瑞香狼毒根的抑菌活性成分研究(Ⅱ)

采用生物活性跟踪法 ,首次从瑞香狼毒根中分离出两个具有广谱性杀菌活性的物质 ,通过波谱分析分别鉴定为新狼毒素 B和狼毒色原酮 .生测结果表明 ,两个化合物在 2 2 0 0 m g· L- 1浓度对苹果干腐病菌、小麦赤霉病菌、蕃茄早疫病菌、南瓜枯萎病菌、玉米大斑病菌、烟草赤星病菌和辣椒疫霉病菌均有一定的抑菌作用     

瑞香狼毒根中活性物质的分离鉴定及作用机理

以瑞香狼毒根为研究材料,模式植物拟南芥为受体,采用实验室活体生物实验方法研究了瑞香狼毒根提取物及不同极性溶剂萃取物对7 d龄拟南芥幼苗的生长抑制作用;采用活性跟踪的化合物分离方法,分析了其中的活性化合物成分,并通过拟南芥DR5-GUS转基因株系,研究了单体化合物对拟南芥生长发育及根系生长素分布的影响.结果显示,瑞香狼毒根乙醇提取物对拟南芥有很强的生长抑制作用,其乙酸乙酯和氯仿萃取物的抑制活性最为显著,从氯仿萃取物中分离得到两种香豆素类化合物伞形花内酯(1)和西瑞香素(2),其中化合物1能够显著抑制拟南芥幼苗生长及根系发育,且明显降低了根部内源生长素的分布水平;化合物2也有较为明显的抑制活性.研究表明,氯仿和乙酸乙酯萃取物是瑞香狼毒植物毒活性的主要有效部位;伞形花内酯(1)和西瑞香素(2)是瑞香狼毒植物毒活性的有效成分,化合物1对拟南芥生长发育的抑制作用与生长素途径密切相关.     

瑞香狼毒提取物对试验动物急性毒性及活性的初步研究

采用急性经口、眼刺激、皮肤试验方法,研究了瑞香狼毒乙酸乙酯萃取物的急性毒性作用,同时以番茄晚疫病菌为供试菌,研究了瑞香狼毒提取物的抑菌活性.初步研究表明,瑞香狼毒乙酸乙酯萃取物对小白鼠经口急性毒性为低毒,对白兔的急性皮肤刺激属无刺激性,对白兔的眼刺激属轻度刺激性,对鲫鱼的毒性属于中毒级;瑞香狼毒乙酸乙酯萃取物及其分段物流分B、c、D对番茄晚疫病菌有较好的抑制活性,这为瑞香狼毒乙酸乙酯萃取物进一步开发为产品提供了毒理学依据.     

青藏高原有毒植物瑞香狼毒根抑菌活性初步研究

以人体病原细菌大肠杆菌、金黄色葡萄球菌、深部真菌白色念珠菌、浅部真菌红色毛癣菌、石膏样毛癣菌、石膏样小孢子菌、絮状表皮癣菌为供试菌,采用药敏纸片法对瑞香狼毒活性成分的抑菌活性进行了初步研究。结果表明瑞香狼毒对人体常见病原细菌和真菌有抑制作用,乙酸乙酯萃取物在33．33g／L浓度下对细菌组的抑菌圈直径最高可达12．02mm,对真菌组最高可达9．04mm,并初测瑞香狼毒中的抑菌活性物质主要为中偏强极性成分。     

瑞香狼毒根提取物对山楂叶螨的生物活性

采用不同的生物活性测定方法比较了瑞香狼毒(Stellera chamaejasme L.)根部4种不同溶剂提取物的杀螨活性。结果表明,瑞香狼毒根提取物对山楂叶螨(Tetranychus viennensis Zacher)有很好的触杀和内吸活性。在触杀活性测试中,石油醚提取物和氯仿提取物的杀螨活性最高;在内吸作用中,乙醇、氯仿和石油醚提取物的杀螨活性均较高,杀螨效果显著。在对石油醚提取物的不同溶剂萃取物进行生物活性追踪测定中发现,石油醚萃取物和氯仿萃取物具有较高的生物活性,浓度为0.6 g.L-1,山楂叶螨的24 h校正死亡率分别达到93.22%和79.66%。     

