肉桂醛、柠檬醛对烟曲霉色素及关键基因alb1mRNA表达的影响

研究了肉桂醛、柠檬醛对烟曲霉色素及其关键基因alb1 mRNA表达的影响。结果表明随着肉桂醛、柠檬醛浓度的增加,菌苔逐渐变稀、薄且烟绿色色素逐渐变淡,甚至白化;肉桂醛、柠檬醛对alb1基因mRNA表达有明显抑制作用,随着药物浓度的降低这种抑制作用亦相应呈现不同程度的减弱,肉桂醛、柠檬醛可能通过抑制alb1 mRNA的表达导致烟曲霉缺失烟绿色色素。     

微量液基稀释法测定中药活性成分的体外抗曲霉菌活性*

通过测定中药活性成分肉桂醛和柠檬醛对常见深部条件致病性真菌黄曲霉、烟曲霉的抗菌活性,为建立中药抗曲霉菌药敏试验标准提供参考依据。参照美国国家临床试验标准化委员会(National Committee for Clinical Laboratory Standards,NCCLS)提出的标准,用微量液基稀释法分别测定肉桂醛和柠檬醛对黄曲霉、烟曲霉的抗菌活性。肉桂醛对黄曲霉、烟曲霉最低抑菌浓度(Minimal inhibitory concentration,MIC)分别为：0.100μg/mL,0.050μg/mL,柠檬醛对黄曲霉、烟曲霉的MIC分别为：2．600μg/mL、0．650μg/mL。中药活性成分肉桂醛和柠檬醛具有高效抗曲霉作用。该研究可为制定中药抗曲霉作用评价标准提供参考依据。     

植物精油对金针菇保鲜效果的研究

为开发天然绿色的食用菌专用型保鲜剂,对4种植物精油抑制黑曲霉(Aspergillus niger)、产黄青霉(Penicillium chrysogenum)、绿色木霉(Trichoderma viride)和木霉(Trichoderma sp.)等病原真菌的效果进行分析,并以金针菇为材料进行初步保鲜效果评价。研究结果显示,薰衣草精油对黑曲霉的抑制率最高,为17.86%,柠檬醛对产黄青霉及木霉的抑制率最高,分别为16.69%和34.41%,而茴香油则对绿色木霉的抑制率最高,达17.39%。经柠檬醛处理的金针菇在保鲜过程中,失重率、褐变度被显著抑制,还原糖含量增加,CAT活性降低的趋势被减缓。这些指标均显示柠檬醛具有较好的保鲜效果,是开发天然绿色保鲜剂的良好材料。     

肉桂醛对阿萨希毛孢子菌临床分离株的生长及其生物膜形成的影响

目的研究中药单体肉桂醛是否对阿萨希毛孢子菌的生长及其生物膜形成有影响。方法选取临床分离菌株进行ITS基因序列分析及VITEK MS鉴定,通过培养建立体外生物膜模型。倍比稀释法测定1050 mg/L、525 mg/L、262.5 mg/L和131.25 mg/L浓度肉桂醛溶液对阿萨希毛孢子菌生长的抑制作用,银染法观察不同浓度肉桂醛对阿萨希毛孢子菌生物膜形成的影响。结果实验中各浓度的肉桂醛都能抑制阿萨希毛孢子菌的生长,延长生物膜的形成时间,且肉桂醛浓度越高,其作用效果越明显。当肉桂醛浓度达到1050 mg/L时,对阿萨希毛孢子菌生长的抑制效果最显著,该浓度下培养基孔内未见阿萨希毛孢子菌生长。银染法观察可见,此浓度下培养基内未形成生物膜,表明1050 mg/L浓度肉桂醛对阿萨希毛孢子菌生物膜的形成产生了明显的抑制作用。结论肉桂醛能够抑制阿萨希毛孢子菌生长及其生物膜形成。     

