Shearinines D–K, new indole triterpenoids from an endophytic Penicillium sp. (strain HKI0459) with blocking activity on large-conductance calcium-activated potassium channels

• DOI: 10.1016/j.tet.2006.10.050
• Publication Date: 2006-11-16T02:28:59Z
• Authors: Minjuan Xu; Guido Gessner; Ingrid Groth; Corinna Lange; Arnulf Christner; Torsten Bruhn; Zhiwei Deng; Xiang Li; Stefan H. Heinemann; Susanne Grabley; Gerhard Bringmann; Isabel Sattler; Wenhan Lin
• Keywords: 01 natural sciences; 0104 chemical sciences

Abstract A chemical examination of the endophytic fungus Penicillium sp. isolated from the mangrove plant Aegiceras corniculatum resulted in the isolation and characterization of eight new indole triterpenes named shearinines D–K (1–8), along with shearinine A (9), paspalitrem A (10), and paspaline (11). Their stereostructures were determined by extensive spectroscopic data analyses and quantum chemical circular dichroism calculations. The biosynthetic relationship of all 11 alkaloids is suggested. Shearinines D (1), E (2), and (with reduced potency) G (4) exhibit significant in vitro blocking activity on large-conductance calcium-activated potassium channels.