Antibacterial sideroxylonals and loxophlebal A from Eucalyptus loxophleba foliage.

Loxophlebal A, a new antibacterial formylated phloroglucinol was isolated from the mother liquor obtained after separation of sideroxylonals from the chloroform-methanol extract of leaves of Eucalyptus loxophleba ssp lissophloia. The structure of loxophlebal A was determined to be 3-desformyl sideroxylonal A by spectroscopic methods including 1D- and 2D-NMR. The stereochemistry of loxophlebal A was determined by chemical correlation with sideroxylonal A. This article also reports an efficient, simple and economic method for large scale isolation of sideroxylonals in a purity of >90% from the leaves of Eucalyptus loxophleba ssp lissophloia.