植物精油对大菱鲆弧菌的体外和体内抗菌活性

【目的】研究天然植物精油对大菱鲆弧菌的体外和体内抗菌活性。【方法】采用纸片扩散法和微量肉汤稀释法对14种植物精油或其组分的体外抑菌活性进行检测;通过细菌形态透射电镜观察、胞内乳酸脱氢酶及核酸释放研究山苍子精油对大菱鲆弧菌的膜损伤作用;采用大菱鲆人工攻毒感染实验研究山苍子精油的体内抗菌作用。【结果】14种植物精油或其组分对大菱鲆弧菌具有不同程度的抑制效果,其中肉桂醛的抗菌活性最强,最低抑菌浓度为0.25μL/m L;百里香酚、丁香酚、柠檬醛和山苍子的抗菌活性次之,最低抑菌浓度为0.5μL/m L;山苍子精油可破坏大菱鲆弧菌的细胞膜,并导致胞内蛋白酶和核酸外泄;经200μL/L山苍子精油浸浴后,大菱鲆攻毒后死亡率由对照组50%降至0。【结论】富含芳香醛、芳香酚和柠檬醛的植物精油对大菱鲆弧菌具有良好抗菌活性,有望替代抗生素用于大菱鲆弧菌病的防治。     

柠檬醛熏蒸对互隔交链孢生长及其产毒的抑制作用

互隔交链孢是一种重要的能产生交链孢酚（AOH）等真菌毒素的植物病原菌。精油是重要的抑制病原菌侵染的挥发性植物提取物,其活性组分包括柠檬醛等。本研究表明柠檬醛可高效地抑制互隔交链孢的生长和AOH毒素的产生。柠檬醛熏蒸能够引起互隔交链孢菌丝断裂影响其延伸,而对其分生孢子结构的影响不明显。柠檬醛能够引起互隔交链孢活性氧生成的紊乱,这可能是导致AOH显著下降的原因之一。由于柠檬醛能高效抑制互隔交链孢生长和产毒,因此其可作为传统熏蒸剂的潜在替代品,以防控互隔交链孢引起的病害以及毒素污染。柠檬醛抑制互隔交链孢生长产毒的研究为其开发与应用奠定了良好的基础。     

天然抗菌剂对5种致病菌的抑制作用研究

目的研究天然抗菌剂对金黄色葡萄球菌、大肠杆菌、绿脓杆菌、白念珠菌和黑曲霉的抑制作用。方法采用杯碟法和微孔板法测定天然抗菌剂对5种致病菌的抑菌圈大小、最小抑菌浓度(MIC)及对10株金黄色葡萄球菌的MIC。结果 1%天然抑菌剂对金黄色葡萄球菌、大肠杆菌、绿脓杆菌、白念珠菌和黑曲霉的抑菌圈分别是14.47 mm、10.67 mm、9.13 mm、28.13 mm、10.53 mm;天然抑菌剂对金黄色葡萄球菌、大肠杆菌、绿脓杆菌、白念珠菌和黑曲霉的MIC分别是0.08%、0.16%、0.63%、0.08%、0.16%,阳性对照(Sensiva SC50)对这5种菌的MIC分别是0.16%、0.16%、0.31%、0.16%、0.13%;天然抗菌的对10株金黄色葡萄球菌的MIC值分别为0.08%、0.06%、0.05%、0.09%、0.06%、0.07%、0.10%、0.06%、0.09%、0.07%。结论天然抗菌剂对这5种菌均有一定的抑制作用,对金黄色葡萄球菌和白念珠菌的抑制效果优于阳性对照,对大肠杆菌和黑曲霉的抑制效果与阳性药相当,对绿脓杆菌的效果略差于阳性药,对10株金黄色葡萄球菌均有较好的抑制作用。     

柠檬醛对杨梅采后保鲜的作用研究

杨梅(Myrica rubra Sieb.Zucc.)是一种富含抗氧化物的健康水果,但极易腐烂变质,应用生物保鲜剂对杨梅保鲜具有无毒、经济和易推广等优点。本研究从自然腐烂的杨梅中分离纯化出7种腐烂病原菌菌株,其中Penicillium georgiense首次在杨梅采后病腐中被报道;在此基础上研究了柠檬醛对杨梅采后保鲜效果和对4种主要杨梅腐烂病原菌的抑菌机理。结果表明:用1.00%(体积分数)柠檬醛对杨梅进行熏蒸处理,可显著提高冷贮条件下杨梅的好果率;柠檬醛抑菌动力学研究表明0.10%(体积分数)柠檬醛可有效抑制4种病原菌孢子形成,从而抑制病原菌生长繁殖,以降低杨梅腐烂率。柠檬醛是一种有效的杨梅抑菌保鲜剂,它的应用将有利于杨梅采后保鲜,并可促进这一果树资源的开发利用。     