菊苣根提取物的抑菌活性研究

采用离体的试验方法测定了菊苣根的石油醚、乙酸乙酯和乙醇提取物对7种植物病原真菌和3种细菌的抑制活性。采用盆栽试验方法测定了菊苣根提取物对小麦白粉病的防治效果。结果表明,乙醇和乙酸乙酯提取物均有一定的抑制植物病原真菌和细菌活性。且乙酸乙酯提取物效果更佳。在10 g.L-1浓度下,乙酸乙酯提取物能显著抑制小麦赤霉病菌、玉米大斑病菌和烟草赤星病菌3种病原真菌菌丝的生长,抑制率均在85%以上;对小麦根腐病菌、玉米大斑病菌和烟草赤星病菌的孢子萌发抑制率也均在80%以上;对枯草芽孢杆菌和金黄色葡萄球菌的抑菌圈直径达21.01 mm和17.23 mm;对盆栽小麦白粉病的预防和治疗作用分别为50.93%和65.82%。     

高通量测序分析甘肃高寒草原瑞香狼毒根内生菌群落结构特征研究

【背景】瑞香狼毒是我国天然草地退化的标志性植物之一,在入侵的过程中其根内微生物发挥着重要的作用,探究瑞香狼毒根内微生物群落对有益微生物资源的利用及生物防控瑞香狼毒具有重要意义。【目的】探究甘肃省祁连山东麓不同高寒草原毒性杂草瑞香狼毒根部内生真菌和细菌的组成、多样性等群落结构特征。【方法】通过Illumina MiSeq高通量测序技术对甘肃祁连山东麓不同高寒草原的瑞香狼毒根部内生菌组成及多样性进行分析。【结果】不同高寒草原瑞香狼毒根内子囊菌门(Ascomycota)在真菌中占优势地位;蓝细菌(Cyanobacteria)、变形菌门(Proteobacteria)、放线菌门(Actinobacteria)在根内生细菌中属于优势类群。G4样点的真菌和细菌OTU(OperationalTaxonomic Unit)数量和Shannon多样性指数均高于其他4个采样点。主坐标分析(Principal Coordinate Analysis,PCoA)表明,不同高寒草原瑞香狼毒根内生菌群落之间存在一定的差异。One-Way ANOVA分析结合Pearson相关性分析显示,不同样地瑞香狼毒真菌群落结构在属水平上相关性较小,而细菌在属水平存在一定的相关性。【结论】本研究为进一步开发利用瑞香狼毒内生真菌和细菌资源、阐明瑞香狼毒内生菌群的群落结构和生态功能提供理论参考。     

瑞香狼毒根中异新狼毒素A和新狼毒素B对松材线虫和拟松材线虫的触杀活性研究

从瑞香狼毒(Stellera chamaejasme L.)根乙醇提取物中分离得到了两个二氢黄酮类化合物,结合核磁共振波谱学数据解析,确定其结构为异新狼毒素A(isoneochamaejasmin A)和新狼毒素B(neochamaejasmin B)。并采用实验室活体生物试验方法,研究了这两个化合物对松材线虫(Bursaphelenchus xylophilus)和拟松材线虫(Bursaphelenchus mucronatus)二龄幼虫的触杀活性。结果表明,异新狼毒素A和新狼毒素B对两种线虫均具有一定的触杀活性,且在相同的处理时间和浓度下,新狼毒素B对两种线虫的触杀活性均强于异新狼毒素A。     

家蝇共生真菌的抗菌活性筛选及菌株CY-03的初步鉴定

利用平板分离法从家蝇中分离出14株家蝇共生真菌,活性筛选表明CY-03有较好的抗菌活性,在供试浓度为0.1 mg/m L时,CY-03发酵液乙酸乙酯萃取物对番茄早疫病菌和苹果树腐烂病菌具有较好的抑制作用,抑制率约60%;在供试浓度为30μg/滤纸片时,与阳性对照相比,乙酸乙酯提取物对枯草芽胞杆菌有中等的抑制作用,抑菌圈直径为21.0 mm。进一步研究CY-03发酵液不同极性溶剂萃取物的抗菌活性,结果表明其活性物质主要集中在中等极性部位,在供试浓度为0.1 mg/m L时,CY-03发酵液乙酸乙酯提取物对苹果树腐烂病菌、杨树溃疡病菌、番茄早疫病菌和苦瓜枯萎病菌等具有较好的抑制作用,抑制率均大于45%;在供试浓度为30μg/滤纸片时,乙酸乙酯提取物对金黄色葡萄球菌、枯草杆菌和大肠埃希菌有中等的抑制作用,抑菌圈直径范围为14.8~23.0 mm。通过形态学特征观察和5.8S r DNA测序分析,初步确定该菌株为尖孢镰刀菌(Fusarium oxysporum)。CY-03作为微生物源杀菌剂值得进一步研究。     

