一株南海北部深海沉积环境真菌00457的鉴定及其活性研究

从南海深海沉积环境样品中分离到一株编号为00457的真菌,基于形态学特征、ITS和5.8S rDNA序列比对分析,鉴定该菌株为白黄笋顶孢霉( Acrostalagmus luteoalbus).活性研究表明,其代谢产物粗浸膏的卤虫致死活性明显,并具有一定强度的抑菌和DPPH自由基清除活性.此外,研究还发现代谢产物粗浸膏在25-100℃持续加热不超过30 min时,卤虫致死活性成分稳定,但在100C持续加热超过60 min后卤虫致死活性成分显著减少,而一定强度的紫外光照射90 min内则无显著影响.     

海洋真菌Aspergillus niger XJJ-3中萘并吡喃酮类化合物结构及生物活性

【背景】萘并吡喃酮类化合物生物活性多样,是真菌Aspergillusniger中特征次生代谢产物。【目的】研究分离自海洋滩涂土壤的真菌Aspergillus niger XJJ-3中萘并吡喃酮类化合物结构及其抗菌和卤虫致死活性。【方法】以TLC分析为导向,综合运用多种色谱和光谱方法分离和鉴定萘并吡喃酮类化合物。采用微量稀释法测试化合物的抗菌和卤虫致死活性。【结果】从真菌A.niger大米发酵产物中共分离得到6个萘并吡喃酮类化合物,鉴定为RubrofusarinB(1)、Flavasperone (2)、Aurasperone A (3)、Asperpyrones C (4)、Asperpyrones B (5)和Fonsecinone A (6)。抗菌活性实验结果表明,化合物1-6对致病菌S. aureus ATCC33591、29213、E. faecium ATCC35667和V.parahemolyticus表现出不同程度的抑制活性,其中化合物2和4对S.aureus ATCC33591表现出较强抑制活性(MIC分别为43.7μmol/L和21.9μmol/L),化合物3对E.faecium ATCC35667抑制活性较强(MIC为21.9μmol/L)。卤虫致死活性实验结果表明,化合物1-6均表现出一定的卤虫致死活性,其中化合物2和3活性显著(LD50分别为35.0μmol/L和8.8μmol/L)。【结论】菌株XJJ-3可产生结构丰富的萘并吡喃酮类化合物,化合物1-6存在不同程度的抗菌和卤虫致死活性,该研究可为抗菌和细胞毒类药物的研发提供参考。     

一株深海热液口嗜热芽孢杆菌SY27F代谢产物活性的研究

【目的】对一株来源于深海热液口嗜热芽孢杆菌的次生代谢产物进行抑菌活性和抗肿瘤活性的初步研究。【方法】采用纸片法和微量肉汤稀释法检测嗜热芽孢杆菌SY27F次生代谢产物的抑菌活性,采用CCK-8法测定其次生代谢产物的抗肿瘤活性。【结果】抑菌实验表明,嗜热芽孢杆菌代谢产物对大肠杆菌、金黄色葡萄球菌均有抑菌作用,其最低抑菌浓度分别为1.56 mg/mL和3.13 mg/mL;细胞实验表明,其代谢产物对肿瘤细胞A549、HepG2、HeLa、MCF-7均有一定的抑制作用,其半致死浓度分别为0.390、0.451、0.704、1.105 mg/mL;与人肝肿瘤细胞(HepG2)相比,其对人正常肝细胞(L02)表现出良好的生物相容性。【结论】嗜热芽孢杆菌SY27F次生代谢产物具有一定的抑菌和抗肿瘤活性,可为寻找新型抑菌抗肿瘤活性物质提供优质资源。     

