Content and Distribution of Erythroxylum coca Leaf Alkaloids

Abstract

Fully expanded leaves of Erythroxylum coca var. coca Lam. (Erythroxylaceae) 35-70-d-old were harvested from 21-month-old plants grown under greenhouse conditions. Each harvested leaf was placed on a plexiglass silhouette according to its dimensions and divided into four primary sections (petiole, base, mid and anterior) and three subsections (lamina periphery, false mid-rib, and true mid-rib) to determine the distribution and content of hygrine, cuscohygrine, trans-cinnamoylcocaine, cis -cinnamoylcocaine, tropacocaine, tropinone, methyl ecgonine and cocaine. The leaf sub-sections and petiole were extracted and analysed for alkaloid content (%) by HPLC (cocaine alkaloid only) gas chromatography and GC/MS. Cocaine, methyl ecgonine and hygrine were highest in the lamina periphery with a content of 0·48, 0·46 and 0·32%, respectively. Trans-cinnamoylcocaine was pre-eminent of the cinnamoylcocaines and was most abundant in the petiole at a content of 0·24%. Cis-cinnamoylcocaine, tropinone, cuscohygrine and tropacocaine were ubiquitously distributed throughout the leaf where the average contents were 0·14, 0·004, 0·16 and 0·04%, respectively.