Abstract: A new kaurane diterpenoid was isolated from the bark of Annona glabra Linn.Fifteen kg of bark of the plant was extracted with 95% EtOH for 3 times,each time for 2 h.The extract,which was suspended in water,was partitioned successively with petroleum ether,ethyl acetate and n-BuOH.Then the ethyl acetate fraction was subjected to silica gel column chromatography and recrystallization to afford compound 1. On the basis of chemical and spectral analysis,the structure was confirmed to be a kaurane diterpenoid,which is a novel compound,named 16α-hydroxy-17-acetoxy-ent-kauran-19-oic acid.

Key words: Annona glabra Linn., kaurane diterpenoid, 16α-hydroxy-17-acetoxy-ent-kauran-19-oic acid