Antibacterial Prenylated Acylphloroglucinols from Psorothamnus fremontii

作者:Yu, Qian; Ravu, Ranga Rao; Xu, Qiong-Ming; Ganji, Suresh; Jacob, Melissa R.; Khan, Shabana I.; Yu, Bo-Yang; Li, Xing-Cong*
来源:Journal of Natural Products, 2015, 78(11): 2748-2753.
DOI:10.1021/acs.jnatprod.5b00721

摘要

Psorothatins A-C (1-3), three antibacterial prenylated acylphloroglucinol derivatives, were isolated from the native American plant Psorothamnus fremontii. They feature an unusual alpha,beta-epoxyketone functionality and a beta-hydroxy-alpha,beta-unsaturated ketone structural moiety. The latter forms a pseudo-six-membered heterocyclic ring due to strong intramolecular hydrogen bonding, as indicated by the long-range proton-carbon correlations in the NMR experiments. Psorothatin C (3) was the most active compound against methicillin-resistant Staphylococcus aureus and vancomycin-resistant Enterococcus faecium, with IC50 values in the range 1.4-8.8 mu g/mL. The first total synthesis of 3 described herein permits future access to structural analogues with potentially improved antibacterial activities.