Degradation of porphyran from Porphyra haitanensis and the antioxidant activities of the degraded porphyrans with different molecular weight

• Published in: International journal of biological macromolecules Vol. 38; no. 1; pp. 45 - 50
• Main Authors: Zhao, Tingting, Zhang, Quanbin, Qi, Huimin, Zhang, Hong, Niu, Xizhen, Xu, Zuhong, Li, Zhien
• Format: Journal Article
• Language: English
• Published: Netherlands Elsevier B.V 28.02.2006
• Subjects: Antioxidant activities; Antioxidants - chemistry; Antioxidants - metabolism; Antioxidants - pharmacology; Ascorbate; Ascorbic Acid; Biodegradation, Environmental; Degradation; Free Radicals; Hydrogen Peroxide; Hydrogen peroxide (H 2O 2); Molecular Weight; Porphyra - metabolism; Porphyra haitanensis; Porphyran; Sepharose - analogs & derivatives; Sepharose - chemistry; Sepharose - metabolism; Sepharose - pharmacology; Degradation; Ascorbate; Antioxidant activities; Porphyra haitanensis; Hydrogen peroxide (H 2O 2); Porphyran
• ISSN: 0141-8130; 1879-0003
• DOI: 10.1016/j.ijbiomac.2005.12.018

In the present paper, ascorbate and hydrogen peroxide (H 2O 2) were used to degrade porphyran. It was found that porphyran could be degraded by free radical that was generated by ascorbate and H 2O 2 in combination. It was possible to prepare desired porphyran products with different molecular weight by adjusting ascorbate to H 2O 2 proportions and their concentrations. The molar ratio of 1 was demonstrated more effective than in other ratios. Higher concentrations accelerated the degradation. Moreover, results of chemical analysis and FT-IR spectra suggested that the main structure of degraded products still remained although some changes happened. The degraded and natural porphyrans possessed scavenging 1,1-diphenyl-2-picrylhydrazyl (DPPH)-radical activity and reducing power. Higher antioxidant activities were found in both systems when the molecular weight was reduced. The results indicated that the antioxidant activities were closely related to the molecular weight. The degraded porphyrans are potential antioxidant in vitro.