A novel, simple, and cheap method to synthesize antioxidant-protein conjugates by grafting reaction was developedemploying a hydrogen peroxide-ascorbic acid pair as radical initiator system. Our challenge was to covalentlybind molecules with tested antioxidant activity, as gallic acid (GA) and catechin (CT) to a biomacromolecule, asgelatin, extensively used in the pharmaceutical, cosmetic, and food industry. In this way, two gelatin conjugates,bearing GA and CT covalently bounded to a side chain of protein, were synthesized. Calorimetric, UV-vis, andfluorescence analyses were performed to verify the covalent bond between antioxidant molecules and gelatin,and the antioxidant activity of conjugates was compared to that of a control polymer submitted to the samereaction conditions without antioxidant molecule. The ability of synthesized materials to inhibit 2,2′-diphenyl-1-picrylhydrazyl, hydroxyl radicals, and linoneic acid peroxidation was determined and, to well characterizedantioxidant properties of grafted biomacromolecules, disposable phenolic equivalents and total antioxidant activitywere calculated. The conjugates showed a good antioxidant activity, confirming the efficiency of the syntheticstrategy proposed in this paper. The results clearly showed that antioxidant moieties covalently bounded to anatural polymer allow to introduce in the macromolecule peculiar features for specific industrial applications.
A novel, simple, and cheap method to synthesize antioxidant-protein conjugates by grafting reaction was developedemploying a hydrogen peroxide-ascorbic acid pair as radical initiator system. Our challenge was to covalentlybind molecules with tested antioxidant activity, as gallic acid (GA) and catechin (CT) to a biomacromolecule, asgelatin, extensively used in the pharmaceutical, cosmetic, and food industry. In this way, two gelatin conjugates,bearing GA and CT covalently bounded to a side chain of protein, were synthesized. Calorimetric, UV-vis, andfluorescence analyses were performed to verify the covalent bond between antioxidant molecules and gelatin,and the antioxidant activity of conjugates was compared to that of a control polymer submitted to the samereaction conditions without antioxidant molecule. The ability of synthesized materials to inhibit 2,2′-diphenyl-1-picrylhydrazyl, hydroxyl radicals, and linoneic acid peroxidation was determined and, to well characterizedantioxidant properties of grafted biomacromolecules, disposable phenolic equivalents and total antioxidant activitywere calculated. The conjugates showed a good antioxidant activity, confirming the efficiency of the syntheticstrategy proposed in this paper. The results clearly showed that antioxidant moieties covalently bounded to anatural polymer allow to introduce in the macromolecule peculiar features for specific industrial applications.
Synthesis of antioxidant polymers by grafting of gallic acid and catechin on gelatin
Spizzirri, Ug;Iemma, F;Puoci, F;Cirillo, G;Curcio, M;Parisi, Oi;Picci, Nevio
2009-01-01
Abstract
A novel, simple, and cheap method to synthesize antioxidant-protein conjugates by grafting reaction was developedemploying a hydrogen peroxide-ascorbic acid pair as radical initiator system. Our challenge was to covalentlybind molecules with tested antioxidant activity, as gallic acid (GA) and catechin (CT) to a biomacromolecule, asgelatin, extensively used in the pharmaceutical, cosmetic, and food industry. In this way, two gelatin conjugates,bearing GA and CT covalently bounded to a side chain of protein, were synthesized. Calorimetric, UV-vis, andfluorescence analyses were performed to verify the covalent bond between antioxidant molecules and gelatin,and the antioxidant activity of conjugates was compared to that of a control polymer submitted to the samereaction conditions without antioxidant molecule. The ability of synthesized materials to inhibit 2,2′-diphenyl-1-picrylhydrazyl, hydroxyl radicals, and linoneic acid peroxidation was determined and, to well characterizedantioxidant properties of grafted biomacromolecules, disposable phenolic equivalents and total antioxidant activitywere calculated. The conjugates showed a good antioxidant activity, confirming the efficiency of the syntheticstrategy proposed in this paper. The results clearly showed that antioxidant moieties covalently bounded to anatural polymer allow to introduce in the macromolecule peculiar features for specific industrial applications.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
