The composition of Eucalyptus and some other leaf waxes

Abstract

Many Eucalyptus waxes contain as major components long-chain β-diketones, which may be readily separated from the rest of the wax as insoluble copper complexes. The most commonly occurring β-diketone is n-tritriacontan-16,18-dione, but in two species, Eucalyptus risdoni and E. coccifera, β-diketones of shorter chain length predominate. From the waxes of several Eucalyptus species a new flavone, 5-hydroxy- 4',7-dimethoxy-6,8-dimethylflavone, and a new triterpene, 11,l2-dehydroursolic lactone acetate, have been isolated. Gas chromatography has been used to determine the chain length distribution of β-diketones, hydrocarbons, and esters from several waxes. The esterified alcohols of Eucalyptus globulus and E. risdoni belong to two series-long-chain n-alkan-1-ols of predominantly even carbon number, and n-alkan-2-ols of medium chain length and predominantly uneven carbon number (n-C₉, n-C₁₁, n-C₁₃, and n-C₁₅).