Definition: Cyclic esters of hydroxy carboxylic acids, containing a 1-oxacycloalkan-2-one structure. Large cyclic lactones of over a dozen atoms are MACROLIDES.
pyran-2-ones: index PYRONES + LACTONES but BENZOPYRAN-2-ONES is available; for cyclic lactones over 12 atoms consider MACROLIDES
ginkgolide B [ BN 52021,BN-52021,Ginkolide B,ginkgolide B, (1beta)-isomer ] a PAF-receptor antagonist; isolated from Ginkgo biloba tree; RN given refers to (1alpha)-isomer; the most active ginkgolide at antagonizing PAF receptors