Bioactive Streptoglutarimides A–J from the Marine-Derived Streptomyces sp. ZZ741

The new streptoglutarimides A–J (1–10) and the known streptovitacin A (11) were isolated from a marine-derived actinomycete, Streptomyces sp. ZZ741. Structures of the isolated compounds were elucidated based on their HRESIMS data, extensive NMR spectroscopic analyses, ECD calculations, Mosher′s method, and a single-crystal X-ray diffraction experiment. Streptoglutarimide H (8) and streptovitacin A (11) showed potent antiproliferative activity against human glioma U87MG and U251 cells with IC50 values of 1.5–3.8 μM for 8 and 0.05–0.22 μM for 11. All isolated compounds exhibited antimicrobial activity with MIC values of 9–11 μg/mL against methicillin-resistant Staphylococcus aureus, 8–12 μg/mL against Escherichia coli, and 8–20 μg/mL against Candida albicans.