柳珊瑚共附生真菌Alternaria sp.(WZL003)抑菌化合物的分离及其作用机制初步研究

Isolation of antibacterial macrosporin from gorgonian-derived fungus Alternaria sp.and preliminary study on its antimicrobial mechanism

目的研究1株柳珊瑚共附生真菌具有抑菌活性次级代谢产物及抑菌作用机制。方法采用活性追踪分离的方法,运用硅胶柱层析、Sephadex LH-20凝胶柱层析和半制备HPLC等手段,对采自中国南海的柳珊瑚Echinogorgia rebekka中分离获得的共附生链格孢霉属真菌Alternaria sp.(WZL003)的发酵产物进行分离和纯化,利用NMR、MS等波谱方法,并与文献对照,确定化合物的结构;以海洋病原菌和污损菌鳗弧菌Vibrio anguillarum为对象研究化合物的抑菌作用机制。结果从该菌发酵液的乙酸乙酯提取物中,分离获得1个对V.anguillarum具有较强抑菌活性的蒽醌类化合物macrosporin。结论初步的抑菌作用机制研究发现,该化合物能破坏鳗弧菌的细胞壁和细胞膜,导致细胞通透性增加,胞内大量内容物外泄,最终导致菌体死亡,从而起到抑菌作用。本研究首次报道了macrosporin对鳗弧菌的抑菌作用及其作用机制。

Objective To investigate the antibacterial secondary metabolite and its preliminary antimicrobial mechanism of a gorgonian-derived fungus.Methods Under the guidance of bioassay,column chromatography on silica gel and Sephadex LH-20,and semi-preparative HPLC were used to isolate and purify the metabolite from the fermentation products of Alternariasp.（WZL003）,a fungus was obtained from gorgonian Echinogorgia rebekka collected from the South China Sea.The structures of the isolated compounds were identified by spectroscopic analysis including NMR and MS,and by comparison with the data of literature.The antimicrobial mechanism of the compound against marine pathogenic Vibrio anguillarum was studied.Results One antibacterial compound-macrosporin was isolated from the EtOAc extracts of the culture broth of Alternariasp.（WZL003）.ConclusionIt was found that macrosporin killed the bacteria by destructing the cell wall and cytoplasmic membrane,leading to the increase of cell permeability,thus resulting in the extravasation of cell content.This is the first report on the antibacterial activity and antimicrobial mechanism of macrosporin against marine bacteriumV.anguillarum.