Seven previously undescribed compounds, including four diketomorpholine alkaloids (1‒4), one indole diketopiperazine alkaloid (9), one chromone (10), and one benzoic acid derivative (13), and nine known compounds (5-8, 11, 12, and 14-16) were isolated from two different fungal sources. Nine of these metabolites (1-9) were obtained from a seagrass-derived Aspergillus alabamensis SYSU-6778, while the others were obtained from a mixed culture of A. alabamensis SYSU-6778 and a co-isolated fungus A. fumigatiaffinis SYSU-6786. The chemical structures of the compounds were deduced via spectroscopic techniques (including HRESIMS, 1D and 2D NMR), chemical reactions, and ECD calculations. It is worth noting that compound 10 was identified as a defensive secondary metabolite of strain SYSU-6786, produced through the induction of compound 8 under co-culture conditions. Compounds 3 and 4 possessed a naturally rare isotryptophan core. Moreover, compounds 1 and 2 exhibited potent inhibitory activities against fish pathogenic bacterium Edwardsiella ictalurid, with minimum inhibitory concentration values of 10.0 μg/mL for both compounds.

Genus Penicillium comprising the most important and extensively studied fungi has been well-known as a rich source of secondary metabolites. Our study aimed to analyze and investigate biological activities, including in vitro anti-cancer, anti-inflammatory and anti-diabetic properties, of metabolites from a marine-derived fungus belonging to P. levitum. The chemical compounds in the culture broth of P. levitum strain N33.2 were extracted with ethyl acetate. Followingly, chemical analysis of the extract leaded to the isolation of three ergostane-type steroid components, namely cerevisterol (1), ergosterol peroxide (2), and (3β,5α,22E)-ergosta-6,8(14),22-triene-3,5-diol (3). Among these, (3) was the most potent cytotoxic against human cancer cell lines Hep-G2, A549 and MCF-7 with IC50 values of 2.89, 18.51, and 16.47 µg/mL, respectively, while the compound (1) showed no significant effect against tested cancer cells. Anti-inflammatory properties of purified compounds were evaluated based on NO-production in LPS-induced murine RAW264.7 macrophages. As a result, tested compounds performed diverse inhibitory effects on NO production by the macrophages, with the most significant inhibition rate of 81.37 ± 1.35% at 25 µg/mL by the compound (2). Interestingly, compounds (2) and (3) exhibited inhibitory activities against pancreatic lipase and α-glucosidase enzymes in vitro assays. Our study brought out new data concerning the chemical properties and biological activities of isolated steroids from a P. levitum fungus.

One new cyclohexenone derivative (1), and two undescribed drimane sesquiterpenes (2 and 3), together with another seven known drimane sesquiterpenes were isolated from a seagrass-derived fungus Aspergillus insuetus SYSU6925. Structures of these metabolites were elucidated by comprehensive spectroscopic analysis, including NMR analysis, mass spectrometry, and ECD calculations. Compounds 1-3, 5 and 7 displayed weak to moderate antifungal activities towards four phytopathogenic fungi, with Minimum inhibition concentration (MIC) values range from 50 to 200 μg/mL. Compound 1, a rare cyclohexenone derivative with n-propyl group exhibited more potent inhibitory activities (MIC, 50 μg/mL) against F. oxysporum than positive control (Triadimefon). Compounds 2 and 3 also exhibit potent anti-inflammatory activities by inhibiting the production of nitric oxide (NO) in RAW264.7 cells with IC50 values of 21.5±1.1 and 32.6±1.16 μM, respectively.