三种山苍子精油化学成分及抑菌效果差异分析

为探究山苍子不同种之间化学成分及抑菌效果的差异,本研究通过生长速率法和抑菌圈法测定三种山苍子精油对尖孢镰刀菌、大肠杆菌和李斯特菌的抑菌活性,同时对三种山苍子精油进行GC-MS挥发性成分鉴定,进一步对精油主要化学成分与抑菌率进行相关性分析。结果表明,山鸡椒果实精油含量最高且对尖孢镰刀菌、大肠杆菌和李斯特菌的抑菌效果优于毛叶木姜子和毛山鸡椒;三种山苍子精油抑菌效率均与柠檬醛、芳樟醇的含量分别呈现显著正相关,提示主要成分柠檬醛含量适合作为山苍子优良精油筛选的可靠指标。研究结果为山苍子精油抗菌物质的开发利用提供了理论依据。     

桂皮醛衍生物的合成及其对CVB_3的作用

目的：合成桂皮醛衍生物,观测其对心肌细胞的毒性及抗CVB3病毒的作用。方法：化学合成6种桂皮醛衍生物,其中3种进行了红外、质谱等结构表征;MTT法检测被CVB3病毒感染和用桂皮醛衍生物治疗后的心肌细胞活性。结果：α-溴代对氯肉桂醛、α-溴代对甲基肉桂醛、对氯肉桂醛3种桂皮醛衍生物对心肌细胞的半数毒性浓度（TC50）分别为2151.28μg·mL-1,1475.32μg·mL-1,22460.32μg·mL-1;对CVB3病毒的半数抑制浓度（IC50）分别为178.94μg·mL-1、173.35μg·mL-1、6045.25μg·mL-1;对CVB3病毒的治疗指数（TI）分别为12.02,8.51,3.71。结论：桂皮醛3种衍生物具有直接抑制CVB3病毒作用,但对病毒的细胞合成和吸附无明显作用。     

In vitro antifungal, anti-elastase and anti-keratinase activity of essential oils of Cinnamomum-, Syzygium- and Cymbopogon-species against Aspergillus fumigatus and Trichophyton rubrum

This study was aimed to evaluate effects of certain essential oils namely Cinnamomum verum, Syzygium aromaticum, Cymbopogon citratus, Cymbopogon martini and their major components cinnamaldehyde, eugenol, citral and geraniol respectively, on growth, hyphal ultrastructure and virulence factors of Aspergillus fumigatus and Trichophyton rubrum. The antifungal activity of essential oils and their major constituents was in the order of cinnamaldehyde>eugenol>geraniol=C. verum>citral>S. aromaticum>C. citratus>C. martini, both in liquid and solid media against T. rubrum and A. fumigatus. Based on promising antifungal activity of eugenol and cinnamaldehyde, these oils were further tested for their inhibitory activity against ungerminated and germinated conidia in test fungi. Cinnamaldehyde was found to be more active than eugenol. To assess the possible mode of action of cinnamaldehyde, electron microscopic studies were conducted. The observations revealed multiple sites of action of cinnamaldehyde mainly on cell membranes and endomembranous structures of the fungal cell. Further, test oils were also tested for their anti-virulence activity. More than 70% reduction in elastase activity was recorded in A. fumigatus by the oils of C. verum, C. martini, eugenol, cinnamaldehyde and geraniol. Similar reduction in keratinase activity in A. niger was recorded for the oils of C. martini and geraniol. Maximum reduction (96.56%) in elastase activity was produced by cinnamaldehyde whereas; geraniol caused maximum inhibition (97.31%) of keratinase activity. Our findings highlight anti-elastase and anti-keratinase activity of above mentioned essential oils as a novel property to be exploited in controlling invasive and superficial mycoses.     

