FATE OF PHENYLALANINE-C14AND CINNAMIC ACID-C14IN MALUS IN RELATION TO PHLORIDZIN SYNTHESIS

Abstract

Both phenylalanine-C14 and cinnamic acid-C14 were utilized in the synthesis of phloridzin-C14 by Malus leaf disks, although this synthesis could be demonstrated only with young leaves. Two compounds, tentatively identified as a cinnamyl-glucose ester and a p-coumaryl-glucose ester, were formed in appreciable quantities when either phenylalanine or cinnamic acid was administered. Smaller amounts of p-coumaryl-quinic and chlorogenic acids were also synthesized. Although radioactive p-coumaric acid was identified in each experiment, phloretic acid was never labeled. The significance of these results in relation to the biogenesis of phloridzin in Malus is discussed.