Binding and potential antibiofilm activities of Amaranthus proteins against Candida albicans

In the present study evaluation of structural, thermal and antifungal properties of Amaranthus hypochondriacus laboratory protein isolate (ALMA) and commercially available Amaranthus protein dietary antidepressant (APGM) was done by differential scanning calorimetry (DSC), Fourier Transform Infrared (FTIR) and fluorescence spectroscopy and antibiofilm activities against Candida albicans. The results exhibited thermal stability and antioxidant activity for the isolates. Fluorescence measurements showed that they bind to human serum albumin through a static quenching mechanism, decreasing its fluorescence intensity. FTIR spectra showed amides I, II and III shifts, but it does not modify the structural and bioactive properties against C. albicans despite of its infections which is difficult to treat due to virulence expression and biofilm formation that protects of therapeutic drugs. Both isolates had the potential to assuage two virulence factors such as biofilm formation and yeast to hyphal transition of C. albicans. The biofilm inhibitory concentration of the protein isolates was determined to 10 and 30 μg mL⁻¹ with 50% inhibition, while morphogenic transition of the yeast leads to host tissue damage was significantly inhibited in spider medium and in vivo assay with zebrafish embryo. Inhibition of C. albicans biofilm by protein isolates was well compared with COMSTAT and XTT assay. The conformational changes in the proteins of investigated samples were determined by fluorescence after denaturation with 8 M urea and showed slight differences in comparison with the natural product. This is the first study to envisage the use of amaranth protein isolates to immunocompromised patients in their diet plan that can prevent C. albicans infections and help them in recovery. These isolates can be used as natural polymers in biomedical applications and edible films for health benefits.