Two new sesquiterpene lactones from Ceiba pentandra.

Two new sesquiterpene lactones showing moderate antimicrobial activity have been isolated from the root bark of Ceiba pentandra (Bombacaceae) in addition to the known compounds 8-formyl-7-hydroxy-5-isopropyl-2-methoxy-3-methyl-1,4-naphthaquinone+ ++ [1], and 7-hydroxycadalene [2]. The new compounds were characterized as 2,7-dimethoxy-5-isopropyl-3-methyl-8,1-naphthalene carbolactone [3] and 2-hydroxy-5-isopropyl-7-methoxy-3-methyl-8,1-naphthalene carbolactone [4] by chemical and spectroscopic studies.