石花菜和海蒿子提取物抗菌活性初步研究

采用圆形纸片法,对石花菜和海蒿子粗提取物及萃取得到的不同极性组分进行抗菌实验。结果表明,石花菜和海蒿子均有不同程度的抗菌作用,海蒿子粗取物的抗细菌活性强于抗真菌活性,而石花菜乙醇提取物抗黑曲霉活性大于抗大肠杆菌、金黄色葡萄球菌以及枯草杆菌活性,其抑菌圈可达4 mm。     

Rare trisubstituted sesquiterpenes daucanes from the wild Daucus carota

Phytochemical and biological investigation of the roots of the wild Daucus carota ssp. carota afforded three new and four known compounds, including four sesquiterpenes daucane esters (1-3 [new], and 4), one polyacetylene (5), one sesquiterpene coumarin (6), and sitosterol glucoside. The structures of the new compounds were determined by comprehensive NMR studies, including DEPT, COSY, NOESY, HMQC and HMBC analyses. Based on an agar diffusion assay, 1, 2 and 4-6 were screened and found to contain a range of low antibacterial activities against four gram positive (Staphylococcus aureus, Streptomyces scabies, Bacillus subtilus, Bacillus cereus) and two gram negative species (Pseudomonas aeruginosa, Escherichia coli) as well as antifungal against Fusarium oxysporum and Aspergillus niger using cup agar diffusion assay.     

Biotransformation of geraniol, nerol and citral by sporulated surface cultures of Aspergillus niger and Penicillium sp

The biotransformation of geraniol, nerol and citral by Aspergillus niger was studied. A comparison was made between submerged liquid, sporulated surface cultures and spore suspensions. This bioconversion was also carried out with surface cultures of Penicillium sp. The main bioconversion products obtained from geraniol and nerol by liquid cultures of A. niger were linalool and alpha-terpineol. Linalool, alpha-terpineol and limonene were the main products obtained from nerol and citral by sporulated surface cultures, whereas geraniol was converted predominantly to linalool, also resulting in higher yields. Bioconversion of nerol with Penicillium chrysogenum yielded mainly alpha-terpineol and some unidentified compounds. With P. rugulosum the major bioconversion product from nerol and citral was linalool. The bioconversion of nerol to alpha-terpineol and linalool by spore suspensions of A. niger was also investigated. Finally the biotransformation with sporulated surface cultures was also monitored by solid phase microextraction (SPME). It was found that SPME is a very fast and efficient screening technique for biotransformation experiments.     

柠檬醛顺反异构体对黄曲霉超微结构及膜功能的影响

研究柠檬醛顺反异构体（香叶醛和橙花醛）抗菌性是阐明该醛抗菌机理核心所在.用酶转化法合成香叶醛和橙花醛后,用液态或气态的异构单体分别对黄曲霉孢子及菌丝体进行毒化.采用透射电镜、多维显微及激光拉曼散射技术对毒化的黄曲霉孢子及菌丝体进行显微结构观察和膜相关参数的测定.结果表明,无论是液体还是气体毒化方式,柠檬醛顺反异构体单独存在时均有抗黄曲霉作用;二者混合物的抗菌总活性与单体相比表现出一定程度协同性;二个异构单体的抗菌作用不仅表现为破坏黄曲霉超微结构,而且还反映在损伤其细胞膜体积调节功能及变形能力.     

Inhibitory Effect of Essential Oils on Aspergillus ochraceus Growth and Ochratoxin A Production

Ochratoxin A (OTA) is a mycotoxin which is a common contaminant in grains during storage. Aspergillus ochraceus is the most common producer of OTA. Essential oils play a crucial role as a biocontrol in the reduction of fungal contamination. Essential oils namely natural cinnamaldehyde, cinnamon oil, synthetic cinnamaldehyde, Litsea citrate oil, citral, eugenol, peppermint, eucalyptus, anise and camphor oils, were tested for their efficacy against A. ochraceus growth and OTA production by fumigation and contact assays. Natural cinnamaldehyde proved to be the most effective against A. ochraceus when compared to other oils. Complete fungal growth inhibition was obtained at 150–250 µL/L with fumigation and 250–500 µL/L with contact assays for cinnamon oil, natural and synthetic cinnamaldehyde, L. citrate oil and citral. Essential oils had an impact on the ergosterol biosynthesis and OTA production. Complete inhibition of ergosterol biosynthesis was observed at ≥100 µg/mL of natural cinnamaldehyde and at 200 µg/mL of citral, but total inhibition was not observed at 200 µg/mL of eugenol. But, citral and eugenol could inhibit the OTA production at ≥75 µg/mL and ≥150 µg/mL respectively, while natural cinnamaldehyde couldn’t fully inhibit OTA production at ≤200 µg/mL. The inhibition of OTA by natural cinnamaldehyde is mainly due to the reduction in fungal biomass. However, citral and eugenol could significant inhibit the OTA biosynthetic pathway. Also, we observed that cinnamaldehyde was converted to cinnamic alcohol by A. ochraceus, suggesting that the antimicrobial activity of cinnamaldehyde was mainly attributed to its carbonyl aldehyde group. The study concludes that natural cinnamaldehyde, citral and eugenol could be potential biocontrol agents against OTA contamination in storage grains.     

