A phytochemical study of ilex and betula species

Abstract

A phytochemical study of the outer bark of native common holly (Ilex aquifolium), led to the isolation and identification of nine novel fatty acid esters of the pentacyclic triterpene a-amyrin. These compounds were the oleate, linoleate, hepladcctrienoate, decanoate, myristate, pentadecanoate, palmitate, heptadecanoate and stearate esters of the triterpene. Studies on the outer bark of native birch (Betula ubescens) led to the isolation and identification of the pentacyclic triterpenes betulin and lupeol. Oxidation of belulin led to the formation of betulonic acid, which in turn was reduced and acetylated to yield betulinic monoacetate. Both of these derivatives are naturally occurring pentacyclic triterpenoids. The barks of two non-native or exotic species of birch (Betula ermanii and Betula papyrifera) were also investigated and this study resulted in the isolation of two further pentacyclic triterpenes; oleanolic acid and oleanolic monoacetate. The molecular structures of these compounds and their synthetic derivatives were elucidated using the following modern chemical and spectroscopic methods and techniques; 13C & JH NMR, FT-IR and GC/MS. In addition, an extensive literature review for the medicinal and commercial applications of the triterpenoids was undertaken.