Valorization of the peel and husk of guaraná ( <i>Paullinia cupana</i> ): oil extraction, chemical composition, cytotoxicity, and antitumor potential

Abstract Guaraná ( Paullinia cupana ) is a fruit native to the Amazon region. Due to its widespread use, primarily in beverages, its production has grown over the years. The seed is the only commercially valuable part of the fruit so the guaraná production chain generates byproducts, including peel, husk, and spent seed. Both the husk and peel can be used as raw materials for oil extraction. The use of new oil sources is important for the food and pharmaceutical industries, as their constituents can be used in various applications. This study aimed to extract oil from guaraná byproducts (peel and husk) using Soxhlet extraction, characterize it by gas chromatography–mass spectrometry (GC–MS), and evaluate its biological potential through cytotoxicity and antitumor assays. The peel oil mainly contained the compound 8‐androsten‐3‐ol, 17‐(2‐methylallyl)‐4,4,14‐trimethyl, followed by cycloartenol and (E)‐14 α ‐methyl‐5 α ‐ergosta‐8,23‐dien‐3 β ‐ol. In husk oil, the main compounds were 7‐octadecenoic acid methyl ester and palmitic acid methyl ester. In L929 cells, peel oil showed cytotoxicity at concentrations above 250 μg mL −1 , and husk oil at concentrations above 100 μg mL −1 . Regarding antitumor activity, at concentrations where the oils did not exhibit cytotoxicity, husk oil reduced metabolic activity by up to 21% and peel oil by up to 67% in C6 cells. For A549 cells, metabolic activity decreased to approximately 65% for peel oil and 76% for husk oil; both oils showed a decrease in GL261 cell activity to approximately 50%.