Structural investigations and antibacterial, antifungal and anticancer studies on zinc salicylaldimine complexes

Abstract

Aim: Zinc salicylaldimines may act as multidrug agents.Results: Three zinc salicylaldimines C1-C3 and respective ligands HL¹-HL³ were examined for antimicrobial/anticancer drug action and C3 was structurally analyzed (tetrahedral, triclinic). Against two fungi, C1 inhibited Candida albicans with 12 mm (21 mm for amphotericin B). Among four bacteria, two ligands inhibited Staphylococcus aureus and Escherichia coli (9-10 mm), but the complexes inhibited all bacteria with 10-14 mm (21-26 mm for ampicillin). The half-maximal inhibitory concentrations for the ligands, complexes and doxorubicin were 195.5-310.7, 22.18-70.05 and 9.66 μM against cancerous MCF-7 cells and 186.4-199.9, 14.95-18.87 and 36.42 μM against normal BHK cells.Conclusion: The complexation produced pronounced enhancement in the ligand antimicrobial/anticancer activities, despite these activities are moderate comparing with standards.

Keywords: N and O chelation; anionic ligands; breast; diamagnetism; doxorubicin; kidney.

Figure 1.

Preparation scheme for the ligands and complexes.

Figure 2.

An ORTEP graphic of complex C3 with all H-atoms removed for clarity.

Figure 3.

Packing diagram of complex C3 along crystallographic b-axis.

Figure 4.

A plot displaying the effect by ligands HL¹–HL³ and complexes C1–C3 on four bacterial strains.

Figure 5.

A plot displaying the effect by ligands HL¹–HL³ and complexes C1–C3 on two fungal strains.

Figure 6.

Determined cytotoxicity data, due to ligands HL¹–HL³ and complexes C1–C3 (0–100 μg/ml), against cancer MCF-7 (left) and normal BHK (right) cells.