桐花树活性内生真菌筛选及其抗菌化学成分的研究

Screening of active endophytic fungi derived from Aegiceras corniculatum and their antibacterial chemical constituents

关键词:  桐花树, 内生真菌, 抑菌活性, 化学成分, 拟茎点霉属

Key words:  Aegiceras corniculatum, endophytic fungi, antibacterial activity, chemical constituents, Phomopsis

摘要:

为了探究桐花树内生真菌在抑菌方面的价值,该文以内生真菌发酵产物的抑菌作用为评价指标筛选活性菌株,采用生物活性跟踪方法结合多种色谱技术分离活性菌株的化学成分,通过波谱与文献数据比对鉴定单体化合物结构,并利用微孔板法测定单体化合物的抑菌活性。结果表明:(1)从桐花树分离得到的16株内生真菌分属2纲7目10科10属,镰刀菌属(Fusarium)为优势菌属。内生真菌GXIMD02029和GXIMD02039的发酵产物对枯草芽孢杆菌、表皮葡萄球菌、耐甲氧西林金黄色葡萄球菌、藤黄微球菌、粘性放线菌和金黄色葡萄球菌有不同程度的抑制作用,GXIMD02038发酵产物对耐甲氧西林金黄色葡萄球菌、藤黄微球菌和金黄色葡萄球菌有抑制作用。(2)7个化合物从内生真菌Phomopsis sp. GXIMD02029中被分离并鉴定为(15R)-acetoxydothiorelone A(1)、cytosporone B(2)、pestalotiopsone H(3)、pestalotiopsone B(4)、4-Hydroxybenzaldehyde(5)、p-Hydroxybenzoic acid(6)、N-(2-phenylethyl)acetamide(7)。(3)化合物1和2有不同程度的抑菌作用,化合物1对枯草芽孢杆菌、表皮葡萄球菌、耐甲氧西林金黄色葡萄球菌的MIC值为16.25 SymbolmA@ g·mL^-1,对藤黄微球菌和粘性放线菌的MIC值为7.812 5 SymbolmA@ g·mL^-1,对金黄色葡萄球菌的MIC值为31.25 SymbolmA@ g·mL^-1。化合物2对藤黄微球菌的MIC值为62.5 SymbolmA@ g·mL^-1,对枯草芽孢杆菌、表皮葡萄球菌、耐甲氧西林金黄色葡萄球菌、粘性放线菌的MIC值为125 SymbolmA@ g·mL^-1,对金黄色葡萄球菌的MIC值为250 SymbolmA@ g·mL^-1。该文筛选了3株活性菌株,首次报道化合物1具有抗菌活性,为桐花树内生真菌在抗菌价值方面提供了依据。

Abstract:

In order to explore the antibacterial activity of endophytic fungi derived from Aegiceras corniculatum, antibacterial activity of ferment extract of endophytic fungi was used as evaluation index to screen active strains, the chemical constituents were separated on the basis of bioactivity-guiding method combined with various chromatographic techniques and identified by spectral technique together with comparison with literature data, and the antibacterial activity of pure compounds was determined by microplate method. The results were as follows:(1)Sixteen taxa of endophytic fungi isolated from A. corniculatum were distributed in 2 classes, 7 orders, 10 families and 10 genera. Fusarium was dominant genus. The ferment extract of endophytic fungi GXIMD02029 and GXIMD02039 displayed different levels of inhibitory effects on Bacillus subtilis, Staphylococcus epidermidis, methicillin-resistant S. aureus, Micrococcus luteus, Actinomyces viscosity, and Staphylococcus aureus when that of GXIMD02038 against methicillin-resistant S. aureus, Micrococcus luteus, and Staphylococcus aureus.(2)Seven pure compounds were isolated from endophytic fungi Phomopsis sp. GXIMD02029 and identified as(15R)-acetoxydothiorelone A(1), cytosporone B(2), pestalotiopsone H(3), pestalotiopsone B(4), 4-Hydroxybenzaldehyde(5), p-Hydroxybenzoic acid(6), N-(2-phenylethyl)acetamide(7).(3)Compounds 1 and 2 showed different levels of antibacterial effects. Compound 1 exhibited inhibitory effect on Bacillus subtilis, Staphylococcus epidermidis and methicillin-resistant S. aureus with MIC value of 16.25 SymbolmA@ g·mL^-1, Micrococcus luteus and Actinomyces viscosity with MIC value of 7.812 5 SymbolmA@ g·mL^-1, and Staphylococcus aureus with MIC value of 31.25 SymbolmA@ g·mL^-1. Compound 2 displayed inhibitory effect on Micrococcus luteus with MIC value of 62.5 SymbolmA@ g·mL^-1, Bacillus subtilis, Staphylococcus epidermidis, methicillin-resistant S. aureus and Actinomyces viscosity with MIC values of 125 SymbolmA@ g·mL^-1, and Staphylococcus aureus with MIC value of 250 SymbolmA@ g·mL^-1. Three active strains were reported in the project. It is reported that Compound 1 shows the antibacterial activity for the first time. The result provides the basis for the antibacterial values of endophytic fungi of Aegiceras corniculatum.