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 Artemia salina (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 Cryptococcus neoformans and Candida spp. and 512 μg/mL against Staphylococcus aureus, 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.