Antioxidant properties of yeast (1→3)-β--glucan studied by electron paramagnetic resonance spectroscopy and its activity in the adjuvant arthritis

Radical-scavenging activity of the water-soluble derivative obtained from cell wall of the baker's yeast Saccharomyces cerevisiae was investigated using the technique of electron paramagnetic resonance. The experiments involved a study of the scavenging activity of carboxymethyl (1→3)-β-d-glucan (CMG) towards the radicals formed in the thermally initiated decomposition of potassium persulfate, hydrogen peroxide, or 2,2′-azo-bis(2-amidinopropane)-dihydrochloride in aqueous solutions using spin trapping as an indicative technique. In the absence of glucan, high intensity spectra of generated free radicals in the form of their adducts with 5,5-dimethylpyrroline-N-oxide were observed. Addition of CMG resulted in concentration-dependent substantial decrease of spectral intensities of adducts as a result of competition of CMG in the scavenging of reactive radicals formed. In the in vivo experiments involving administration of CMG to rats with experimentally induced adjuvant arthritis (AA) a substantial decline of the level of plasmatic carbonyls, a parameter indicating oxidative tissue damage during the progress of arthritic diseases, was observed. We assume that radical-scavenging properties of CMG can be responsible for its antioxidant activity in the AA model, suggesting possible application of the yeast glucan derivatives in the treatment of arthritis.