Structural characterization of a novel glucan from Achatina fulica and its antioxidant activity.

A novel glucan designated AFPS-IB was purified from Achatina fulica (China white jade snail) by anion-exchange and gel-permeation chromatography. Chemical composition analysis indicated AFPS-IB was composed of glucose, fucose, rhamnose, mannose, and galactose in a molar ratio of 189:2:1:1:2 and with an average molecular weight of 128 kDa. Its structural characteristics were investigated by Fourier transform infrared spectroscopy (FTIR), high performance liquid chromatography (HPLC), gas chromatography mass spectrometry (GC-MS), methylation analysis, nuclear magnetic resonance (NMR) spectroscopy ((1)H,( 13)C, H-H COSY, HSQC, TOCSY, and NOESY), and atomic force microscopy (AFM). The glucan mainly consisted of a backbone of repeating (1→4)-α-d-glucose residues with (1→6)-ß-d glucosyl branches at random points on the backbone glucose. Antioxidant studies revealed AFPS-IB showed significant DPPH (2,2-diphenyl-1-picrylhydrazyl) radical, superoxide anion (O2(-)) scavenging activities and high reduction potential. This study suggested that AFPS-IB could be a new source of dietary antioxidants.

Depolymerization of fucosylated chondroitin sulfate from sea cucumber, Pearsonothuria graeffei, via 60Co irradiation.

A method for depolymerization of a novel fucosylated chondroitin sulfate from Pearsonothuria graeffei (fCS-Pg) using (60)Co irradiation in water solution was developed in the current study. Fragments with varying molecular weights were obtained by (60)Co irradiation at different dosages and sample concentrations. The chemical compositions and structures of these fragments were further investigated using high-performance liquid chromatography (HPLC), infrared spectroscopy (IR) and nuclear magnetic resonance spectroscopy (NMR). Our results indicated that (60)Co irradiation induced depolymerization via selective breakage of glucuronic acid units in the fCS-Pg backbone, with no obvious influence on sulfated fucose branches under mild conditions. The recommended conditions for fCS-Pg degradation were 2-10% solution concentration and irradiation dosages of 10-50kGy. The anticoagulant activities of the low molecular weight fragments were additionally evaluated. Notably, anticoagulant activities were reduced with decreasing molecular weights. Compared to the native fCS-Pg, low molecular weight fragments displayed significantly decreased anticoagulant activities. Based on the collective findings, we propose that these fragments are potentially applicable as antithrombotic agents with reduced bleeding risk relative to native fCS-Pg.