Benwamycins A–G, Trialkyl-Substituted Benzene Derivatives from a Soil-Derived <i>Streptomyces</i>
Feng-Xian Yang, Jianping Huang, Zhixiang Liu, Zhiyan Wang, Jing Yang, Jun Tang, Zhiyin Yu, Yijun Yan, Guoyin Kai, Sheng‐Xiong Huang
Abstract
Seven new trialkyl-substituted benzene derivatives named benwamycins A–G (1–7), together with three known congeners, 8–10, were isolated from culture broth of the soil-derived Streptomyces sp. KIB-H1471. Their structures were elucidated by using 1D and 2D NMR analyses in combination with HRESIMS data. The absolute configurations of 1–9 were determined by chemical conversion and comparison of circular dichroism spectra and confirmed for 1 by single-crystal X-ray crystallography. Compounds 6 and 7 have a unique γ-pyrone-like ring on one side chain. Compounds 2 and 6 inhibited human T cell proliferation with IC50 values of 14.3 and 12.5 μM, respectively, without obvious cytotoxicity for naïve human T cells. Compounds 3 and 6 could weakly enhance insulin-stimulated glucose uptake.