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摘要： 目的:研究内生真菌皮壳青霉Penicillium crustosum固体发酵产物的化学成分。方法:利用硅胶、Sephadex LH-20葡聚糖凝胶、高效液相色谱等多种色谱分离技术对皮壳青霉固体发酵产物的乙酸乙酯部位进行分离,通过NMR和ESI-MS鉴定化合物结构,通过二倍稀释法和CCK-8法对化合物进行抑菌及抗肿瘤活性测试。结果:从皮壳青霉发酵产物中分离纯化得到12个化合物,分别鉴定为:2′,4′-dihydroxy-3′,5′-dimethyl acetophenone(1)、4-methyl-6-acetylresorcinol(2)、methyl-2,4-dihydroxy-3,5,6-trimethylbenzoate(3)、communol F(4)、communol E(5)、6-acetyl-2α,5-dihydroxy-2-(2-hydroxypropyl)-3α,8-dimethylchroman(6)、butyl isobutyl phthalate(7)、ethyl ferulate(8)、7βhydroxygeosmin(9)、3-hydroxy-4-phenylquinolin-2(1H)-one(10)、(Z)-3-benzylidene-4-methyl-3,4-dihydro-1H-benzo[e][1,4]diazepine-2,5-dione(11)、(3S)-1,4-benzodiazepine-2,5-diones(12)。化合物的MIC值均大于100μg/mL,IC50值均大于100μmol/L。结论:其中,化合物2、4、5、7~9为首次从皮壳青霉中分离得到。所有化合物均未表现出明显的抑菌或抗肿瘤活性。
关键词: 皮壳青霉 ；内生真菌 ；化学成分 ；生物活性
摘要： 为建立气相–质谱联用技术(GC-MS)分析柳杉叶挥发油成分,并研究柳杉叶挥发油的抗菌活性。本研究以柳杉叶为材料,采用水蒸汽蒸馏法提取柳杉叶挥发油;以三种常见细菌和一种植物病原真菌为作用对象,利用梯度稀释法对柳杉叶挥发油进行抗菌活性研究;利用GC-MS分析鉴定柳杉叶挥发油的主要化学成分,并且运用峰面积归一法确定各个成分的含量。研究结果表明:柳杉叶挥发油对产气肠杆菌、大肠杆菌、金黄色葡萄球菌和尖孢镰刀菌均有一定的抑制作用,其中对0.8 g∙mL−1尖孢镰刀菌的抗菌率为39.8%;柳杉叶挥发油的主要化学成分为萜类和醇类,含量较多的是(−)-扁枝烯(24.81%)、榄香醇(16.91%)、表桉叶油醇(8.72%)、α-蒎烯(7.06%)、β-芬兰烯(6.71%)、D-柠檬烯(4.81%)。因此,柳杉叶挥发油具有抗菌作用,萜类可能是主要有效抗菌成分。In order to establish a gas phase mass spectrometry (GC-MS) technique for the analysis of volatile oil components of Cryptomeria fortunei leaves and to study the antibacterial activity of the volatile oil. In this study, the volatile oil of Cryptomeria fortunei leaves was extracted by steam distillation, and the antibacterial activity of the volatile oil was studied by gradient dilution method with three common bacteria and one plant pathogen fungus as the target. The main chemical components of the volatile oil of Cryptomeria fortunei leaves were identified by GC-MS, and the content of each component was determined by peak area normalization method. The results showed that the volatile oil of Cryptomeria fortunei leaves had certain inhibitory effects on Enterobacter aerogenes, Escherichia coli, Staphylococcus aureus and Fusarium oxysporum, and the antibacterial rate against 0.8 g·mL−1 Fusarium oxysporum was 39.8%. The main components of the volatile oil of Cryptomeria fortunei leaves were terpenes and alcohols, the most abundant of which were (−)-platydene (24.81%), elemenol (16.91%), eutectol (8.72%), α-pinene (7.06%), β-Finlanene (6.71%) and D-limonene (4.81%). Therefore, the volatile oil of Cryptomeria fortunei leaves has antibacterial effect, and terpenoids may be the main effective antibacterial components.