中国南海部分深海沉积物真菌多样性及其抗菌活性

【目的】从南海4个站位的深海沉积物中分离真菌,揭示其多样性并测定抗菌活性。【方法】使用4种培养方法和8种培养基,从12个深海沉积物样本中分离培养真菌,通过菌落形态观察和ITS序列系统发育分析进行鉴定。采用滤纸片扩散法和生长速率法分别测试真菌小量发酵液粗浸膏的抗细菌和抗真菌活性。【结果】共分离到125株纯培养真菌,基于形态和ITS序列分析,排重后得到18个种类型,这些真菌可以划分到12个属,大多数属于子囊菌门(Ascomycota),只有2株属于担子菌门(Basidiomycota)。4个站位可培养真菌多样性具有差异性。抑菌活性筛选显示,大多数真菌具有较好的抑菌活性;链格孢属(Alternaria)、青霉属(Penicillium)、匐柄霉属(Stemphylium)这几个属的真菌表现出对多种指示细菌有抑制作用,尤其是Alternaria tenuissima DN09、Alternaria alternata DN14和Penicillium chrysogenum DN16对G~+和G~–细菌均表现出抑制作用。【结论】本研究揭示了南海深海沉积物可培养真菌多样性和抑菌活性,为进一步利用深海沉积物来源真菌奠定了基础。     

基于高通量解析和可培养技术的白蔹内生真菌类群分析及分离菌株的抗痤疮致病菌活性

【背景】药用植物蕴含丰富的内生真菌类群资源,而且内生真菌可产生与宿主相关的次级代谢产物,具有多种生物活性,是活性化合物生产的潜在经济来源。【目的】分析药用植物白蔹根部内生真菌的物种多样性,并筛选出具有抗痤疮致病菌活性的目标菌株。【方法】基于高通量和组织分离法分析白蔹内生真菌的类群结构多样性;通过琼脂扩散法对内生真菌代谢产物的抗痤疮致病菌活性进行筛选;以微量肉汤稀释法测定代谢产物的最小抑菌浓度(minimuminhibitory concentration, MIC)和最小杀菌浓度(minimum bactericidal concentration, MBC)。【结果】高通量测序结果显示,白蔹根部内生真菌可注释到8门22纲45目73科93属,根部的优势属为Tainosphaeria(20.86%)和镰刀菌属(Fusarium, 15.38%)。基于组织分离法共从白蔹根部分离获得83株内生真菌,隶属于12个属,其中青霉属(Penicillium,24.10%)、木霉属(Trichoderma,14.46%)、背芽突霉属(Cadophora, 13.25%)、镰刀菌属(Fusarium, ...     

杜比亚蟑螂共生真菌次生代谢产物及其生物活性

为探究杜比亚蟑螂体内共生真菌种类,测定共生真菌次生代谢产物的抑菌活性和抗氧化活性,筛选出具有抗菌和抗氧化活性的菌株,本研究采用组织块分离法分离杜比亚蟑螂体内的共生真菌,通过形态学和分子生物学相结合的方法对分离到的共生真菌进行鉴定;分别采用薄层层析-生物自显影法和DPPH法测定共生真菌次生代谢产物的抗细菌活性和抗氧化活性。结果表明,从杜比亚蟑螂体内共分离鉴定得到5种不同的共生真菌,主要分布于青霉属(1株)、曲霉属(3株)和聚孢霉属(1株)。活性测定的结果表明,菌株Bdf-2、Bdf-4和Bdf-5表现出较好的抗菌活性,且菌液提取物的抗菌活性要强于菌丝。Bdf-1,Bdf-2和Bdf-3菌液次生代谢产物表现出抗氧化活性,IC 50值分别为0.26 mg/mL、2.20 mg/mL和0.75 mg/mL。杜比亚蟑螂共生真菌以青霉属和曲霉属为主,且具有抗菌和抗氧化活性的次生代谢产物主要分布于菌液中。     

青蒿内生真菌的抗肿瘤抗氧化活性

采用MTT法和DPPH法,分别测定已分离得到的68株贵州青蒿内生真菌乙酸乙酯粗提物的肿瘤细胞生长抑制率和DPPH自由基清除率。试验共筛选获得12株活性内生真菌,根据其形态特征进行鉴定,分别隶属于子囊菌亚门(Ascomycotina)的链格孢属(Alternaria)、刺盘孢属(Colletotrichum)、拟盘多毛孢属(Pestalotiopsis)和拟茎点霉属(Phomopsis);其中,有8株内生真菌至少对1种指示瘤株具有细胞毒活性,占总菌株数的11.8%;5株内生真菌具有不同程度的清除DPPH自由基活性,占总菌株数的7.4%;1株内生真菌同时具有细胞毒活性和抗氧化活性。     