瑞香狼毒根部烷烃类提取物GC-MS分析及抑瘤活性初探

通过正己烷提取瑞香狼毒根部成分,采用气相色谱-质谱联用技术对瑞香狼毒根部烷烃类提取物(SRH)的成分进行分析,同时考察SRH对H22皮下荷瘤小鼠的抑瘤作用。结果表明:通过GC-MS分析,SRH共分离得到55个组分,结构确定的有44个,占总峰面积的97.73%,其中烃类化合物11个,芳香族化合物10个,酸类化合物有9个,酯类化合物有7个,醇类化合物有4个,其他类型化合物有3个。其中含量在1%以上的物质有(Z,Z)-9,12-十八烷二烯酸,邻苯二甲酸-2-乙基己酯,9,17-十八烷二烯,反式角鲨烯,γ-谷甾醇,邻苯二甲酸二丁酯,n-十六酸,硬脂酸,二十酸,菜油甾醇,占总峰面积90.74%,检测出的角鲨烯,亚油酸,菜油甾醇都具有一定的抗肿瘤活性,在瑞香狼毒抗肿瘤方面的研究未见报道;同时SRH在实验前期对肿瘤的生长起到了很好的抑制作用,尤其是SRH低剂量,其抑制率达到21.5%。该结果为瑞香狼毒根部成分的物质分析及抑瘤应用前景提供了一定的理论依据。     

Antifungal activity of biflavones from Taxus baccata and Ginkgo biloba

Bilobetin and 4'-O-methylamentoflavone were isolated and identified in the needles of Taxus baccata, for the first time in this species. The antifungal activity of biflavones from T. baccata and Ginkgo biloba, namely amentoflavone, 7-O-methylamentoflavone, bilobetin, ginkgetin, sciadopitysin and 2,3-dihydrosciadopitysin towards the fungi Alternaria alternata, Fusarium culmorum, Cladosporium oxysporum was determined employing computer-aided image analysis couplet to a microscope. Bilobetin exhibited a significant antifungal activity with values of ED50 14, 11 and 17 microM respectively. This compound completely inhibited the growth of germinating tubes of Cladosporium oxysporum and Fusarium culmorum at a concentration 100 microM. Activity of ginkgetin and 7-O-methylamentoflavone towards Alternaria alternata was stronger than that of bilobetin. Moreover, slight structural changes in the cell wall of Alternaria alternata exposed to ginkgetin at concentration of 200 microM were observed.     

欧美107杨树提取物体外对植物病原真菌的抑制活性

制备了欧美107杨树枝条和叶的乙醇粗提物及不同极性溶剂的萃取部分,并测定了它们对植物病原真菌的抑制活性。枝条和叶的乙醇粗提物对棉花枯萎病菌、小麦纹枯病菌、番茄早疫病菌、番茄枯萎病菌、黄瓜枯萎病菌、小麦赤霉以及玉米弯孢等7种植物病原真菌均具有一定的抑制作用。而枝条的乙醇粗提物对杨树溃疡病菌的菌丝生长有一定的促进作用。抗菌活性成分主要集中在乙酸乙酯萃取部分。     

侧柏乙醇提取物对21种植物病原真菌的抑菌活性

采用菌丝生长速率法测定了侧柏(Platycladus orientalis)叶、小枝、球果和种子4个不同部位乙醇提取物对21种植物病原真菌的抑菌活性。结果显示:(1)在供试浓度为50g/L(相当于干样)时,侧柏各部位乙醇提取物对4种供试植物病原真菌均具有较好抑制作用,其中侧柏叶提取物的抑菌效果最好,对供试葡萄白腐病菌(Conio-thyrium diplodiella)、葡萄黑痘病菌(Elsinoe ampelina)、番茄绵腐病菌(Phytophthora melongenae)和青霉病菌(Penicilliu mexpansum)的EC50分别为:5.424、3.186、8.913和19.000g/L。(2)侧柏叶乙醇提取物的石油醚萃取物和乙酸乙酯萃取物抑菌活性均较好,在供试浓度为0.5g/L时,石油醚萃取物对苹果腐烂病菌(Valsa mali)和葡萄黑痘病菌(E.ampelina)的抑菌率分别为80.35%和60.23%;乙酸乙酯萃取物对以上2种植物病原菌的抑菌率分别为81.88%和64.06%。结果表明:侧柏叶、小枝、球果和种子乙醇提取物均具有一定抑菌活性,叶乙醇提取物的活性最好,活性成分主要集中在石油醚萃取物和乙酸乙酯萃取物中。     

