Diospyrone, a new coumarinylbinaphthoquinone from Diospyros canaliculata (Ebenaceae): structure and antimicrobial activity

Abstract

A new binaphthoquinone bearing two 4-hydroxy-5-methylcoumarin-3-yl units has been isolated from the stem bark of Diospyros canaliculata De Wildeman in addition to five known compounds: lupenone, betulinic acid, gerberinol, plumbagin and canaliculatin. Their structures were established on the basis of 1 D ( 1 H, 13 C and DEPT) and 2 D ( 1 H- 1 H COSY, HMQC and HMBC) NMR experiments. Some of the above compounds showed a significant antimicrobial activity against bacteria and yeasts. KEY WORDS : Diospyrone, Diospyros canaliculata , Ebenaceae, Bacteria, Yeasts Bull. Chem. Soc. Ethiop. 2005, 19(1), 81-88