Purification of polysaccharide isolated from “Matthiola longipetala”: structure characterization and antioxidant activities

Abstract

Abstract Purpose: In this study, the polysaccharides isolated from Matthiola logipetala (PSMT) purified by DEAE-Sepharose chromatography. Tow fractions of polysaccharides, PSMT1 and PSMT2 were obtained. Methods: The PSMT1 and PSMT2 structures and physicochemical proprieties were investigated using chemical and instrumental analysis, including Fourier transform infrared (FT-IR) spectroscopy, spectrum visible UV, nuclear magnetic spectroscopy (1H-NMR and 13C-NMR), X-ray diffraction (XRD) and Scanning Electron Microscopy (SEM). Results: The results of high-performance liquid chromatography (HPLC-MS) showed that the both purified polysaccharides PSMT1 and PSMT2 were mainly composed of rhamnose, arabinose, glucose and galactose in a molar percent in 39.69%, 29.59%, 8.81% and 21.89%, respectively for PSMT1 and 38.5%, 28.71%,15.1% and 17.676% respectively for PSMT2.The data of thermogravimetry analysis (TGA) and differential scanning calorimetry (DSC) indicated that PSMT1 and PSMT2 had relatively high thermal stability. The result of gel permeation chromatography (GPC) showed that PSMT1 and PSMT2 had a relative molecular weight of 9.779 kDa and 115.004 kDa respectively. Moreover, the in vitro antioxidant activities of PSMT were evaluated by DPPH free radical assay, ferrous iron–chelating, assay and total antioxidant activity. The experimental results showed that PSMT1 and PSMT2 exhibited an appreciable in vitro antioxidant potential. Conclusion: Our results revealed that PSMT1 and PSMT2, polysaccharides purified from Matthiola longipetala could be novel active biomolecules with antioxidant proprieties, which promoting their application in the food and pharmaceutical fields.