Three naphthomycin type polyketide compounds isolated from strain Streptomyces sp. HKIB0008
Yuan Chen1,2, Fei Zhang1,2, Zi-Kang Zhao1
1State Key Laboratory of Phytochemistry and Natural Medicines, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming, 650201, Yunnan, P. R. China.
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Three new naphthomycin derivatives were isolated and identified from Streptomyces sp. HKIB0008, and were designated as naphthomycin R (1), naphthomycin S (2), and naphthomycin T (3). Their structures were elucidated using a combination of spectroscopic techniques, including high-resolution mass spectrometry, and NMR. The naphthoquinone core of 1 underwent carbon-carbon bond cleavage, resulting in a novel structural feature, and a corresponding Baeyer-Villiger oxidation mechanism was proposed. Compounds 2 and 3 possess a complex side chain when compared to known cystine modification on the naphthalenoid core as in the case of naphthomycins I and J. In addition, the minimum inhibitory concentration (MIC) assays for these compounds were conducted.
