Chemical investigation of ceylonese plants. Part I. Extractives of Calophyllum calaba L. and Calophyllum bracteatum Thw. (Guttiferae)

Abstract

The bark and timber extracts of C. calaba L. and C. bracteatum Thw. have been studied. A new di-isoprenylated xanthone, named calabaxanthone, isolated from the barks of both species has been shown to be 5-hydroxy-8-methoxy-2,2-dimethyl-7-(3-methylbut-2-enyl)-2H,6H-pyrano[3,2-b]xanthen-6-one (II). The bark extracts of both species have yielded taraxerol (Ia) and taraxerone (Ib). The bark extracts of C. bracteatum Thw. have also yielded calophyllolide (XI). The timber extracts of C. calaba L. have given a hitherto unknown xanthone 1,8-dimethoxy-2-hydroxyxanthone (VII), eight other known xanthones, β-sitosterol, and stigmasterol. The timber extracts of C. bracteatum Thw. have given two new xanthones 1,3,5-trihydroxy-2-methoxyxanthone (XII) and 1,8-dihydroxy-3,5,7-trimethoxyxanthone (XVI), four other known xanthones, betulinic acid, β-sitosterol, and stigmasterol. Structures of the new xanthones have been elucidated.