Sesquiterpene lactones. XXXI. New guaianolides in Centaurea bella Trautv. and Centaurea adjarica Alb.

Nine new guaianolides. I of which are chlorinated, were isolated from the dried, above-ground parts of Centaurea bella Trautv. They are: cebellin A. B, C, D, E. F, G, H and 1. l he known guaianolides centaurepensin and repdiolide were also found. The occurrence of repin. acroptillin and janerin was confirmed. Cebellin F. G. I and repin. acroptillin and janerin were chromatographically shown to occur in Centaurea adjarica Alb