Synthesis and Evaluation of Chitosan-Vitamin C complex

Abstract

Chitosan is a biocompatible, biodegradable and non-toxic polysaccharide polymer. It dissolves in water only if the pH is lower than 6.5. To extend its range of application, many water-soluble derivatives have therefore been prepared. In this research, chitosan-vitamin C complex was synthesized and characterized with Fourier transformed infrared spectroscopy, differential scanning calorimetry and (1)H-NMR. The solubility of chitosan-vitamin C complex in distilled water was greatly improved. The *O(2) (-) scavenging activity of chitosan-vitamin C complex was compared with chitosan and vitamin C by measuring the auto-oxidation rate of pyrogallic acid. Results showed that the scavenging activity on *O(2) (-) by chitosan-vitamin C complex was stronger than that by CS. At low concentrations (< 0.05 mg/ml), the scavenging activity of chitosan-vitamin C complex was stronger than that of vitamin C, but after certain concentrations (>0.1mg/ml), its scavenging activity was lower than that of vitamin C.

Keywords: Polymer; antioxidation; chitosan; intrinsic viscosity; vitamin C.

Fig. 1

Possible reaction mechanism between CS and vitamin C

Fig. 2

FT-IR spectra of CS, vitamin C, CS-vitamin C mixture and complexes. FT-IR spectra of a. chitosan (CS), b. vitamin C, c. CS-vitamin C mixture and d. CS-vitamin C complexes.

Fig. 3

DSC thermographs of CS, vitamin C, CS-vitamin C mixture and complexes. The differential scanning calorimeteric thermographs of a. chitosan (CS), b. vitamin C, c. CS-vitamin C mixture and d. CS-vitamin C complexes

Fig. 4

¹H-NMR spectra of CS, vitamin C and CS-vitamin C complexes ¹H-NMR spectra of chitosan (CS, a), vitamin C (b) and CS-vitamin C complexes (c)

Fig. 5

Crystalline structure of CS

Fig. 6

Antioxidation rates of CS, CSVC and VC. Antioxidation rates of chitosan (CS, –▲–), chitosan vitamin C complex (CSVC, –▪–) and Vitamin C (VC,…◆…)