title: Phytotoxic, Antifungal and Immunosuppressive Metabolites from Aspergillus terreus QT122 Isolated from the Gut of Dragonfly.
abstract: Insect gut microbes have been considered as a resource for bioactive metabolites. The aim of this study was to characterize the compounds of a fungus Aspergillus terreus QT122 associated with the gut of dragonfly. Five main phytotoxic, antifungal, and immunosuppressive substances were isolated from the fungus QT122. The structures of such compounds were identified as emodin (1), 1-methyl emodin (2), terrein (3), methyl 6-acetyl-4-methoxy-7,8-dihydroxynaphthalene-2-carboxylate (4), and dihydrogeodin (5) on the basis of spectroscopic analysis and by comparison of the corresponding data to those reported in the literature previously. The compound 3 exhibited the best phytotoxic activity against the radicle growth of A. retroflexus L. and E. crusgalli L. with their IC50values of 11.2 and 3.1 μg/mL, which were comparable to that of the positive control of 2,4-dichlorophenoxyacetic acid (2,4-D) with the IC50values of 8.1 and 1.6 μg/mL, respectively. The compounds 2-3 showed potent antifungal activity in the growth of Alternaria solani with the IC50value of less than 0.1 μg/mL and the compound 2 also had great inhibitory effect against the growth of Fusarium oxysporum f. sp. cucumerinum (IC50< 0.1 μg/mL), which was comparable to that of referenced cycloheximide with IC50value of below 0.1 μg/mL. The compounds 3-5 exhibited strong immunosuppressive activities against the T cell viability with the inhibition rates of more than 99%, which were comparable to positive cyclosporin A under the concentration of 20 μM. These results suggest that the compounds 2-5 have the potential to be used as bio-control agents in agriculture or immunosuppressive agents.
authors.affiliation: College of Chemistry and Life Sciences, Zhejiang Normal University, Jinhua, 321004, People's Republic of China.
authors.forename: Yi-Hui
authors.initials: YH
authors.lastname: Lu
authors.affiliation: College of Chemistry and Life Sciences, Zhejiang Normal University, Jinhua, 321004, People's Republic of China.
authors.forename: Li-Ping
authors.initials: LP
authors.lastname: Jin
authors.affiliation: College of Chemistry and Life Sciences, Zhejiang Normal University, Jinhua, 321004, People's Republic of China.
authors.forename: Li-Chun
authors.initials: LC
authors.lastname: Kong
authors.affiliation: College of Chemistry and Life Sciences, Zhejiang Normal University, Jinhua, 321004, People's Republic of China. ylzhang@zjnu.cn.
authors.forename: Ying-Lao
authors.initials: YL
authors.lastname: Zhang
mesh_terms: D000818:Animals; D000935:Antifungal Agents / Q000737:chemistry / Q000378:metabolism / Q000494:pharmacology*; D001230:Aspergillus / Q000737:chemistry* / Q000145:classification / Q000302:isolation & purification / Q000378:metabolism*; D002470:Cell Survival / Q000187:drug effects; D005658:Fungi / Q000187:drug effects; D000069196:Gastrointestinal Microbiome; D041981:Gastrointestinal Tract / Q000382:microbiology; D006540:Herbicides / Q000737:chemistry / Q000378:metabolism / Q000494:pharmacology*; D007166:Immunosuppressive Agents / Q000737:chemistry / Q000378:metabolism / Q000494:pharmacology*; D015394:Molecular Structure; D063191:Odonata / Q000382:microbiology*; D057685:Plant Weeds / Q000187:drug effects; D064210:Secondary Metabolism; D013601:T-Lymphocytes / Q000166:cytology / Q000187:drug effects
chemical_list: D000935:Antifungal Agents; D006540:Herbicides; D007166:Immunosuppressive Agents