Water soluble chitosan conjugates with plant antioxidants and polyelectrolyte complexes on their basis

Water soluble conjugates of trimethyl chitosan (ChTM) and the low molecular mass chitosan (Ch30) with plant antioxidants – quercetin (Q) or dihydroquercetin (DHQ) – were synthesized. The carbodiimide-assisted reaction was used to couple Q or DHQ (previously modified by succinic anhydride) to the primary amino group of Ch30 or ChTM. The in vitro free-radical scavenging activity of conjugates derived was tested by their capacity to bleach the stable 1,1-diphenyl-2-picrylhydrazyl radical. All conjugates showed an antiradical activity higher than that of phenoxane, the known efficient antioxidant (sterically hindered phenol). The microparticles of complexes of the conjugates and Ch sulfate were proposed for pH-sensitive controlled release of antioxidants. The properties of the polyelectrolyte complexes with plant antioxidants would appear promising for per oral administration.