南海珊瑚来源真菌Aspergillus sp.SCSIO 40435的分离鉴定及其次级代谢产物研究

【目的】南海珊瑚共附生真菌Aspergillus sp. SCSIO 40435次级代谢产物分离鉴定及抑菌活性筛选。【方法】利用稀释涂布平板法分离珊瑚共附生真菌。采用单菌多代谢产物方法(one strain many compounds,OSMAC)对分离菌株进行化学多样性筛选,并采用滤纸片扩散法对真菌发酵产物进行抑菌活性分析。通过ITS测序鉴定活性菌株SCSIO 40435的分类地位,运用多种色谱手段从其粗提物中分离纯化单体化合物,并利用各种波谱手段(HRESIMS、1D和2D NMR、单晶X-ray衍射法等)确定化合物的结构。最后,采用微量肉汤稀释法对单体化合物的抑菌活性进行评估。【结果】从南海珊瑚样品中分离得到19株共附生真菌,结合化学多样性和抑菌活性分析,筛选出1株产物丰富且具有多种抑菌活性的菌株SCSIO40435。利用ITS测序分析将其鉴定为曲霉属真菌(Aspergillus sp.),进一步从其发酵产物中分离鉴定了4个对三联苯类化合物：dicandidusin A(1)、candidusin A(2)、terphenyllin(3)和4″-deoxyterphenylli...     

一株海洋链霉菌MMHS020的抗菌活性代谢产物

【背景】海洋微生物因其生存环境的多样性与独特性,已成为天然产物研究的重要来源。【目的】以一株太平洋海泥来源链霉菌MMHS020为出发菌株,筛选可促进其产生丰富代谢产物的发酵条件,挖掘菌株在抗菌抗肿瘤方面的潜力。【方法】采用单菌株多次级代谢产物策略对MMHS020菌株进行培养诱导,使其产生更丰富的活性代谢产物。双层平板法测定发酵产物对6种指示菌的抑菌活性。以硅胶柱层析、葡聚糖凝胶层析和制备层析等方法对代谢产物进行分离纯化,再通过质谱技术和~1H-NMR和~(13)C-NMR对化合物进行结构解析。【结果】链霉菌属MMHS020菌株可在较高浓度盐离子环境中产生丰富的抑菌活性代谢产物,显示出对枯草芽孢杆菌、结核分枝杆菌和藤黄微球菌等多种指示菌的抑制活性。从发酵产物中分离鉴定了3个化合物,分别是诺卡胺素(1)、麦角甾醇(2)和星形孢菌素(3)。其中星形孢菌素表现出白色念珠菌的抑制活性,而诺卡胺素则对其他几个指示菌表现出较强的抑制活性。【结论】海洋链霉菌MMHS020菌株可代谢产生丰富多样的生物活性物质,具有开发成为新型抑菌生物制剂的潜力。     

飞龙斩血内生菌种群分布及抑菌活性检测

【目的】研究药用植物飞龙斩血内生菌的种群组成及其抑菌活性,以了解飞龙斩血内生菌的种群分布状态和得到抗菌活性菌株。【方法】采用严格的表面消毒程序、添加抑菌剂的方法分离、培养内生菌株。利用表型和分子技术相结合的方法对内生菌进行分类鉴定。纸片扩散法对分离获得的内生菌进行抑菌活性试验。【结果】从飞龙斩血植株内分离得到了3株内生细菌,1株内生放线菌和82株内生真菌。分类鉴定为14目16科27属,镰孢属(Fusarium)、拟盘多毛孢属(Pestalotiopsis)、曲霉属(Aspergillus)为飞龙斩血内生真菌中的优势种群。通过对30株病原指示菌的抑菌活性检测,18株内生菌对多种指示菌有明显的抑制作用。16株是内生真菌,分属11属。【结论】本试验研究了飞龙斩血内生菌的种群分布,获得了一些具有抗菌活性的内生菌,为飞龙斩血内生菌资源的开发利用提供了基础。     

沙蜇(Stomolophus meleagris)刺丝囊毒素生物活性的初步分析

从沙蜇触手提取刺丝囊细胞毒素,并对该毒素进行溶血活性、致死活性、SOD活性和抗肿瘤活性的研究。结果显示,沙蜇毒素具有明显的溶血活性,其半溶血率(HU50)约为10.5μg/ml;该毒素还对草鱼显示出较强的致死活性,半致死量(LD50)为50μg毒素/g鱼;同时该毒素具有明显的SOD活性和抗肿瘤活性,当毒素浓度为18μg/ml时其总SOD活性为161 U/mg,而毒素浓度为1 mg/ml时,该毒素对肝癌细胞Bel-7402表现出显著的抑制效果,其抑制率达到54.9%。因此,有必要对沙蜇毒素内的生物活性组分进行深入研究,为沙蜇毒素的开发利用提供依据。     