内生黑曲霉JS-1对稻瘟病的拮抗作用研究

利用平板对峙法和牛津杯法,从疏花水柏枝、金银花、秋华柳的内生菌中,筛选出1株对稻瘟病菌具有很强抑制作用的菌株JS-1。经生理生化实验和18S rDNAITS序列分析,确定该菌株为黑曲霉(Aspergillus niger)。实验结果表明,JS-1发酵液作用稻瘟病菌后,稻瘟病菌的菌丝变细,分支减少,菌丝基质颜色变浅,作用72 h后干重显著降低。进一步实验表明,该菌产生的活性物质位于其发酵液的乙酸乙酯酯相部位,对稻瘟病病菌抑制率高达96.1%。大田实验数据（天然接种圃）显示,添加该物质后,丰两优4号（中感）和广陆矮4号（易感）叶瘟病情指数分别只有16.25%和32.48%,对稻瘟病的防治取得了很好的效果,说明该菌株具有开发成高效生物农药的巨大潜能。     

华南十大功劳提取物抑菌活性初步研究

以超声提取和索氏提取方法,比较华南十大功劳叶和茎提取物经不同溶剂和不同极性萃取物萃取的抑菌活性大小。结果表明,叶和茎均含有抑菌活性物质,而叶的抑菌效果更强;索氏提取物与超声提取抑菌效果差异不大;华南十大功劳提取物对金黄色葡萄球菌、大肠杆菌、枯草杆菌、藤黄球菌、白色念珠菌的最低抑菌浓度分别为0.6 g/mL、1.0 g/mL、0.8 g/mL、1.0 g/mL、2.0 g/mL;其最小杀菌浓度均为2.0 g/mL,但其对黑曲霉没有抑制作用;不同溶剂提取物中,无水甲醇溶液提取物具有最佳抑菌效果。提取物易溶解于极性萃取物。5种敏感菌对华南十大功劳提取物的敏感性由强到弱依次为：金黄色葡萄球菌菌＞枯草杆菌＞藤黄球菌＞大肠杆菌＞白色念珠菌。     

Antifungal action and antiaflatoxigenic properties of some essential oil constituents

The effect of 20 essential oil constituents on Aspergillus flavus growth and aflatoxin production was tested at the level of 1000 ppm. Some of the tested oils exhibited inhibitory effects on fungal growth and toxin formation. Five oils, namely geraniol, nerol and citronellol (aliphatic oils), cinnamaldehyde (aromatic aldehyde) and thymol (phenolic ketone), completely suppressed growth and aflatoxin synthesis. Trials for determining the minimum inhibitory concentration (MIC) of these oils revealed that geraniol, nerol and citronellol were effective at 500 ppm, while thymol and cinnamaldehyde were highly effective at doses as low as 250 and 200 ppm, respectively. It was observed that citral, citronellal and eugenol prevented fungal growth and toxin formation for up to 8 d. However, after 15 d of incubation, toxin production was greater than the controls.     

Synthesis and evaluation of demethoxyviridin derivatives as potential antimicrobials

The in vitro antibacterial and antifungal activities of demethoxyviridin and some synthetic analogues were evaluated by the agar diffusion method. The minimum inhibitory concentrations (MIC) of the active compounds were also determined by the agar dilution method. Demethoxyviridin (1) showed moderate antibacterial activity against most of the strains tested. 1alpha-Hydroxydemethoxyviridin (3) showed antibacterial activity and the most potent in vitro antifungal activity with MIC of 20 microg/ml (0.062 mM) against Aspergillus niger, A. fumigatus, A. flavus, A. parasiticus, Fusarium solani, F. graminarum, Geotrichum candidum whereas 5'-methylfuro-(4',3',2'-4,5,6)androst-5-ene-3,17-dione (7) exhibited very weak antifungal activity against Candida albicans only.