Molecular and biochemical characterization of caffeine synthase and purine alkaloid concentration in guarana fruit

Convergent evolution of caffeine in plants by co-option of exapted ancestral enzymes

“…2C). Theobromine is reported from Paullinia tissues (37,38), which is consistent with the pathway shown in Fig. 2C, but no analyses have surveyed for the presence of intermediates such as 3-methylxanthine or others.…”

“…It is not yet clear which enzyme contributes to the low levels of caffeine accumulation in Theobroma, but this is not surprising, because its biosynthesis is reported to be very slow (35). In Paullinia, a third enzyme, PcCS, is reported to convert theobromine to caffeine (37) (Fig. 2C).…”

Research Article A proteomic approach to guarana seed and pericarp maturation.

“…This occurred because young tissues exhibit high energy demand and hence high mitochondrial activity (Thompson et al, 1998) due to the intense cell division at this stage (Salmona et al, 2008). Guarana seeds have high caffeine contents, which correspond to 2.5 to 5.8% of their dry weight (Schimpl et al, 2014). Although the present study did not identify the enzymes involved in caffeine synthesis, the xanthine skeleton of caffeine is derived from purine nucleotides (guanylate and adenylate) (Ashihara et al, 2008), and NDPK is involved in purine synthesis.…”

“…Although the present study did not identify the enzymes involved in caffeine synthesis, the xanthine skeleton of caffeine is derived from purine nucleotides (guanylate and adenylate) (Ashihara et al, 2008), and NDPK is involved in purine synthesis. As a purine alkaloid, caffeine is synthesized mainly in young leaves and immature fruit and then decreases gradually during the maturation of these organs (Ashihara et al, 2008;Schimpl et al, 2014). Schimpl et al (2014) evaluated the expression levels of caffeine synthase (Paullinia cupana Caffeine Synthase -PcCS) in different guarana cultivars including BRS Amazonas used in the present study.…”

“…Guarana is a dry dehiscent fruit that consists of a pericarp and an aril, which is an appendage rich in starch and seeds (1-3 seeds per fruit) (Poltronieri et al, 1995). The seed is the main commercial product of the plant due to its high caffeine content, which corresponds to 2.5 to 5.8% of the dry weight of the fruit, higher than that described for coffee (0.5 to 2.8%) (Schimpl et al, 2014). Other metabolites with medicinal properties include flavonoids, which have powerful antioxidant properties (Chirinos et al, 2010), catechins, which assist in weight loss (Murase et al, 2002), tannins, which have important antioxidant and antiinflammatory activities (Mattei et al, 1998;Tobi et al 2002), as well as others that contribute to the economic potential of this fruit.…”