Suncheonosides E-M and Benzothioate Derivatives from the Marine-Derived Streptomyces sp. ZSN77

Thirteen new compounds, including suncheonosides E-M (1-9), four benzothioate derivatives (10-13), and one known compound (14), were identified from the marine-derived Streptomyces sp. ZSN77. Suncheonosides E-M incorporate β-d-glucose, while the reported suncheonosides (A-D) incorporate only l-rhamnose. All of the structures were determined by extensive analysis of NMR spectroscopic and HRESIMS data. Bioactivity evaluation of these compounds showed that 6 had significant activity against PC3 cells with an IC₅₀ value of 4.1 ± 0.1 μM, while compounds 12 and 14 exhibited cytotoxicity against HCT116 cells with IC₅₀ values of 7.3 ± 0.4 and 3.9 ± 0.3 μM, respectively. In addition, compounds 1, 2, 6, 10, and 14 displayed potent in vivo anti-inflammatory efficacy with inhibition of NO production in a dose-dependent manner.