Screening and characterization of endophytic fungi of Panax ginseng Meyer for biocontrol activity against ginseng pathogens

Forty endophytic fungi isolated from ginseng plants were screened to identify metabolites that had antifungal activity against ginseng microbial pathogens. The metabolites from the fungi were extracted from the liquid culture filtrates using ethyl acetate and then evaluated in vitro for antimicrobial activity against ginseng pathogens (Alternaria panax, Botrytis cinerea, Colletotrichum panacicola, Cylindrocarpon destructans, Rhizoctonia solani, and Phytophthora cactorum). Six of the fungi (Colletotrichum pisi, Fusarium oxysporum, Fusarium solani, Phoma terrestris, unknown 1 and 2) showed effective antimicrobial activity against all or some of the ginseng pathogens, with the extract of P. terrestris showing the strongest antimicrobial activity. The extract also showed inhibitory activity against spore germination of the pathogens. Gas chromatography–mass spectrometry (GC–MS) analysis of P. terrestris extract revealed that forty-one compounds were present in metabolites containing mainly N-amino-3-hydroxy-6-methoxyphthalimide (32% of the total metabolites) and 5H-dibenz [B, F] azepine (7%). Treatment with P. terrestris extract also caused morphological changes and reduced expression of the genes involved in mycelial growth and virulence. Treatment also induced defense-related genes in detached Arabidopsis leaves that were inoculated with the pathogens. These results indicate the antimicrobial potential for use of metabolites extracted from the ginseng endophytic fungi as alternatives to chemicals for biocontrol.     

菊芋叶片提取物抑菌活性与化学成分的研究

为了开发新型植物源杀菌剂和充分利用菊芋(Helianthus tuberosus L.)资源,本文尝试用石油醚、乙醚、乙酸乙酯和水等4种溶剂对菊芋叶片进行平行提取,采用生长速率法测定菊芋叶片提取物对水稻纹枯菌(Rhizoc-tonia solaniKühn)、小麦赤霉菌[Gibberella zeae(Schw.)Petch]、番茄早疫菌[Alternaria solani(Ellis et Martin)Jones et Grour]和番茄灰霉菌(Botrytis cinerea Pers.)生长量的抑制活性;并通过试管法和滤纸法对菊芋叶片内化学成分进行初步预试。抑菌实验结果表明:(1)菊芋叶片各溶剂提取物处理与对照处理相比差异显著;(2)菊芋叶片水提取物处理与各有机溶剂提取物处理差异也基本显著;(3)菊芋叶片各溶剂提取物同浓度处理对水稻纹枯菌、番茄早疫菌和番茄灰霉菌抑制效果较好;(4)菊芋叶片乙酸乙酯提取物抑菌效果最为显著,浓度为20mg/mL时对番茄早疫菌和番茄灰霉菌已达到完全抑制,对水稻纹枯菌抑制率也达到77.91%。初步化学预试结果说明,菊芋叶片中含有蛋白质、氨基酸、还原糖类、有机酸、酚类和鞣质、黄酮类、内酯类、强心甙以及油脂等化学成分。     

Antibacterial and antifungal activities of andrachne cordifolia muell

The crude methanolic extract of Andrachne cordifolia Muell. (Euphorbiaceae) and its various fractions in different solvent systems (chloroform, ethyl acetate and n- butanol) were screened for antibacterial and antifungal activities. Crude extract and subsequent fractions demonstrated moderate to excellent antibacterial activities against the tested pathogens. Highest antibacterial activity was displayed by both chloroform and ethyl acetate fractions (100%) followed by the crude extract (68%) against Salmonella typhi. Similarly, crude extract and its subsequent fractions showed mild to excellent activities in antifungal bioassay with maximum (76%) antifungal activity against Microsporum canis by the chloroform fraction followed by the crude extract (65%).     

