Cuticular wax profiles of leaves of some traditionally used African Bignoniaceae

摘要

The cuticular waxes, obtained by chloroform extraction from the leaves of four African Bignoniaceae, Newbouldia laevis, Markhamia acuminata, Spathodea campanulata and Kigelia africana were analysed by GC-MS. The principal constituents were represented by a homologous series of n-alkanes (C-23-C-33), n-alcohols (C-18-C-30) and related carboxylic acids (C-16-C-36). For N. laevis and M. acuminata, ursolic and oleanolic acid were the most abundant wax components (52 and 60%, respectively), followed by the C-29, the C-31 and the C-33 n-alkanes. The predominant components of S. campanulata were n-alcohols (35%), with octacosanol and triacontanol as the most abundant ones, while K. africana is distinguished from these three members by the conspicuous absence of triterpenoic acids and the predominance of n-alkanes (70%) with hentriacontane and tritriacontane as the main representatives. Other notable constituents were sterols, albeit present in trace amounts. The wax profiles are discussed in terms of taxonomic characters.