Phenolic acids and flavonoids of Theobroma cacao L.; separation and identification by paper chromatography.

Previous investigations on the phenolic constituents of Theobroma cacao L. have been largely limited to studies on the polyphenols of the ripe bean (Forsyth, 1952, 1955; Forsyth & Quesnel, 1957), which have been shown to be of major importance in determining the taste characteristics of processed cacao. Studies are now being pursued in this Laboratory on the nature of the factors determining the chemical composition of the bean at maturity with particular reference to the phenolic constituents of the cotyledons. The physical and biochemical factors determining the level of polyphenols other than anthocyanins in vegetative and reproductive organs of the green plant are largely unknown, although it has recently been shown by Hillis & Swain (1957) that illumination is an important factor in the formation of the leaf leucocyanidins of Prunus domastica var. victoria. Other of our current investigations are concerned with the possible role of the phenols in the mechanism of disease resistance of T. cacao, evidence having been obtained of an intense metabolic activity involving the host polyphenols of T. cacao tissue after invasion by Mara8mius pernicio8u (L. A. Griffiths, unpublished work). For both these projects a systematic investigation of the phenolic constituents of both vegetative and reproductive tissues was a necessary preliminary and the results obtained are presented in this paper. Although there are many reports in the literature describing the sporadic occurrence of phenolic compounds in various plant materials, a study of the distribution and interrelations of this class of compound throughout the vegetative and reproductive structures of a single species of green plant does not appear to have been previously undertaken. In this survey of the phenolic constituents of T. cacao, both methanolic and acid-hydrolysed extracts have been examined by paper chromatography.