Diplopterys pubipetala (Malpighiaceae): Insights into Antioxidant, Antibacterial, and Antifungal Activities with Chemical Composition Analysis via UHPLC-MS/MS and GC/MS

<i>Diplopterys pubipetala</i> (Malpighiaceae) is a liana native to the Brazilian Cerrado biome, traditionally used in Ayahuasca preparations. Despite its cultural importance, research on its chemical composition and biological activities, which may have therapeutic potential, is limited. This study investigated the volatile and non-volatile secondary metabolites of <i>D. pubipetala</i> leaves, their antioxidant capacity, and their antibacterial and antifungal activities. Volatile compounds were identified using gas chromatography-mass spectrometry (GC-MS) coupled to solid-phase microextraction (SPME), while non-volatile compounds were annotated using UHPLC-MS/MS-ESI-Q-TOF. Antioxidant capacity was evaluated by DPPH assay, and antimicrobial activity was assessed in vitro against <i>Staphylococcus aureus</i>, <i>Escherichia coli</i>, <i>Pseudomonas aeruginosa</i>, and <i>Candida</i> species (<i>C. albicans</i>, <i>C. tropicalis</i>, <i>C. glabrata</i>). GC-MS analysis revealed 25 predominant volatile compounds, including ethyl dodecanoate, ethyl tetradecanoate, nonanoic acid, and 5-methylhexan-2-one, with documented antifungal, antioxidant, and antimicrobial activities. The crude extract and ethyl acetate fraction showed strong antioxidant capacity (EC₅₀ 9.83 µg/mL and 6.42 µg/mL, respectively), and antifungal effects were observed against <i>Candida</i> species. This study provides the first comprehensive investigation of the antioxidant capacity and antibacterial and antifungal activities of <i>D. pubipetala</i>, together with a detailed chemical profile of its volatile compounds.