posted on 2020-03-18, 19:34authored byHuimin Zhao, Aiping Yang, Jian Liu, Sheng Bao, Ren Peng, Yang Hu, Tianjie Yuan, Shurong Hou, Tian Xie, Qichun Zhang, Xiabin Chen, Xiachang Wang, Lihong Hu
A novel 6/6/5/6 tetracyclic
polyketide named chartspiroton (1) was isolated from
a medicinal plant endophytic Streptomyces in Dendrobium officinale. The
complete structure assignment with absolute stereochemistry was elucidated
through spectroscopic data, computational calculations, and single-crystal
X-ray diffraction. Chartspiroton features an unprecedented naphthoquinone
derivative spiro-fused with a benzofuran lactone moiety. A plausible
polyketide biosynthetic pathway for 1 suggested intriguing
oxidative rearrangement steps to form the five-membered lactone ring.