Joannesialactone and other compounds from Joannesia princeps

The novel natural products joannesialactone, (-)-alpha-barbatenal, 4-hydroxy-10-epirotundone, and the E- and Z-isomers of 2-(4-hydroxyphenyl)ethenyl-alpha-L-rhamnopyranoside and the 3-O-rhamnosides of the dimeric proanthocyanidins afzelechin-(4 alpha --> 8)-epiafzelechin-3-O-vanillate, afzelechin-(4 alpha --> 8)-epicatechin-3-O-vanillate, afzelechin-(4 alpha --> 8)-epiafzelechin-3-O-syringate and afzelechin-(4 alpha --> S)-epicatechin-3-O-syringate have been isolated from the root bark of Joannesia princeps, along with the antibiotic principle cyperenal, the colouring matter assufulvenal, curcusones C and D and 16 further known compounds. Structure determination was achieved mainly by spectroscopic studies and/or by comparison with authentic substances. (C) 1997 Elsevier Science Ltd.