Synthesis of chitosan-gallic acid conjugate: structure characterization and in vitro anti-diabetic potential.
In this study, chitosan grafted copolymer with gallic acid (GA) was synthesized by a novel and efficient free radical mediated method. The optimal grafting conditions, structural characterization, α-glucosidase and α-amylase inhibitory activities of chitosan grafted copolymers were investigated. Results showed that the maximum grafting ratio (128.3 mg GA equivalents/g) was obtained at 12 h with 5 g/L chitosan, 16 g/L GA, 2 g/L ascorbic acid and 0.2 M hydrogen peroxide. UV-vis, Fourier-transform infrared and nuclear magnetic resonance spectroscopy all confirmed the successful grafting of GA onto chitosan. The conjugation of GA onto chitosan probably occurred between amine (C-2), hydroxyl groups (C-3 and C-6) of chitosan and carboxyl groups of GA, forming amide and ester linkages, respectively. Differential scanning calorimetry and X-ray diffraction spectra indicated that GA grafted chitosan (GA-g-chitosan) had decreased thermal stability and crystallinity as compared to chitosan. Notably, GA-g-chitosan showed increased α-glucosidase and α-amylase inhibitory activity with the increase of grafting ratio. These results indicated the potential of GA-g-chitosan in the development of an effective anti-diabetic agent.
College of Food Science and Engineering, Yangzhou University, Yangzhou 225127, Jiangsu, China. Electronic address: junliu@yzu.edu.cn.
Jun
J
Liu
Jian-feng
JF
Lu
Juan
J
Kan
Chang-hai
CH
Jin
D001205:Ascorbic Acid / Q000737:chemistry; D001272:Atmosphere; D060326:Chemistry Techniques, Synthetic / Q000379:methods*; D048271:Chitosan / Q000737:chemistry*; D005609:Free Radicals / Q000737:chemistry; D005707:Gallic Acid / Q000737:chemistry*; D065089:Glycoside Hydrolase Inhibitors / Q000138:chemical synthesis / Q000737:chemistry / Q000494:pharmacology; D006861:Hydrogen Peroxide / Q000737:chemistry; D007004:Hypoglycemic Agents / Q000138:chemical synthesis* / Q000737:chemistry* / Q000494:pharmacology; D013696:Temperature; D000516:alpha-Amylases / Q000037:antagonists & inhibitors; D000520:alpha-Glucosidases / Q000378:metabolism
D005609:Free Radicals; D065089:Glycoside Hydrolase Inhibitors; D007004:Hypoglycemic Agents; D005707:Gallic Acid; D048271:Chitosan; D006861:Hydrogen Peroxide; D000516:alpha-Amylases; D000520:alpha-Glucosidases; D001205:Ascorbic Acid
Chitosan; Diabetes mellitus; Gallic acid; Graft copolymer; Redox pair