Antifungal activity of extracts of the lichens Parmelia reticulata,Ramalina roesleri,Usnea longissima and Stereocaulon himalayense

Antifungal activity of the hexane, dichloromethane, ethyl acetate, methanol and aqueous extracts of the lichens namely, Parmelia reticulata, Ramalina roesleri, Usnea longissima and Stereocaulon himalayense were evaluated against nine soil-borne pathogenic fungi namely Rhizoctonia bataticola, Sclerotium rolfsii, Alternaria alternata, Pythium debaryanum, Fusarium oxysporum, Rhizoctonia solani, Botrytis cinerea, Sclerotina sclerotium and Pythium aphanidermatum by food poison technique. ED₅₀ (Effective dose for 50% of inhibition) was calculated using Probit analysis. Hexane and dichloromethane extracts from all the four lichen species were found most active against the test fungi while aqueous extract was found to be least effective against all the test pathogenic fungi. The highest inhibition was recorded with hexane extracts of P. reticulata, R. roesleri, U.longissima and S. himalayense against R. bataticola with ED₅₀ 25.1, 24.50, 18.91 and 51.36 μg ml^?1, respectively.     

Antibacterial and antifungal activities of andrachne cordifolia muell

The crude methanolic extract of Andrachne cordifolia Muell. (Euphorbiaceae) and its various fractions in different solvent systems (chloroform, ethyl acetate and n-butanol) were screened for antibacterial and antifungal activities. Crude extract and subsequent fractions demonstrated moderate to excellent antibacterial activities against the tested pathogens. Highest antibacterial activity was displayed by both chloroform and ethyl acetate fractions (100%) followed by the crude extract (68%) against Salmonella typhi. Similarly, crude extract and its subsequent fractions showed mild to excellent activities in antifungal bioassay with maximum (76%) antifungal activity against Microsporum canis by the chloroform fraction followed by the crude extract (65%).     

Chemical composition and fungitoxic activity of essential oil of Thuja orientalis L. grown in the north-western Himalaya

The essential oil from fresh leaves of Thuja orientalis L. grown in the north-western Himalaya was isolated by means of hydrodistillation and analyzed by GC and GC/MS. Twenty-two compounds representing 94.0% of the total oil were identified. The leaf oil contained alpha-pinene (29.2%), Delta-3-carene (20.1%), alpha-cedrol (9.8%), caryophyllene (7.5%), alpha-humulene (5.6%), limonene (5.4%), alpha-terpinolene (3.8%) and alpha-terpinyl acetate (3.5%) as major constituents. The essential oil showed antifungal activity against Alternaria alternata in a direct bioautography assay. Two main bioactive compounds named as b1 (Rf = 0.54) and b2 (Rf = 0.80) were observed and tested for antifungal activity; they produced an inhibition zone of 5 and 10 mm in diameter, respectively. The components b1 and b2 were further purified by preparative thin layer chromatography and their antifungal efficacy was re-tested. The minimum inhibitory amount (MIA) of b1 and b2 against A. alternata was determined as 30.5 and 4.5 microg, respectively, using a bioautography assay. The bioactive constituent corresponding to b1 was determined as alpha-cedrol by using GC/MS analysis. The potential of essential oils as a source of natural biocides is discussed.     

Antifungal activity in vitro of Baccharis glutinosa and Ambrosia confertiflora extracts on Aspergillus flavus, Aspergillus parasiticus and Fusarium verticillioides

The aims of this study were to evaluate the antifungal properties of Baccharis glutinosa and Ambrosia confertiflora extracts against Aspergillus flavus, A. parasiticus and Fusarium verticillioides, and to isolate the group of compounds that are responsible for the antifungal activity. Samples of aerial parts from each plant were extracted with 70% methanol and sequentially partitioned with hexane, ethyl acetate, and n-butanol. The partitioned fractions were evaluated in their capacity to inhibit the radial growth of the three species of fungi. The active fraction was used for an assay-guided chromatography of antifungal extracts. The results showed that the extract from B. glutinosa partitioned in ethyl acetate (Bea) showed the highest antifungal activity against the three fungi. Bea completely inhibited the growth of F. verticillioides at 0.8 mg/ml, whereas the radial growth of A. flavus and A. parasiticus was inhibited 70% at 1.5 mg/ml. The purified antifungal fraction from Bea showed 72, 54, and 52% of antifungal activity, respectively.