Lasiodiplodiapyrones A and B, Pyrone–Preussomerin Adducts with Highly Strained Polycyclic Ring Systems from <i>Lasiodiplodia pseudotheobromae</i>
Liang Yu, Qin Li, Yongqi Li, Yuyi Zheng, Yong Shen, Haojie Yang, Yuling Lu, Junjun Liu, Qun Zhou, Dongyan Li, Weiguang Sun, Hucheng Zhu, Chunmei Chen, Yonghui Zhang
Abstract
Lasiodiplodiapyrones A and B ( 1 and 2 ), two new preussomerin derivatives, possessing an unexpected 6-methyl-4 H -furo[3,2- c ]pyran-4-one moiety and a highly functionalized conjoint and complicated polycyclic ring system, along with two known congeners ( 3 and 4 ), were isolated from the fungus Lasiodiplodia pseudotheobromae . Their structures including absolute configurations were determined by spectroscopic analyses, Mosher’s method, and ECD calculations. A biosynthetic pathway was proposed to explain the origin of lasiodiplodiapyrones A and B as well as their relationship with preussomerins. Compounds 1 – 4 showed suppressive effects on the production of NO with IC 50 values of 4.8 ± 0.3, 8.5 ± 1.1, 5.9 ± 0.8, and 12.8 ± 1.3 μM, respectively.