Biological activities of two macroalgae from Adriatic coast of Montenegro

In the present investigation the acetone extracts of macroalgae Ulva lactuca and Enteromorpha intestinalis were tested for antioxidant, antimicrobial and cytotoxic potential. Antioxidant activity was evaluated by measuring the scavenging capacity of tested samples on DPPH and superoxide anion radicals, reducing the power of samples and determination of total phenolic and flavonoid compounds in extracts. As a result of the study, U. lactuca extract was found to have a better free radical scavenging activity (IC₅₀ = 623.58 μg/ml) than E. intestinalis extract (IC₅₀ = 732.12 μg/ml). Moreover, the tested extracts had effective ferric reducing power and superoxide anion radical scavenging. The total content of phenol in extracts of U. lactuca and E. intestinalis was 58.15 and 40.68 μg PE/mg, while concentrations of flavonoids were 39.58 and 21.74 μg RE/mg, respectively. Furthermore, among the tested species, extracts of U. lactuca showed a better antimicrobial activity with minimum inhibitory concentration values ranging from 0.156 to 5 mg/ml, but it was relatively weak in comparison with standard antibiotics. Bacillus mycoides and Bacillus subtilis were the most susceptible to the tested extracts. Contrary to this Aspergillus flavus, Aspergillus fumigatus and Penicillium purpurescens were the most resistant. Finally, cytotoxic activity of tested extracts was evaluated on four human cancer cell lines. Extract of E. intestinalis expressed the stronger cytotoxic activity towards all tested cell lines with IC₅₀ values ranging from 74.73 to 155.39 μg/ml.     

Analysis of anti-bacterial and anti oxidative activity of Azadirachta indica bark using various solvents extracts

Herbal medications have been used for relief of symptoms of disease. Regardless of the great advances observed in current medicine in recent decades, plants still make a significant contribution to health care. An alarming increase in bacterial strains resistant to a number of antimicrobial agents demands that a renewed effort be made to seek antibacterial agents effective against pathogenic bacteria resistant to or less sensitive to current antibiotics. Anti-bacterial activity of Azadirachta indica stem bark was tested against pathogenic Salmonella paratyphi and Salmonella typhi using various solvent extracts. The in vitro anti-bacterial activity was performed by agar well diffusion method and the results were expressed as the average diameter of zone of inhibition of bacterial growth around the well. The ethanol and methanol extracts showed better anti-bacterial activity with zone of inhibition (20–25 mm) when compared with other tested extracts and standard antibiotic Erythromycin (15 mcg) with zone of inhibition (13–14 mm). Using Fisher’s exact test of significance difference was found between two Salmonella strains sensitivity patterns against tested extracts (P ⩽ 0.035). Extracts of A. indica stem bark also exhibited significant antioxidant activity, thus establishing the extracts as an antioxidant. The results obtained in this study give some scientific support to the A. indica stem bark for further investigation of compounds and in future could be used as drug.     

Synthesis and evaluation of the antiplasmodial activity of novel indeno[2,1-c]quinoline derivatives

With the aim to explore the potentiality of new chemical scaffolds for the design of new antimalarials, a set of new indeno[2,1-c]quinolines bearing different basic heads has been synthesized and tested in vitro against chloroquine sensitive (CQ-S) and chloroquine resistant (CQ-R) strains of Plasmodium falciparum. Most of the synthesized compounds exhibited a moderate antiplasmodial activity, inhibiting the growth of both CQ-S and CQ-R strains of P. falciparum with IC₅₀ ranging from 0.24 to 6.9 μM and with a very low resistance index. The most potent compounds (1.2–1.3-fold the CQ on the W-2 strain) can be considered as promising ‘lead compounds’ to be further optimized to improve efficacy and selectivity against Plasmodia.     

