Triterpenes from <i>Warszewiczia coccinea</i> (Rubiaceae) as Inhibitors of Acetylcholinesterase

Abstract

Seventy-six plant extracts from the Panamanian flora have been screened for acetylcholinesterase (AChE) inhibitors by thin-layer chromatography (TLC) bioautography. The most promising extracts with AChE inhibitory and free radical scavenging activities at 100 μg were those of Tabernaemontana panamensis (Markgr., Boiteau &amp; L. Allorge) Leeuwenb., Pentagonia macrophylla Benth., and Warszewiczia coccinea (Vahl) Klotzsch. Bioguided fractionation of W. coccinea stem extract afforded two triterpenes, 3β,6β,19α-trihydroxy-urs-12-en-28-oic acid (1) and 3β,6β-dihydroxy-olean-12-en-28-oic acid (sumaresinolic acid) (2), with AChE inhibitory activity. Their structures were determined by spectroscopic methods. This is the first report of these bioactive triterpenes in W. coccinea.