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Bauhinia ungulata L. species, belongs to the genus Bauhinia, popularly known as pata de vaca, is among the species of medicinal employ in Brazil, used to treat diabetes. The aim of this study was to characterize the chemical composition, antimicrobial activity, toxicity on Artemia salina and acetylcholinesterase enzyme inhibition by essential oil from B. ungulata L. The chromatographic analysis revealed 18 components, the majority were the β-caryophyllene (15.9%), caryophyllene oxide (9.2%), α-humulene (8.1%), epi-γ-eudesmol (7.5%), α-bisabolol (4.7%), copaene (3.5%), nerolidol (3.3%), α-bisabolol oxide B (2.5%), spathulenol (2.1%). The essential oil showed high toxicity compared to the tests with Artemia salina and inhibited 95.96%±0.62 of the acetylcholinesterase enzyme. The microorganisms show antimicrobial inhibition with Candida albicans (85%), Bacillus cereus (65.5%) and Staphylococcus aureus (66.4%), Salmonella typhimurium (68.7%) and Citrobacter freundii (46.1%). The oil showed great potential when tested in bioassays.

Tyrosine kinase inhibitors (TKIs) are antitumor compounds that prevent the phosphorylation of proteins in a biological environment. However, the multitarget performance of TKIs promotes them as possible candidates for drug repositioning. In this work, interaction and inhibition studies through spectroscopic and computational techniques to evaluate the binding effectiveness of lapatinib and pazopanib TKIs to acetylcholinesterase (AChE) are reported. The results indicated potent inhibition at the μM level. The types of inhibition were identified, with pazopanib acting through non-competitive inhibition and lapatinib through acompetitive inhibition. The fluorescence suppression studies indicate a static mechanism for lapatinib−AChE and pazopanib−AChE systems, with a binding constant in the order of 10 5 M −1 . The obtained thermodynamic parameters reveal interactions driven by van der Waals forces and hydrogen bonds in the lapatinib−AChE system (ΔH°and ΔS°< 0). In contrast, the pazopanib−AChE system shows positive ΔH°and ΔS°, characteristic of hydrophobic interactions. The Foster resonance energy transfer study supports the fluorescence studies performed. The 3D fluorescence studies suggest changes in the microenvironment of the tryptophan and tyrosine residues of the protein in contact with lapatinib and pazopanib. The results suggest effective inhibition and moderate interaction of the drugs with AChE, making them interesting for conducting more in-depth repositioning studies as AChE inhibitors.