Novel cyclohexene and benzamide derivatives from marine-associated Streptomyces sp. ZZ502

Three new compounds and the known benzamides of 2-acetamido-3-hydroxybenzamide, 2-amino-3-hydroxybenzamide, and 2-aminobenzamide were isolated from the culture of a marine actinomycete Streptomyces sp. ZZ502. Structures of the new compounds were determined as 3-amino-2-carboxamine-6(R)-chloro-4(R),5(S)-dihydroxy-cyclohex-2-en-1-one, 3-amino-2-carboxamine-4(S),6(S)-dihydroxy-cyclohex-2-en-1-one, and 3-hydroxy-2-propionamidobenzamide based on extensive NMR spectroscopical analysis, HRESIMS data, ECD calculation, and X-ray diffraction analysis. None of these isolated compounds showed activity in inhibiting the proliferation of glioma cells nor the growth of methicillin-resistant Staphylococcus aureus, Escherichia coli, and Candida albicans.