Synthesis, characterization, and antifungal activity of nystatingum arabic conjugates

Abstract

Nystatin, a polyene tetraene antibiotic widely used in the treatment of mycoses, was coupled with oxidized polysaccharide gum Arabic, by forming Schiff base structures between amine groups of antibiotics and aldehyde groups of modified carbohydrate. Imine conjugates synthesized in this way were reduced with sodium borohydride to secondary amines. Two imine and two amine conjugates were obtained with different nystatin content. The conjugates were characterized by UVVis, FTIR, 1H NMR spectroscopy, and thermogravimetric analysis. Solubility in water, unlike nystatin, and significant activity against Candida albicans and Aspergillus niger with minimum inhibitory concentrations in range of 3.1256.25 mu g mL-1 and 6.2525 mu g mL-1, respectively, indicate that the chemical integrity and the biological function of these compounds were retained. A comparison of stability of the conjugates in the dry form, solution and under different pH values showed that the conjugates exhibited better stability than pure drug.