一株产鬼臼毒素内生真菌的分离及其代谢产物抗小鼠S180肉瘤的研究

Isolation of a podophyllotoxin-producing endophytic fungus from Sinopodophyllum hexandrum and the anti-S180 sarcoma activity of its fermentation broth in mice

目的从秦岭濒危药用桃儿七(Sinopodophyllum hexandrum)植株内分离出产鬼臼毒素(podophyllotoxin)的内生真菌,研究其发酵液的抑瘤活性。方法采用组织分离法分离、纯化桃儿七植株根、茎部位的内生真菌,逐一鉴定其代谢产物,筛选出能够产鬼臼毒素的内生真菌。采用动物体内抑瘤实验研究内生真菌发酵液对小鼠S180肉瘤的抑制作用,并对荷瘤小鼠眼眶取血进行白细胞及淋巴细胞计数。结果分离出一株产鬼臼毒素的内生真菌T8,鉴定为Cephalosporium sp.。T8发酵液实验动物组的肿瘤质量低于模型组,大于环磷酰胺组(P<0.05),且其抑制率低于环磷酰胺(P<0.05)。T8发酵液能够促进白细胞和淋巴细胞的增殖。结论 T8发酵液具有一定的抑制肿瘤生长的作用,经减毒处理后可以作为肿瘤治疗的辅助药物。

Objective To isolate an endophytic fungus,which can produce podophyllotoxin,from an endangered medical plant Sinopodophyllum hexandrum,and to investigate the inhibitory effect of its fermentation broth against S180 sarcoma.Methods Endophytic fungal strains were isolated and purified by microbiological tissue isolating methods from the fresh roots and stems of Sinopodophyllum hexandrum.The fermentation broths of the isolates were investigated by HPLC,so as to screen for podophyllotoxin-producing strains.The antitumor effects of endophytic fungus fermentation broths were evaluated in a mouse model bearing S180 sarcoma.The orbital blood samples were obtained for leukocyte and lymphocyte count.Results Strain T8,identified as Cephalosporium sp.was podophyllotoxin-producing.The tumor weight of T8 group was lower than that of the model group（P 0.05） and higher than that of the cyclophosphamide group（P 0.05）.The inhibitory rate of fermentation broth of T8 group was significantly lower than that of cyclophosphamide group（P 0.05）.Compared with the model group,the fermentation broth of T8 group significantly promoted the proliferation of leukocytes and lymphocytes.Conclusion The fermentation broth of fungus T8 can inhibit tumor growth and may serve as an adjuvant drug for tumor therapy after attenuation.