Zn (II) complex with vanillin derived Schiff base: antifungal, antibacterial, antioxidant and anticholinesterase activities

To synthesize and characterize a Schiff base derived from vanillin and tris(hydroxymethyl)aminomethane (VTRIS) and the Zinc (II) complex [Zn(VTRIS)₂](CH₃COO)₂. VTRIS and the Zn (II) complex were synthesized through condensation and complexation reactions, respectively. Structures were confirmed by electron spectroscopy in the UV-Vis, FT-IR and NMR regions. Toxicity was evaluated in Artemia salina, antimicrobial activity was evaluated by microdilution assay, ABTS and DPPH methods were used for antioxidant effect and the anticholinesterase potential was investigated. VTRIS and the complex showed low toxicity in <i>Artemia salina</i> (LC₅₀ = 698.56 and 543.88, respectively). VTRIS did not show antifungal or antibacterial activity, but the complex showed MICs ranging from 32 to 128 μg/mL against <i>Cryptococcus neoformans</i> and <i>Candida</i> spp. and 512 μg/mL against <i>Staphylococcus aureus</i>, demonstrating an antimicrobial effect improvement after coordination to the metal center. VTRIS and the complex showed excellent results as antioxidant molecules, and the complex presented lower values than the standard quercetin in the ABTS method (IC₅₀ = 1.08 and 1.63 μg/mL, respectively). VTRIS and the complex showed anticholinesterase potential of 1.93 and 1.83 μg/mL. Zn complexation potentiates VTRIS, and this compound exhibits promising antimicrobial, antioxidant, and anticholinesterase activities at nontoxic concentrations. The number of novel medicines launched on the market is decreasing over the years, making the available therapy options limited, especially in diseases where there may be therapeutic failure due to several factors, such as antimicrobial resistance. The union of metals such as zinc to natural derived compounds has shown potential biological activity, and this kind of strategie can be a great option to overtake some of these therapeutic problems. So, we chemically united the zinc to a vaniline compound and we found that this new drug can be a great therapeutic option presenting many biological activities, such as killing fungal and bacteria that are considered a concern for medicine, in addition to shown antioxidant effect and improving the neurological activity by blocking an important molecule involved in this process called cholinesterase. A new Schiff base derived from vanillin and Zn (II) complex has been synthesized and characterized.The Schiff base and the Zn (II) complex showed no toxicities at the concentrations tested.The Zn (II) complex showed better results in antifungal, antioxidant, and anticholinesterase activities compared to the Schiff base. A new Schiff base derived from vanillin and Zn (II) complex has been synthesized and characterized. The Schiff base and the Zn (II) complex showed no toxicities at the concentrations tested. The Zn (II) complex showed better results in antifungal, antioxidant, and anticholinesterase activities compared to the Schiff base.