Isolation, Structure Elucidation, and First Total Synthesis of Quinomycins K and L, Two New Octadepsipeptides from the Maowei Sea Mangrove-Derived <i>Streptomyces</i> sp. B475

Mangrove actinomycetia have been proven to be one of the promising sources for discovering novel bioactive natural products. Quinomycins K (<b>1</b>) and L (<b>2</b>), two rare quinomycin-type octadepsipeptides without intra-peptide disulfide or thioacetal bridges, were inves...

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Bibliographic Details
Main Authors: Qinpei Lu, Gang Wu, Xiaomeng Hao, Xinxin Hu, Hao Cai, Xiujun Liu, Xuefu You, Hongwei Guo, Chenghang Sun
Format: Article
Language:English
Published: MDPI AG 2023-02-01
Series:Marine Drugs
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Online Access:https://www.mdpi.com/1660-3397/21/3/143
Description
Summary:Mangrove actinomycetia have been proven to be one of the promising sources for discovering novel bioactive natural products. Quinomycins K (<b>1</b>) and L (<b>2</b>), two rare quinomycin-type octadepsipeptides without intra-peptide disulfide or thioacetal bridges, were investigated from the Maowei Sea mangrove-derived <i>Streptomyces</i> sp. B475. Their chemical structures, including the absolute configurations of their amino acids, were elucidated by a combination of NMR and tandem MS analysis, electronic circular dichroism (ECD) calculation, advanced Marfey’s method, and further unequivocally confirmed by the first total synthesis. The two compounds displayed no potent antibacterial activity against 37 bacterial pathogens and had no significant cytotoxic activity against H460 lung cancer cells.
ISSN:1660-3397