Epicuticular Leaf Flavonoids from Eucalyptus Species and from Kalmia latifolia

Abstract

Abstract In young plants of Eucalyptus globulus the leaves are covered with a whitish epicuticular layer. This leaf wax contains small amounts of C-methylated flavones as aglycones. A novel flavone has now been identified as 5,4′-dihydroxy, 7-methoxy, 6-methyl-flavone (8-desmethyl-sideroxylin). Another minor external flavone is chrysin. On leaves of E. sieberi the flavanone pinocembrin could be detected. It is shown that the four C-methylated flavones, eucalyptin, 8-desmethyl-eucalyptin, sideroxylin, and 8-desmethyl-sideroxylin are present in the leaf wax of 8 species analyzed. The same flavones are present on leaves of Kalmia latifolia.