Comprehensive evaluation of methylxanthines and phenolic compounds in Bahia’s guarana (Paullinia cupana), Brazil: implications for variety selection and by-product utilization

The State of Bahia, Brazil, stands as the predominant global producer of guarana, which is recognized for its seeds’ caffeine-rich composition. This study aimed to determine the concentrations of methylxanthines (theobromine, caffeine, and theophylline) and phenolic compounds (catechin and epicatechin) in guarana leaves, seeds, and pericarps collected from various producing cities in Bahia. High-performance liquid chromatography analysis was conducted, and the data set was subjected to principal component analysis (PCA) for evaluation. Theobromine and caffeine were found in all leaves and pericarps samples, where higher contents were quantified for theobromine. Caffeine was the major compound in seeds, followed by epicatechin and catechin. No statistical difference was observed for the average contents of caffeine in samples from different producing cities. PCA showed no clear guarana sample discrimination based on bioactive compound contents. This study holds substantial relevance for the valorization of guarana cultivation in Bahia, enabling the identification of cultivars harboring elevated levels of bioactive compounds, which can be selectively cloned to meet the demands of the consumer market. Furthermore, the investigation unveils the potential utilization of leaves and pericarps as sources for the extraction of theobromine and caffeine, exhibiting promising applications in the pharmaceutical industry.