Caracterização química, composição centesimal e avaliação citotóxica dos frutos de Theobroma bicolor, Theobroma subincanum e Theobroma sylvestre

Abstract

Humid tropical forests, such as the Amazon, harbor countless plant species of interest to the food and pharmaceutical industries, with the potential to drive the region's scientific, technological, and economic development. However, species such as Theobroma bicolor (macambo), Theobroma subincanum (cupuí), and Theobroma sylvestre (blue cacao), belonging to the Malvaceae family and classified as Unconventional Food Plants (UFPs), remain underexplored and require detailed studies on their chemical composition and nutritional value. In this context, this study aimed to investigate the proximate composition, chemical profile of bioactive compounds, and cytotoxic potential of the fruits (peels, pulps, and seeds) of Amazonian Theobroma species. Extracts of blue cacao, cupuí, and macambo were obtained by cold maceration in an ultrasonic bath. The proximate composition (moisture, proteins, lipids, carbohydrates, and ash) was determined for the different parts of the fresh fruits. The chemical profile was evaluated using spectroscopic and chromatographic techniques, while cytotoxicity assays were performed against the A549 and HCT-8 tumor cell lines and HUVEC endothelial cells. The fruit of T. sylvestre (blue cacao) exhibited physicochemical characteristics consistent with cocoa-derived products, with the seeds standing out for their high protein and carbohydrate contents and energy value (144.13 kcal/100 g). A total of 23 metabolites were identified, including flavonoids and methylxanthines, four of which were reported for the first time in the genus Theobroma: 3-methyl-1-butanol-pentosyl-hexoside-1, secoisolariciresinol-9′-O-β-D-glucopyranoside, a furanoid diterpenoid glycoside, and syringin. The extracts exhibited moderate cytotoxicity and relevant antiproliferative activity against the A549, HCT-8, and HUVEC cell lines. In T. subincanum (cupuí), the seeds showed high protein and carbohydrate contents and a high energy value (360.69 kcal/100 g). Lipid profile analysis revealed the presence of fatty acids such as palmitic and linoleic acids in the different parts of the fruit, as well as elaidic acid in the pulp and peel. Six constituents were identified, including tryptophan, the alkaloid theacrine, and flavonoids such as epicatechin, clovamide, and luteolin, highlighting the chemical similarity among species within the genus. For T. bicolor (macambo), proximate composition analysis indicated that the seeds had a high energy value (377.40 kcal/100 g) and were predominantly composed of carbohydrates, whereas the lipid profile showed high levels of saturated fatty acids, particularly derivatives of palmitic and stearic acids. Chemical characterization revealed compounds such as oleic acid, formic acid, tryptophan, and the methylxanthines theophylline and theobromine. In the cytotoxicity assays, the extracts demonstrated moderate activity and antiproliferative effects, with the greatest inhibition of cell growth observed for the peel extracts. These findings demonstrate that the studied species possess significant nutritional and bioactive potential, representing promising sources of compounds with antioxidant and antiproliferative properties. Therefore, these contributions expand the phytochemical knowledge of the genus Theobroma and highlight the potential for the sustainable use of these Amazonian species in the development of functional foods, nutraceutical ingredients, and biotechnological applications.