Química medicinal

Schiff Bases and their Transition Metal Complexes: A Review on Biological Facets

Abstract

Zahid Khan*

Schiff bases forms an important class of organic compounds the azomethine moiety present in these compounds renders them to exhibit a range of biological activities e.g. antimicrobial, antifungal antioxidant, α and β glucosidase and urease inhibition to name a few. The azomethine moiety is rich in electron density which is readily acceptable by electropositive transition metals that potentially opens up the possibility of a diverse array of metal-based candidate drug molecules. A huge number of such metal complexes are reported in the literature, this review presents a review of the literature examples and discussing various results primarily based on the role of azomethine involvement in chelation and the effect of other substitution in the close proximity with the azomethine group and their involvement in the complexation, furthermore the mechanism of biological action and reasons of pre and post complexation biological responses are also discussed. This review can provide a good starting point for people interested in exploring these compounds for any similar biological application in mind. The structural changes in the Schiff bases after chelation, the effect of substitutions, the involvement of azomethine group in the chelation and other important moieties in close proximity to the metal center after chelation can all act in deciding the overall biological activity, if such studies are performed for a series of homologous compounds, the results can become very valuable in identifying possible lead compounds. All examples presented in this review primarily focuses on a new subclass of compounds called bis Schiff bases, and they are so called because of the presence of two azomethine groups in their structures.