title: Metabolites from Aspergillus fumigatus, an endophytic fungus associated with Melia azedarach, and their antifungal, antifeedant, and toxic activities.
abstract: Thirty-nine fungal metabolites 1-39, including two new alkaloids, 12β-hydroxy-13α-methoxyverruculogen TR-2 (6) and 3-hydroxyfumiquinazoline A (16), were isolated from the fermentation broth of Aspergillus fumigatus LN-4, an endophytic fungus isolated from the stem bark of Melia azedarach. Their structures were elucidated on the basis of detailed spectroscopic analysis (mass spectrometry and one- and two-dimensional NMR experiments) and by comparison of their NMR data with those reported in the literature. These isolated compounds were evaluated for in vitro antifungal activities against some phytopathogenic fungi, toxicity against brine shrimps, and antifeedant activities against armyworm larvae (Mythimna separata Walker). Among them, sixteen compounds showed potent antifungal activities against phytopathogenic fungi (Botrytis cinerea, Alternaria solani, Alternaria alternata, Colletotrichum gloeosporioides, Fusarium solani, Fusarium oxysporum f. sp. niveum, Fusarium oxysporum f. sp. vasinfectum, and Gibberella saubinettii), and four of them, 12β-hydroxy-13α-methoxyverruculogen TR-2 (6), fumitremorgin B (7), verruculogen (8), and helvolic acid (39), exhibited antifungal activities with MIC values of 6.25-50 μg/mL, which were comparable to the two positive controls carbendazim and hymexazol. In addition, of eighteen that exerted moderate lethality toward brine shrimps, compounds 7 and 8 both showed significant toxicities with median lethal concentration (LC(50)) values of 13.6 and 15.8 μg/mL, respectively. Furthermore, among nine metabolites that were found to possess antifeedant activity against armyworm larvae, compounds 7 and 8 gave the best activity with antifeedant indexes (AFI) of 50.0% and 55.0%, respectively. Structure-activity relationships of the metabolites were also discussed.
authors.affiliation: Shaanxi Engineering Center of Bioresource Chemistry & Sustainable Utilization, College of Science, Northwest A&F University, Yangling, Shaanxi, China.
authors.forename: Xiao-Jun
authors.initials: XJ
authors.lastname: Li
authors.forename: Qiang
authors.initials: Q
authors.lastname: Zhang
authors.forename: An-Ling
authors.initials: AL
authors.lastname: Zhang
authors.forename: Jin-Ming
authors.initials: JM
authors.lastname: Gao
mesh_terms: D000818:Animals; D000935:Antifungal Agents / Q000737:chemistry / Q000378:metabolism* / Q000633:toxicity*; D001156:Artemia / Q000187:drug effects / Q000502:physiology*; D001232:Aspergillus fumigatus / Q000737:chemistry / Q000378:metabolism*; D060026:Endophytes / Q000737:chemistry / Q000378:metabolism*; D005247:Feeding Behavior / Q000187:drug effects; D005658:Fungi / Q000187:drug effects / Q000502:physiology; D031586:Melia azedarach / Q000382:microbiology*; D009036:Moths / Q000187:drug effects / Q000502:physiology*; D010935:Plant Diseases / Q000382:microbiology; D013329:Structure-Activity Relationship
chemical_list: D000935:Antifungal Agents