Bioactivities and Phytochemical Profiling of Trigynaea axilliflora from Brazil

Brazil is a country with the greatest biodiversity in the world, but much of it is still largely unexplored. Trigynaea axilliflora (Annonaceae) is a Brazilian plant species that has not been previously studied. This research aimed to characterize the chemical constituents and evaluate the biological activities of the extract, fractions and isolated compounds. Xylopine, a major compound isolated from this extract, is an aporphine alkaloid and a chemotaxonomic marker of this family, whose structure was confirmed by ¹H/¹³C NMR and HRESIMS. HPLC-UV-ESI-qTOF dereplication indicated that xylopine and seven other aporphine alkaloids were present in the crude extract. A solvent washing procedure allowed the recovery of 138 mg of xylopine, with a yield of 13.8% (138 mg/g crude extract) and 95% purity by HPLC-DAD. Cytotoxicity by the MTT assay showed that xylopine was active against MG-63 osteosarcoma cells (IC₅₀ = 5.5 μg/mL), with a selectivity index (SI = 0.63) indicating a favorable selectivity compared to doxorubicin (SI = 0.22). Antibacterial assays demonstrated the inhibition of Staphylococcus aureus and Escherichia coli by the ethanolic extract and chloroform fraction (MIC 125-500 μg/mL), as well as by xylopine (MIC 62.5 μg/mL for S. aureus and 31.2 μg/mL for E. coli). To evaluate antinociceptive activity, the formalin test was used, and both the ethanolic extract and xylopine significantly reduced nociceptive behavior during the inflammatory phase from 123.8 ± 13.7 s (100%) to 71.3 ± 10.2 s (57.5%) and 1.3 ± 0.4 s (1%), respectively, at doses of 30 mg/kg. In silico pharmacokinetic analysis using SwissADME predicted favorable drug-likeness and oral bioavailability for xylopine, supporting its potential as a drug candidate. This study presents the first report on the chemical profile and bioactivities of T. axilliflora, suggesting it as a possible natural source of xylopine. This finding highlights the importance of phytochemical and pharmacological research in understanding Brazil's understudied flora.