Six phenazines including three new ones were isolated from the culture of a marine actinomycete Streptomyces sp. 182SMLY. Based on the analyses of NMR, HRESIMS, optical rotation value, and CD data, the structures of these isolated compounds were determined as new phenazines of (-)-streptophenazines M-O and known phenazines of 1-carbomethoxyphenazine and (-)-streptophenazines A and B. (-)-Streptophenazine B showed activity in suppressing the growth of methicillin-resistant Staphylococcus aureus with MIC value of 4.2 μg/mL.
Keywords: (-)-streptophenazine B; (-)-streptophenazines M–O; Streptomyces sp. 182SMLY; antibacterial activity.