Gypmacrophin A, a rare pentacyclic sesterterpenoid, together with three depsides, functioned as new chemical evidence for gypsoplaca macrophylla (Zahlbr.) timdal identification

Abstract

The phytochemical investigation on 1 g of materials from Gypsoplaca macrophylla (Zahlbr.) Timdal resulted in the discovery of gypmacrophin A, a rare pentacyclic sesterterpenoid; brialmontin III, a new polysubstituted depside and two known ones, brialmontins I and II. The structure and absolute configurations of gypmacrophin A were elucidated by spectroscopic analyses and computational methods. Gypmacrophin A showed weak inhibition of AchE with an IC50 value of 32.03 μM. The four compounds provided new chemical evidence for G. macrophylla identification.