Tanapichatsakul Chutima, Khruengsai Sarunpron, Monggoot Sakon, Pripdeevech Patcharee
School of Science, Mae Fah Luang University, Muang, Chiang Rai, Thailand.
Milott Laboratories Co., Ltd., Bangplee, Samutprakarn, Thailand.
PeerJ. 2019 Feb 12;7:e6427. doi: 10.7717/peerj.6427. eCollection 2019.
Endophytic fungi, which colonize within a host plant without causing any apparent diseases, have been considered as an important source of bioactive secondary metabolites containing antimicrobial and antioxidant activities. The aim of this research was to isolate the endophytic fungi of and then to screen their antimicrobial and antioxidant activities. A total of 11 fungal endophytes were isolated from healthy leaves of belonging to six genera: , , , , , and . All isolated strains were cultured and further extracted with ethyl acetate solvent. Antimicrobial activity of all crude endophytic fungal extracts was analyzed using disc diffusion assay against six bacterial and two fungal pathogens. Crude extracts of strains MFLUCC15-1130 and MFLUCC15-1131 showed broad-spectrum antimicrobial activity against all tested pathogens. Activity against and was notable, showing the lowest minimum inhibitory concentration at 3.91 μg/mL. Antioxidant activity of all crude endophytic fungal extracts was also evaluated based on 2,2-diphenyl-1-picrylhydrazyl assay. Significant antioxidant activity was detected in the crude extracts of fungus MFLUCC15-1130 and MFLUCC15-1131 with IC of 22.92 ± 0.67 and 37.61 ± 0.49 μg/mL, respectively. Using molecular identification, MFLUCC15-1130 and MFLUCC15-1131 were identified as sp. and sp., respectively. The major chemical constituents produced by both crude extracts were identified by gas chromatography-mass spectrometry. Eugenol, myristaldehyde, lauric acid, and caprylic acid were the primary antimicrobial and antioxidant compounds in both crude extracts. This is the first report of eugenol being a biologically active compound of sp. and sp. fungal endophytes. Eugenol has been reported as antimicrobial and antioxidant agents with agronomic applications. Thus the two newly-isolated endophytes may be used for eugenol production, which in turn can be used in a variety of applications.
内生真菌定殖于宿主植物内部却不引发任何明显病害，被视为具有抗菌和抗氧化活性的生物活性次生代谢产物的重要来源。本研究旨在分离[植物名称未给出]的内生真菌，进而筛选其抗菌和抗氧化活性。从[植物名称未给出]的健康叶片中共分离出11株真菌内生菌，分属于六个属：[六个属名未给出]。所有分离菌株进行培养，并用乙酸乙酯溶剂进一步提取。采用纸片扩散法分析所有内生真菌粗提物对六种细菌和两种真菌病原体的抗菌活性。菌株MFLUCC15 - 1130和MFLUCC15 - 1131的粗提物对所有测试病原体均表现出广谱抗菌活性。对[两种病原体名称未给出]的活性尤为显著，最低抑菌浓度低至3.91μg/mL。还基于2,2 - 二苯基 - 1 - 苦基肼法评估了所有内生真菌粗提物的抗氧化活性。在真菌MFLUCC15 - 1130和MFLUCC15 - 1131的粗提物中检测到显著的抗氧化活性，其IC50分别为22.92±0.67μg/mL和37.61±0.49μg/mL。通过分子鉴定，MFLUCC15 - 1130和MFLUCC15 - 1131分别被鉴定为[两种菌种名称未给出]。通过气相色谱 - 质谱联用鉴定了两种粗提物产生的主要化学成分。丁香酚、肉豆蔻醛、月桂酸和辛酸是两种粗提物中的主要抗菌和抗氧化化合物。这是丁香酚作为[两种菌种名称未给出]真菌内生菌生物活性化合物的首次报道。丁香酚已被报道为具有农业应用价值的抗菌和抗氧化剂。因此，这两种新分离的内生菌可用于生产丁香酚，进而可用于多种应用。
