Caffeine and theobromine analysis of Paullinia yoco, a vine harvested by indigenous peoples of the upper Amazon.

Paullinia yoco R.E. Schult. & Killip (Sapindaceae) or 'yoco', is a liana (a woody vine) used traditionally by indigenous peoples of the upper Amazon region as a stimulating beverage, because it contains both caffeine and theobromine. However, as the wild plants become increasingly rare and hard to find because of permanent settlement within a much-reduced territory, there is growing interest among indigenous tribes to learn how to successfully cultivate it for community consumption and potentially as a cash crop. To date, there has been very little research conducted on the stimulant chemical composition of the liana and biochemical variation within- and between plants. This paper provides the results of chemical (high-performance liquid chromatography) analysis of caffeine and theobromine concentrations of multiple samples of phloem and leaf material from 18 Paullinia yoco lianas. Caffeine values ranged from 0.1% to 3.6% with a significantly higher amount in the stem phloem material than the leaf material, and there was a positive linear correlation between stem diameter and caffeine concentration (% dry weight). Although the highest theobromine level was found in leaf material (1.8%), overall there was no significant difference between phloem and leaf material, and no correlation between stem diameter and theobromine concentration. Finally, we found a significant amount of variance of both caffeine and theobromine between individual plants. These results are important, first because they shed light on the apparently conflicting previous reports on P. yoco caffeine and theobromine content; and second, they provide important clues about the phytochemical architecture of P. yoco which in turn has important implications for the design of a cultivation strategy for local indigenous communities to potentially produce a yet-to-be domesticated plant of substantial market potential.