一株耐热珊瑚共附生真菌的鉴定及抗氧化活性的研究

Characterization of a Thermotolerant Coral Symbiotic and Epiphytic Fungus C21-5B and Its Antioxidant Activity

珊瑚共附生真菌及其代谢产物研究活跃,产物种类多样,活性丰富,但珊瑚中的耐热真菌未见报道。对耐热珊瑚共附生真菌C21-5B进行鉴定,研究其生理学特性及代谢产物的抗氧化活性,为该菌的深入研究及利用提供依据。通过形态学观察、18S rRNA序列分析鉴定菌株;通过测量不同海精盐浓度、pH、温度条件下的菌落直径研究该菌生理特性;根据DPPH自由基清除率、ABTS自由基清除率测定该菌抗氧化活性;通过薄层层析和高效液相色谱分析代谢产物活性成分。珊瑚真菌C21-5B经鉴定为土曲霉(Aspergillus terreus)。生理特性研究表明,菌株C21-5B能够生长的条件:海精盐浓度0.0%~20.0%、pH值2.0~12.0、温度15~45℃;最适生长条件:海精盐浓度0.5%~3.5%、pH值6.0~8.0、温度35℃。该菌代谢产物的乙酸乙酯萃取物具有较高的抗氧化活性,DPPH和ABTS自由基的EC50分别为0.113、0.504 mg/mL。经薄层层析和高效液相色谱分析,发现该菌代谢产物的中性极性成分偏多,含有生物碱、类脂化合物、还原性物质、黄酮类物质、芳香胺类。菌株C21-5B为耐热、兼性海洋真菌,具有极强的耐酸碱能力,代谢产物种类丰富,并具有明显的抗氧化活性,具有开发利用潜力。

Coral symbiotic and epiphytic fungi and their metabolites have been studied actively.The products are diverse and rich in bioactivity.Nevertheless,the thermotolerant fungi in corals have not been reported.The heat-resistant coral fungus Aspergillus terreus C21-5B was identified,its physiological characteristics,and the antioxidant activities were studied to provide a basis for further research and utilization of the fungus.The strain was identified by morphological observation and 18S rRNA sequence analysis;The physiological characteristics of the strain were studied by measuring the colony diameter under the condition of different concentration of sea table salts,pH and temperature;the antioxidant activities of the strain were determined based on the scavenging rate of DPPH free radical and ABTS free radical;the active components of C21-5 metabolism were analyzed by thin layer chromatography and high performance liquid chromatography.The coral fungus C21-5B was identified as Aspergillus terreus.The study on its physiological characteristics showed that the concentration of sea table salt for the growth of C21-5B was 0.0%-20.0%,pH 2.0-12.0,and temperature 15-45℃.The optimum growth conditions were that the concentration of sea table salt was 0.5%-3.5%,pH 6.0-8.0,and temperature 35℃.The metabolite extracted with ethyl acetate of the fungus C21-5 had comparatively high antioxidant activity,and the EC50 of DPPH and ABTS free radicals were 0.113 mg/mL and 0.504 mg/mL,respectively.It was found adopting the analysis with thin layer chromatography and high performance liquid chromatography that there were somewhat more polar components of neutrality,including alkaloids,lipoid compound,reducing substances,flavonoids and aromatic amines.Aspergillus terreus C21-5B is a thermotolerant and facultative anaerobic marine fungus,which has strong acid-base tolerance capacity,with abundant category of metabolites and obvious antioxidant activity,it has the potential of development and utilization.