响应面分析法优化牡丹皮中总黄酮的提取工艺

目的:采用响应面分析法优化牡丹皮中总黄酮的提取工艺。方法:固定提取时间,以乙醇浓度、料液比、提取温度为响应因子,总黄酮得率为响应值,采用3因素3水平的响应面分析法优化牡丹皮中总黄酮的提取工艺参数。结果:各因素对总黄酮提取率的影响大小依次为料液比>提取温度>乙醇浓度;牡丹皮总黄酮的最佳提取工艺条件为乙醇浓度60%,提取温度55℃,料液比1∶40(W/V),在此条件下,牡丹皮总黄酮得率为3.11mg·g-1。结论:试验结果与模型预测值相符,该工艺可用于牡丹皮中总黄酮的提取。     

葛根总黄酮提取工艺优化研究

目的优选葛根总黄酮的最佳提取工艺。方法以乙醇为提取溶剂,正交试验L9（3^4）设计对提取溶剂浓度,提取时间和料液比进行考察;选用特征峰图谱方法所测得的特征峰面积总和、葛根素转移率和固体含量作为评价指标,计算综合得分,以最终得分确定葛根总黄酮的最佳工艺条件。结果影响葛根总黄酮提取的主要因素是溶剂浓度,其次是提取时间,再次是料液比,最佳提取工艺为A2B3C2D2,即,乙醇浓度70%,提取时间3 h,提取次数2次,料液比为1∶8。结论验证试验表明最佳工艺下总黄酮提取率稳定,提取率高,提取工艺合理可行。     

正交实验法优选药用红树植物老鼠簕总黄酮提取工艺

目的以老鼠簕为对象,优选出两种黄酮提取工艺中的最佳提取条件。方法利用L_9(3~4)正交设计法优选药用红树植物老鼠簕总黄酮提取工艺,以老鼠簕总黄酮含量为指标,分别对索氏提取中的乙醇浓度、提取温度、提取时间和超声提取法中提取时间、乙醇浓度、液料比等因素进行考查,优选老鼠簕总黄酮的最佳提取条件。结果索氏提取法中,提取温度对总黄酮提取率影响最大,最佳提取条件为60%乙醇提取液,在85℃下提取2.5h。超声提取法中,乙醇浓度对提取率的影响最大,提取最佳条件为50%乙醇提取液,液料比为40:1,浸提50min,提取2次。结论超声提取方法优于索氏提取法,总黄酮提取量可达3.82%。     

正交试验优选啤酒花总黄酮提取工艺

目的:优选啤酒花总黄酮的提取工艺。方法:以乙醇浓度、料液比、提取时间、提取次数为考察因素,以总黄酮含量为指标,采用正交试验优选最佳提取工艺。结果:啤酒花总黄酮的最佳提取工艺为乙醇浓度60%、提取时间80min、料液比1∶25、提取次数3次。结论:该提取工艺简便、快捷,适用于啤酒花总黄酮的提取。     

连翘花中总黄酮提取工艺的优化

目的:研究连翘花中总黄酮的最佳提取工艺。方法:采用正交试验设计,对影响连翘花中总黄酮提取工艺的因素进行了系统考察。通过单因素试验,以总黄酮得率为指标,分别考察了乙醇体积分数、料液比、提取时间、提取次数对提取率的影响,并以此四因素为指标,设计正交试验以确定最佳提取工艺。结果:影响连翘花中总黄酮提取率的主次因素依次为:乙醇体积分数>提取次数>提取时间>料液比,其中提取次数、乙醇体积分数和提取时间有显著影响,最佳提取工艺条件为:用14倍量的70%乙醇,超声提取2次,每次30 min。结论:该提取工艺简便、快捷,适用于连翘花中总黄酮的提取。     

橡皮树叶总黄酮提取工艺及清除·OH自由基能力的研究

目的 优化橡皮树叶中总黄酮的最佳提取工艺.方法 在进行单因素试验的基础上,以乙醇浓度、料液比、提取温度、提取时间作为因素,进行L<,9>(3<'4>)正交试验.结果 各因素对提取橡皮树叶总黄嗣的影响为:料液比>提取潼度>提取时间>乙醇浓度;提取总黄酮的最佳工艺为1:6的50%乙醇70℃提取120min.在该工艺条件下,...     

枸骨叶总黄酮超声提取及含量测定

目的:优选枸骨叶总黄酮最佳提取工艺。方法:以乙醇浓度、超声时间、提取温度、料液比为考察因素,以总黄酮含量为考察指标,采用L9(34)正交试验优选最佳提取工艺。结果:最佳提取工艺为乙醇浓度40%、超声25min、温度70℃、料液比1∶12;枸骨叶总黄酮含量为4.381%(以100g干枸骨叶计)。结论:该提取工艺简便、快捷,适用于枸骨叶总黄酮的提取。     

响应面法优化凤尾草总黄酮提取工艺

目的优化凤尾草总黄酮的最佳超声提取工艺。方法以总黄酮得率为指标,采用响应面设计方法对乙醇浓度、超声时间及料液比进行优化。结果各因素对总黄酮提取率的影响大小依次为:液料比>乙醇浓度>超声时间。最佳工艺条件为:采用65%乙醇,液料比35∶1,超声时间34 min,在此最佳提取条件下,凤尾草总黄酮提取率为9.55%,试验结果与模型预测值相符。结论超声提取方法简单,提取效率高、时间短、无需加热,是一种较理想的提取凤尾草总黄酮的方法 。     

超声提取三叶青总黄酮工艺研究

目的：为优化三叶青中主要活性成分总黄酮的提取工艺。方法以提取时间、料液比、乙醇浓度和提取温度为试验因素,三叶青中总黄酮提取率为考察指标,在单因素试验基础上,采用响应面设计方法,对三叶青中总黄酮的提取工艺条件进行优化。结果试验确定最佳提取工艺为：20倍量60％乙醇,60℃下超声提取44min。在此工艺条件下,总黄酮提取率为5．55％。结论经验证,采用响应曲面法优选出的工艺稳定,为进一步研究三叶青提供参考依据。     

超声法与连续回流法提取黄芪总黄酮的工艺对比研究

目的:对比研究超声法和连续回流法提取黄芪总黄酮的工艺。方法:以乙醇浓度、提取时间、固液比、提取温度为考察因素,黄芪总黄酮提取率为考察指标,采用正交试验优选最佳提取工艺条件。结果:要获得相同的提取率,超声法效率更高,其最佳提取工艺为乙醇浓度75%,超声提取时间20min,固液比1∶10,超声提取温度25℃,提取率为0.325%。结论:与连续回流法比较,采用超声法提取黄芪总黄酮具有快速、节省溶剂、提取的有效成分含量高等优点。     

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.     

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.     

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.     

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.     

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.     

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.     

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.     

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.     

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.