Improvement of antioxidant activity of chitosan by chemical treatment and ionizing radiation.
Modification of chitosan (CS) to N-maleoylchitosan (NMCS), N-phthaloylchitosan (NPhCS) and sulfonated-chitosan (SCS) was done using maleic anhydride, phthalic anhydride and chlorosulfonic acid, respectively followed by exposing them to γ-rays at different doses. The molecular weights and structural changes of irradiated chitosan derivatives were determined by GPC, FT-IR and UV-vis spectrophotometer. The molecular weights decreased with increasing irradiation dose. Results revealed that the main polysaccharide structure remained after irradiation. To investigate the enhancement of antioxidant activity of chitosan and its derivatives of different molecular weights, radical mediated lipid peroxidation inhibition, scavenging effect of DPPH radicals, reducing power and ferrous ion chelating activity assays were used. Chitosan derivatives with different molecular weights exhibit antioxidant activity. The lower the molecular weights of chitosan and its derivatives, the higher the antioxidant activity. NMCS possessed high scavenging effect on DPPH radicals compared with NPhCS, SCS and ascorbic acid. The irradiated chitosan and its derivatives could be used as natural antioxidants.
Department of Radiation Research of Polymer Chemistry, National Center for Radiation Research and Technology (NCRRT), Cairo, Egypt. ha_rehim@hotmail.com
Hassan A
HA
Abd El-Rehim
Naeem M
NM
El-Sawy
El-Sayed A
el-SA
Hegazy
El-Sayed A
el-SA
Soliman
Ahmed M
AM
Elbarbary
D002236:Carbohydrate Conformation / Q000528:radiation effects; D048271:Chitosan / Q000138:chemical synthesis / Q000737:chemistry* / Q000494:pharmacology*; D016166:Free Radical Scavengers / Q000138:chemical synthesis / Q000737:chemistry* / Q000494:pharmacology*; D005609:Free Radicals / Q000037:antagonists & inhibitors; D007502:Iron Chelating Agents / Q000737:chemistry / Q000494:pharmacology; D008970:Molecular Weight; D010084:Oxidation-Reduction / Q000528:radiation effects; D011839:Radiation, Ionizing
D016166:Free Radical Scavengers; D005609:Free Radicals; D007502:Iron Chelating Agents; D048271:Chitosan