Angucycline and angucyclinone derivatives from the marine-derived Streptomyces sp

Actinoquinazolinone, a New Quinazolinone Derivative from a Marine Bacterium Streptomyces sp. CNQ-617, Suppresses the Motility of Gastric Cancer Cells

A HPLC-UV guided fractionation of the culture broth of Streptomyces sp. CNQ-617 has led to the isolation of a new quinazolinone derivative, actinoquinazolinone (1), as well as two known compounds, 7-hydroxy-6-methoxy-3,4-dihydroquinazolin-4-one (2) and 7-methoxy-8-hydroxy cycloanthranilylproline (3). The interpretation of 1D, 2D NMR, and MS spectroscopic data revealed the planar structure of 1. Furthermore, compound 1 suppressed invasion ability by inhibiting epithelial-mesenchymal transition markers (EMT) in AGS cells at a concentration of 5 µM. In addition, compound 1 decreased the expression of seventeen genes related to human cell motility and slightly suppressed the signal transducer and activator of the transcription 3 (STAT3) signal pathway in AGS cells. Together, these results demonstrate that 1 is a potent inhibitor of gastric cancer cells.

Unique Cyclized Thiolopyrrolones from the Marine-Derived Streptomyces sp. BTBU20218885

Two new cyclized thiolopyrrolone derivatives, namely, thiolopyrrolone A (1) and 2,2-dioxidothiolutin (2), together with the kn own compound, thiolutin (3) were identified from a marine-derived Streptomyces sp. BTBU20218885, which was isolated from a mud sample collected from the coastal region of Xiamen, China. Their chemical structures were determined using spectroscopic data, including HRESIMS, 1D and 2D NMR techniques. 1 possessed a unique unsymmetrical sulfur-containing thiolopyrrolone structure. All the compounds were tested for bioactivities against Staphylococcus aureus, Escherichia coli, Bacille Calmette–Guérin (BCG), Mycobacterium tuberculosis, and Candida albicans. 1 displayed antibacterial activities against BCG, M. tuberculosis, and S. aureus with minimum inhibitory concentration (MIC) values of 10, 10, and 100 μg/mL, respectively. Thiolutin (3) showed antibacterial activities against E. coli, BCG, M. tuberculosis, and S. aureus with MIC values of 6.25, 0.3125, 0.625, and 3.125 μg/mL, respectively.