Structure characterization, modification through carboxymethylation and sulfation, and in vitro antioxidant and hypoglycemic activities of a polysaccharide from Lachnum sp

• Published in: Process biochemistry (1991) 2018-09, Vol.72, p.177-187
• Main Authors: Wang, Yufen, Hou, Guohua, Li, Jinglei, Surhio, Maheen Mahwish, Ye, Ming
• Format: Article
• Language: English
• Subjects: Antioxidant activity; Antioxidants; Carboxymethylation; Diffusion effects; Exopolysaccharides; Fermented food; Fourier transforms; Gas chromatography; Glucose; Glucose diffusion; Glucosidase; High performance liquid chromatography; Hydroxyl radicals; Hypoglycemia; Hypoglycemic activity; Infrared analysis; Lachnum polysaccharide; Liquid chromatography; Magnetic resonance spectroscopy; Mass spectrometry; Mass spectroscopy; Molecular weight; NMR; Nuclear magnetic resonance; Polysaccharides; Scavenging; Structural analysis; Structure; Sufation; Sulfation; α-Amylase; α-Glucosidase
• ISSN: 1359-5113; 1873-3298
• DOI: 10.1016/j.procbio.2018.06.002

Legend: CLEP is the carboxymethylated of LEP. SLEP is the sulfated derivatives of LEP. [Display omitted] •Carboxymethylated and sulfated derivatives of LEP were prepared.•The antioxidation by three activities and hypoglycemic by three activities in vitro of LEP and its derivatives were compared.•CLEP is superior to SLEP.•The bioactivities are affected by the types of substitution groups and their degree of substitution. An exopolysaccharide (LEP) was isolated from the fermented broth of Lachnum YM240. The structure of LEP was analyzed by fourier transform infrared spectrometry (FT-IR), high performance liquid chromatography (HPLC), gas chromatography-mass spectrometry (GCMS), and 1D and 2D-nuclear magnetic resonance spectroscopy (NMR). The carboxymethylated and sulfated derivatives of LEP was difined as CLEP and SLEP which with molecular weight (Mw) of 3.64 × 104 and 2.17 × 104 g/mol respectively. The yield of CLEP and SLEP were 60.27 ± 3.04% and 42.88 ± 2.16%, with degree of substitution (DS) values of 0.36 and 0.14 respectively. The result of antioxidant activity and hypoglycemic activity showed that CLEP with higher (DS) and (Mw) exhibited stronger antioxidant abilities on scavenging DPPH radical and hydroxyl radical compared with SLEP and LEP, with EC50 value of 1.05 and 0.80 mg/mL respectively. The reducing power of CLEP (0.533) and SLEP (0.428) was greater than LEP (0.353). In addition, CLEP and SLEP showed higher alpha-glucosidase inhibitory and alpha-amylase inhibition activities and exhibited significant inhibitory effects against the diffusion of glucose compared to LEP. Furthermore, CLEP and SLEP showed more significant effects than LEP at the same dosage, indicating that carboxymethylation and sulfation modifications were effective ways to enhance antioxidant and hypoglycemic activities of the polysaccharide.