Bioactive secondary metabolites from the marine-associated fungus Aspergillus terreus

Three new compounds, including a prenylated tryptophan derivative, luteoride E (1), a butenolide derivative, versicolactone G (2), and a linear aliphatic alcohol, (3E,7E)-4,8-dimethyl-undecane-3,7-diene-1,11-diol (3), together with nine known compounds (4-12), were isolated and identified from a coral-associated fungus Aspergillus terreus. Their structures were elucidated by HRESIMS, one- and two-dimensional NMR analysis, and the absolute configuration of 2 was determined by comparison of its electronic circular dichroism (ECD) spectrum with the literature. Structurally, compound 1 featured an unusual (E)-oxime group, which occurred rarely in natural products. Compounds 1-3 were evaluated for the alpha-glucosidase inhibitory activity, and compound 2 showed potent inhibitory potency with IC50 value of 104.8 +/- 9.5 mu M, which was lower than the positive control acarbose (IC50 = 154.7 +/- 8.1 mu M). Additionally, all the isolated compounds were evaluated for the anti-inflammatory activity against NO production, and compounds 1-3, 5-7, and 10 showed significant inhibitory potency with IC50 values ranging from 5.48 to 29.34 mu M.