关键词: 柳杉 ；挥发油 ；GC-MS分析 ；抗菌活性
摘要： Fruit diseases caused by postharvest fungal infections bring about significant losses to fruit farmers and traders. Green mold caused by Penicillium digitatum is particularly troublesome because it is responsible for up to 90% of the total citrus fruit losses post-harvest. The conventional use of chemical fungicides has significantly reduced the incidence of green mold disease and increased fruit shelf-life. However, they contaminate the environment, are a health risk to handlers and consumers, and have led to the emergence of resistant P. digitatum strains, hence complicating control of the disease. Plant essential oils and their bioactive components are thus considered better alternatives to the synthetic fungicides because they are generally safe, highly fungicidal, and with limited ability to induce drug resistance. A recent study in our laboratory showed that cuminaldehyde (CA), the major bioactive component of cumin essential oils, inhibited mycelial growth of P. digitatum to significantly delay green mold formation in citrus fruit. The fungicidal activity was due to oxidative stress characterized by accumulation of reactive oxygen species (ROS), increased lipid peroxidation, impairment of plasma membrane permeability, and eventual cell death. This doctoral study examined the antifungal mechanism of CA against P. digitatum, and the possible strategies to enhance its fungicidal potential. The main findings are summarized under the three categories below. 1.Molecular mechanism of cuminaldehyde inhibition of P. digitatum in citrus fruits DCFH-DA staining of the CA-treated mycelia and fluorimetric method for examination of hydrogen peroxide (H2O2) content revealed that the contents of ROS and H2O2 began to increase at 20 min of CA treatment. Analysis of NADH oxidase (NOX) activity using a NOX assay kit showed increased activity from 10 min. Transcriptome data from RNA sequencing analysis and proteome data from iTRAQ analysis disclosed a massive downregulation of membrane proteins from 10 min of incubation. The most affected proteins were those annotated to localization and transmembrane transport, and those integral to mitochondrial electron transport chain (mETC) complexes Ⅰ, Ⅳ, Ⅴ and the intermembrane space. Catalase (CAT), regulators of transcription and DNA replication, and proteins in the pathways of reduced glutathione (GSH) metabolism and folate biosynthesis were also downregulated. Analysis of GSH content and activity of CAT confirmed that they declined from the beginning of the experiment and 10 min, respectively. RT-qPCR analysis confirmed reduced expression of XM_014683121.1 and XM_014678114.1 (CAT genes), XM_014675255.1 (glutathione reductase), XP_014538126.1, XP_014530932.1, and XP_014530928.1 (folate metabolism), XM_014679237.1 (mETC complex Ⅰ), XM_014679619.1 (MICOS complex), XM_014683512.1 (metalloendopeptidase OMA1), and several membrane transporters and regulators of transcription and translation. Reduced expression of XM_014679237.1, XM_014679619.1, and XM_014683512.1 signaled possible damage to inner mitochondrial membrane (IMM). This was confirmed by a decline in mitochondrial membrane potential and a concomitant decline in total cellular ATP levels. Analysis of complex Ⅰ activity showed an increase in the rate of dehydrogenation of NADH to NAD+ from 10 min. This time corresponded to the onset of the rise in SOD activity, confirming the release of O2·- from complex Ⅰ. Complex Ⅲ activity began to increase from 20 min and continued to the end of the experiment. The results suggest that CA treatment instigated O2·- production (initially from mETC complex Ⅰ and then complex Ⅲ and other sources) while limiting the ability of the cells to protect themselves from the accumulating ROS by reducing the expression of GSH and CAT. This was possibly achieved by downregulation of transcription and replication regulators in the biosynthetic pathways of these antioxidants. The downregulation of transcription and replication regulators may have resulted from downregulation of folate biosynthesis or direct interaction of CA with the proteins. Failure of Pds01 cells to effectively scavenge ROS (due to reduced expression of CAT and GSH) led to the accumulation of H2O2 and other derived ROS, and the associated establishment of oxidative stress. 2.Biotransformation of cuminaldehyde by P．Digitatum In this section, we examined why there was accumulation of ROS in the mycelial cells within the first 30 min, yet no visible damage was caused to P. digitatum cells. Gas chromatography (GC) analysis revealed a steady decline in content of CA as the incubation time increased. GC results also showed accumulation of two new products, which were later identified by GC-MS and LC-MS analyses as cumin alcohol and p-cymene. Transcriptome and proteome data showed that pathways associated with biosynthesis of secondary metabolites, xenobiotic degradation and metabolism, and metabolism of terpenoids were activated. 32 and 46 upregulated DEGs were annotated to pathways involving biosynthesis of secondary metabolites at 10 and 30 min,
关键词: Citrus fruit ；Penicillium digitatum ；cuminaldehyde ；antifungal mechanism ；reactive oxygen species ；biotransformation
会议名称： 2016首届中国中药资源大会暨CSNR中药及天然药物资源研究专业委员会第十二届学术年会
会议时间： 2016-08-01
摘要： Endophytic fungi or endophytes exist widely inside the healthy tissues of living plants,and are important components of plant micro-ecosystems.Over the long period of evolution, some co-existing endophytes and their host plants have established a special relationship with one and another,which can significantly influence the formation of metabolic products in plants, then affect quality and quantity of crude drugs derived from medicinal plants.Our research group focused on the endophytic fungi and their correlations with the host medicinal plants.The following contents were carried out: (1) Research on endophytic fungi diversity and population structure;(2) Chemical diversity and bioactive secondary metabolites of endophytic fungi;(3)The effects of endophytic fungi on host plants and the correlation between the qualities of TCMs and endophytic fungi.More than 5000 endophytic fungal strains were isolated from more than 70 medicinal plants.In addition, fermented products of 32 strains of endophytic fungi with bio-activities were separated.More than 200 compounds were identified.Many endophytic fungi could produce secondary metabolites originally-found from host plants;some could promote the growth of host plant.For example, the fungus Z J44 was able to increase the growth of the host plant---adlay (Coix lacryma-jobi var.mayuen) and Arobidopis.Interestingly, one endophytic fungus D16 (Trichoderma atroviride) isolated from the root of Salvia miltiorrhiza, was found out to produce tanshinone Ⅰ and tanshinone Ⅱ A.Moreover, it was discovered that D16 could significantly enhance the biomass of S.miltiorrhiza hairy roots and promote the biosynthesis of tanshinones notably, and protein polysaccharide fraction (PSF) from D 16 was the main active fraction to promote tanshinone biosynthesis.Furthermore, technologies of metabolomics, transcriptomics and proteomics were used to investigate the molecular mechanism of PSF on the growth and secondary metabolism of S.miltiorrhiza hairy roots.The results indicate that the distribution and population structure of endophytes can be considerably affected by factors, such as the genetic background, age, and environmental conditions of their hosts.On the other hand, the endophytic fungi can also confer profound impacts on their host plants by enhancing their growth, increasing their fitness, strengthening their tolerances to abiotic and biotic stresses, and promoting their accumulation of secondary metabolites.