一株高抗氧化活性内生真菌的分子鉴定及产酚酸类物质研究

Molecular characterization and phenolic acids analysis of an endophytic fungus with high antioxidant activity

摘要:

【目的】以疏花水柏枝(Myricaria laxiflora)淹水前根部分离到的内生真菌SG17为研究对象，为明确其抗氧化能力及可能的物质基础，对其进行生物学鉴定、抗氧化能力分析及产酚酸类物质研究。【方法】对该菌nrDNA的内转录间隔区进行测序；应用总抗氧化试剂盒，以维生素C为阳性对照，测定其抗氧化能力；采用高效液相色谱(HPLC)和薄层色谱(TLC)探讨其发酵液中的酚酸类化合物。【结果】SG17具有很高的抗氧化活性，其发酵液粗提物的抗氧化活性达到同浓度抗坏血酸的31.86%，分子和形态鉴定表明SG17是一株烟曲霉(Aspergillus fumigatus)。其发酵产物中酚酸类物质含量丰富，HPLC能检测到含有没食子酸，且通过HPLC和TLC分析还发现一种光学性质与绿原酸极为相似的类似物。【结论】内生真菌烟曲霉SG17发酵液的抗氧化能力远高于国际报道水平，是一种具有潜在开发价值的抗氧化剂资源。

Abstract:

[Objective] An endophytic fungus SG17 was isolated from the root of Myricaria laxiflora before flooding. In order to explore the antioxidant capacity and the possible material foundation, bio-identification, antioxidant confirmation and phenolic acids analysis were conducted here. [Methods] The internal transcribed spacer (ITS) of nrDNA was sequenced, and a total antioxidant kit was used to measure the capacity with the positive control of Vitamin C. Furthermore, High performance liquid chromatography (HPLC) and thin layer chromatography (TLC) were applied to analyze the natural phenolic compounds from the fermentation broth. [Results] The antioxidant capacity of SG17 was extraordinarily high, and the extract of the fermentation liquid was 31.86% as high as the same content of vitamin C. ITS sequence and BLAST analysis indicated that SG17 would be Aspergillus fumigates, and this conclusion was further proved by morphological characterization. The contents of phenolic acids were rich in the fermentation broth, in which gallic acid could be detected by HPLC, and a compound with the same UV spectrum as chlorogenic acid was found both by HPLC and TLC. [Conclusion] The endophyte SG17, an Aspergillus fumigatus, had much higher antioxidant activity than reported before, and could be explored as a potential antioxidant resource in the future.