Three new angucycline glycosides, designated grincamycin I (1), J (2), and K (3), together with the known congener A-7884 (4), were isolated from marine-derived actinomycete Streptomyces lusitanus SCSIO LR32. The structures of the new compounds were elucidated by comprehensive spectral data analysis. Compounds 2 and 4 exhibited antitumor activity against human cancer cells MDA-MB-435, MDA-MB-231, NCI-H460, HCT-116 and HepG2, and human normal breast epithelial cell MCF10A with IC50 values ranging from 0.4 to 6.9 µM. In addition, A-7884 (4) demonstrated antimicrobial activity against Micrococcus luteus with an MIC value of 1.95 µg/mL.
Seven new polyketides named fusarisolins F-K (1–6) and fusarin I (7) were isolated from the marine-derived fungus Fusarium solani 8388, together with the known anhydrojavanicin (8), 5-deoxybostry coidin (9), and scytalol A (10). Their structures were established by comprehensive spectroscopic data analyses, and by comparison of the 1H and 13C NMR data with those reported in literature. Fusarisolin F (1) contained both a dichlorobenzene group and an ethylene oxide unit, which was rare in nature. In the bioassays, fusarisolin I (4), fusarisolin J (5), and 5-deoxybostry coidin (9) exhibited obvious antibacterial activities against methicillin-resistant Staphylococcus aureus n315 with MIC values of 3, 3, and 6 μg/mL, respectively. Fusarisolin H (3) and fusarisolin J (5) showed inhibitory effects against methicillin-resistant Staphylococcus aureus NCTC 10442 with the same MIC value of 6 μg/mL. With the exception of 5, all other compounds did not show or showed weak cytotoxicities against HeLa, A549, and KB cells; while fusarisolin J (5) demonstrated moderate cytotoxicities against the three human cancer cell lines with CC50 values between 9.21 and 14.02 μM.
Two new alkaloids designated aspernigrin E (1) and pyranonigrin L (2) were isolated from mangrove endophytic fungus Aspergillus fumigatus SAS10, together with the known alkaloid compounds pyranonigrin A (3), asperazine (4), (+)-iso-pestalazine A (5), pestalazine A (6), and pestalazine B (7). The planar structures of the new compounds were elucidated by HR-MS and NMR spectroscopic data analyses. The absolute configurations of compounds 1 and 2 were determined by comparison of the electronic circular dichroic (ECD) spectra with the calculated ECD spectra. All these compounds were tested for anti-bacterial activity.