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.

Stable polyanhydride synthesized from sebacic acid and ricinoleic acid.

Poly(anhydride) are unstable and prone to hydrolytic degradation and depolymerisation via anhydride interchange. They are stored at -20°C, packed under inert atmosphere until use. We synthesized a new poly(anhydride) from ricinoleic (RA) and sebacic (SA) acid with alternating ester-anhydride structure that is stable at 25°C for over 18months. The copolymer is also stable in chloroform solution and under γ-irradiation. The polymer hydrolyses through anhydride cleavage lasting ~7days to form oligoesters, which are stable for >30days. The release of gentamycin from the synthesized alternate polymer matrix is sustained compared to the random copolymer.

Alternating Poly(ester-anhydride) by Insertion Polycondensation.

We report on a synthetic method where polyanhydride is used as starting material and the ester monomers are inserted through complete esterification, leading to an alternating ester-anhydride copolymer. The molar ratio of ricinoleic acid (RA) and sebacic acid (SA) was optimized until polysebacic acid is completely converted to carboxylic acid-terminated RA-SA and RA-SA-RA ester-dicarboxylic acids. These dimers and trimers were activated with acetic anhydride, polymerized under heat and vacuum to yield alternating RA-SA copolymer. The resulting alternating poly(ester-anhydride) have the RA at regular intervals. The regular occurrences of RA side chains prevent anhydride interchange, enhancing hydrolytic stability, which allows storage of the polymer at room temperature.