infections. A combination of hot alcoholic extracts of Ficus infectoria, Ficus religiosa and Piper betel were found to be more effective against all the isolates. The combined extract was formulated in different ointment bases such as polyethylene glycol, gelatin, sodium alginate, carbopol, cream base and honey. These were then evaluated to find a suitable base for preparation of an ointment. In vitro study of the release of antimicrobials and kill-time studies of the herbal ointments was carried out against multi-drug resistant isolate of Pseudomonas. The ointment showed bactericidal activity within 2 h against the resistant strain of Pseudomonas spp.     

Toxic dinoflagellates (Dinophyceae) from Rarotonga, Cook Islands

Dinoflagellate species isolated from the green calcareous seaweed, Halimeda sp. J.V. Lamouroux, growing in Rarotongan lagoons, included Gambierdiscus australes Faust & Chinain, Coolia monotis Meunier, Amphidinium carterae Hulburth, Prorocentrum lima (Ehrenberg) Dodge, P. cf. maculosum Faust and species in the genus Ostreopsis Schmidt. Isolates were identified to species level by scanning electron microscopy and/or DNA sequence analysis. Culture extracts of G. australes isolate CAWD149 gave a response of 0.04 pg P-CTX-1 equiv. per cell by an N2A cytotoxicity assay (equivalent to ca 0.4 pg CTX-3C cell⁻¹). However, ciguatoxins were not detected by LC-MS/MS. Partitioned fractions of the cell extracts potentially containing maitotoxin were found to be very toxic to mice after intraperitoneal (i.p.) injection. A. carterae was also of interest as extracts of mass cultures caused respiratory paralysis in mice at high doses, both by i.p. injection and by oral administration. The Rarotongan isolate fell into a different clade to New Zealand A. carterae isolates, based on DNA sequence analysis, and also had a different toxin profile. As A. carterae co-occurred with G. australes, it may contribute to human poisonings attributed to CTX and warrants further investigation. A crude extract of C. monotis was of low toxicity to mice by i.p. injection, and an extract of Ostreopsis sp. was negative in the palytoxin haemolysis neutralisation assay.     

Structure-Based Design of Substituted Piperidines as a New Class of Highly Efficacious Oral Direct Renin Inhibitors

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Immunomodulatory Effects of Triphala and its Individual Constituents: A Review

The role of plant extracts and Ayurvedic polyherbal preparations in treating various ailments has been acknowledged since time immemorial. Studies based on the effect of these extracts in treatment of different diseases have also been well documented. Indian medicinal literature also emphasizes the synergistic effect of polyherbal drugs in restoring and rejuvenating immune system. This review focuses on the immunomodulatory potential of the polyherbal preparation, Triphala and its three constituents, Terminalia bellerica, Terminalia chebula and Emblica officinalis. The role of Triphala and its extract has been emphasized in stimulating neutrophil function. Under stress condition such as noise, Triphala significantly prevents elevation of IL-4 levels as well as corrects decreased IL-2 and IFN-γ levels. Under the condition of inflammatory stress its immunosuppressive activity is attributed to its inhibitory action on complement system, humoral immunity, cell mediated immunity and mitogen-induced T-lymphocyte proliferation. The aqueous and alcoholic extracts of the individual constituents reportedly enhance especially the macrophage activation due to their free radical scavenging activity and the ability to neutralize reactive oxygen species. This study thus concludes the use of Triphala and its three individual constituents as potential immunostimulants and/or immunosuppressants further suggests them to be a better alternative for allopathic immunomodulators.     

Toxigenicity of enniatins from Western Australian Fusarium species to brine shrimp (Artemia franciscana)

The high prevalence (14 of 24 isolates) of enniatin-producing isolates from Western Australian Fusarium species isolated from pasture legumes associated with sheep feed refusal and rat deaths, and the high toxicity of their crude extracts to brine shrimp (Artemia franciscana) from a previous study warranted further investigation of this class of mycotoxin. Crude extracts from Fusarium acuminatum, Fusarium avenaceum, Fusarium tricinctum and Fusarium sambucinum, along with enniatins A, A1, B and B1 purified from a Western Australian strain of F. acuminatum using semi-preparative HPLC, were bioassayed using brine shrimp. All Fusarium isolates produced both enniatins B and B1, except for F. tricinctum WAC 8019, and 11 of the 17 isolates produced enniatin A1. Overall, all of the F. avenaceum isolates produced high amounts of enniatins, in particular enniatin B. One isolate of F. acuminatum (WAC 5715) and of F. tricinctum (WAC 11486) also produced high amounts of both enniatins B and B1. Only F. acuminatum WAC 5715 produced enniatin A among the tested isolates. All four purified enniatins A, A1, B, B1, individually and in combination, caused brine shrimp toxicity after 6 h of exposure, implicating that this emerging class of mycotoxin as a cause of the acute toxicity to brine shrimp observed. The mixture of all four enniatins was the most toxic to brine shrimp compared to purified individual enniatins, where the relative toxicity order was B > B1 > A1 > A. Enniatin B was the individual most toxic enniatin with some bioactivity at 5 μg/mL and almost 100% brine shrimp death at 50 μg/mL after 24 h of exposure. This study is the first report to confirm the acute toxicity of enniatins A, A1, B and B1 to brine shrimp, and also highlights the need for further investigation of the potential toxicity of these cyclic hexadepsipeptides to animals and humans.