Preparation and Characterization of Nano-Selenium Decorated by Chondroitin Sulfate Derived from Shark Cartilage and Investigation on Its Antioxidant Activity

Abstract

In the present study, a selenium-chondroitin sulfate (SeCS) was synthesized by the sodium selenite (Na₂SeO₃) and ascorbic acid (Vc) redox reaction using chondroitin sulfate derived from shark cartilage as a template, and characterized by SEM, SEM-EDS, FTIR and XRD. Meanwhile, its stability was investigated at different conditions of pH and temperatures. Besides, its antioxidant activity was further determined by the DPPH and ABTS assays. The results showed the SeCS with the smallest particle size of 131.3 ± 4.4 nm and selenium content of 33.18% was obtained under the optimal condition (CS concentration of 0.1 mg/mL, mass ratio of Na₂SeO₃ to Vc of 1:8, the reaction time of 3 h, and the reaction temperature of 25 °C). SEM image showed the SeCS was an individual and spherical nanostructure and its structure was evidenced by FTIR and XRD. Meanwhile, SeCS remained stable at an alkaline pH and possessed good storage stability at 4 °C for 28 days. The results on scavenging free radical levels showed that SeCS exhibited significantly higher antioxidant activity than SeNPs and CS, indicating that SeCS had a potential antioxidant effect.

Keywords: antioxidant activity; chondroitin sulfate derived from shark cartilage; nanoselenium; structure characterization.

Figure 1

Effects of different template dosage (A), reactants ratio (B), reaction time (C), and reaction temperatures (D) on particle size of SeCS. Bars with a1, b1 and c1 represented a statistical difference (p < 0.05) among different template dosages. Bars with a2 and b2 represented a statistical difference (p < 0.05) among different reactants ratios. Bars with a3, b3 and c3 represented a statistical difference (p < 0.05) among different times. Bars with a4 and b4 represented a statistical difference (p < 0.05) among different reaction temperatures.

Figure 2

SEM images of SeNPs (A,C) and SeCS (B,D) powders. The SeNPs were obtained in the same procedure of SeCS without CS.

Figure 3

SEM-EDS element analysis of CS (A), SeNPs (B) and SeCS (C). The SeNPs were obtained in the same procedure of SeCS without CS.

Figure 4

FT-IR spectra of CS, SeNPs and SeCS. The SeNPs were obtained in the same procedure of SeCS without CS.

Figure 5

XRD patterns of CS, SeNPs and SeCS. The SeNPs were obtained in the same procedure of SeCS without CS.

Figure 6

Effects of different pHs (A) and storage temperatures (B) on the size of SeCS. The initial pH value of the control group was 6.8. p < 0.05 (*) or p < 0.01 (**) means that columns between control group and other groups are significantly different.

Figure 7

DPPH radical scavenging rate (A) and ABTS radical scavenging rate (B) of SeCS. p < 0.05 (*) or p < 0.01 (**) means that columns between SeCS at 0.1 mg/mL and SeCS at other concentrations are significantly different. p < 0.01 (##) means that columns between SeNPs at 0.1 mg/mL and SeNPs at 0.4 mg/mL are significantly different. p < 0.05 (&) or p < 0.01 (&&) means that columns between SeCS at 20 μg/mL and SeCS at other concentrations are significantly different. p < 0.05 (@) means that columns between SeNPs at 20 μg/mL and SeNPs at other concentrations are significantly different.