Volatile Nitrogenous Compounds from Bacteria: Source of Novel Bioactive Compounds

Bacteria can produce nitrogenous compounds via both primary and secondary metabolic processes. Many bacterial volatile nitrogenous compounds produced during the secondary metabolism have been identified and reported for their antioxidant, antibacterial, antifungal, algicidal and antitumor activities. The production of these nitrogenous compounds depends on several factors, including the composition of culture media, growth conditions, and even the organic solvent used for their extraction, thus requiring their identification in specific conditions. In this review, we describe the volatile nitrogenous compounds produced by bacteria especially focusing on their antimicrobial activity. We concentrate on azo-compounds mainly pyrazines and pyrrolo-pyridines reported for their activity against several microorganisms. Whenever significant, extraction and identification methods of these compounds are also mentioned and discussed. To the best of our knowledge, this is first review describing volatile nitrogenous compounds from bacteria focusing on their biological activity.     

Sesquiterpenes from the aerial parts of Artemisia tournefortiana

Sixteen eudesmane-type sesquiterpenes, including six unknown ones (1−6), were isolated from the aerial part of A. tournefortiana. NMR, HERIS-MS, IR spectra and ECD calculation assigned their relative and absolute configurations. Six (6, 7, 9, 13, 15, and 16) were tested for cytotoxic and anti-inflammatory activities, and seven (6, 7, 8, 12, 13, 15, and 16) were tested for antimicrobial activity. Among them, compound 15 showed significant cytotoxicity with IC₅₀ values in the range of 1.49–5.30 μM and moderate antimicrobial activity.     

Comparative assessment of biological activities of different parts of halophytic plant Tamarix articulata (T. articulata) growing in Saudi Arabia

Owing to extremely high salinity and harsh environmental conditions, T. articulata is one of the most abundant wild plants growing in the deserts of Saudi Arabia. Such plants may contain novel compounds to display promising biological activities. Here, in this study, we evaluate the biological activities of methanolic extracts of fresh leaves, dry leaves, stem, and roots of T. articulata. The antioxidant activity was determined by 2, 2-diphenyl-1-picrylhydrazyl (DPPH) and total phenolic and flavonoid content were determined using standard colorimetric methods. Whereas antimicrobial and ant-proliferative activities were determined by standard well-diffusion and 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) methods, respectively. Our results demonstrate that all methanolic extracts of T. articulata showed antioxidant activity, however, the methanolic extract of dry leaves exhibits promising antioxidant effect with IC₅₀ value 49.08 ± 1.98, which was strongly supported by total phenolic (409.92 ± 6.03 mg GAE/g DW) and flavonoid (177.71 mg QE/g DW) content. Although, antimicrobial activity was also exhibited by all the methanolic extracts, however, methanolic extract of dry leaves exhibits promising antimicrobial activity in Gram-positive bacteria Staphylococcus epidemidis. Furthermore, MTT assay revealed that all methanolic extracts exhibit antiproliferative activity in MCF-7 (breast cancer) and RKO (colorectal cancer) cells with IC₅₀ values ranges from 219 ± 5.112 µg/ml to 253 ± 5.231 µg/ml and 220 ± 4.330 µg/ml to 325 ± 6.213 µg/ml, respectively. However, the most promising antiproliferative effect was displayed by methanolic extract of dry leaves with IC₅₀ values 219 ± 5.112 µg/ml and 220 ± 4.330 µg/ml, respectively. In summary, these findings provide evidence that T. articulata has promising biological activities and can be used for many pharmaceutical activities in the future.     

Diversity of natural products of the genera Curvularia and Bipolaris

Covering from 1963 to 2017.This review provides a summary of some secondary metabolites isolated from the genera Curvularia and Bipolaris from 1963 to 2017. The study has a broad objective. First to afford an overview of the structural diversity of these genera, classifying them depending on their chemical classes, highlighting individual examples of chemical structures. Also some information regarding their biological activities are presented. Several of the compounds reported here were isolated exclusively from endophytic and pathogenic strains in culture, while few from other sources such as sea Anemone and fish. Some secondary metabolites of the genus Curvularia and Bipolaris revealed a fascinating biological activities included: anti-malarial, anti-biofouling, anti-larval, anti-inflammatory, anti-oxidant, anti-bacterial, anti-fungal, anti-cancer, leishmanicidal and phytotoxicity. Herein, we presented a bibliography of the researches accomplished on the natural products of Curvularia and Bipolaris, which could help in the future prospecting of novel or new analogues of active metabolites from these two genera.