Molecular Characterization and Bioactivities of a Novel Polysaccharide from Phyllostachys pracecox Bamboo Shoot Residues

Dietary carbohydrates are unexploited in the by-products of economically valuable Phyllostachys pracecox bamboo shoots. A residue-derived polysaccharide (PBSR1) was aqueously extracted from the processing waste of this bamboo shoot species. Its primary structure and advanced conformation were elucidated by a combined analysis of spectroscopy, chromatography, 2D nuclear magnetic resonance, laser light scattering and atomic microscopy. The results indicated PBSR1 was a triple-helix galactan consisting of -> 6)-beta-D-Galp and -> 3)-beta-D-Galp in linear with an 863 KD molecular weight (M-w). The relationship between the radius of gyration (R-g) and intrinsic viscosity ([eta]) on M-w were established as R-g = 1.95 x 10(-2)M(w) (0.52 +/- 0.03) (nm) and [eta] = 9.04 x 10(-1)M(w)(0.56 +/- 0.02) (mL/g) for PBSR1 in saline solution at 25 degrees C, which indicated it adopted a triple-helix chain shape with a height of 1.60 +/- 0.12 nm supported by a red shift of lambda(max) in Congo red analysis. The thermodynamic test (TG) displayed that it had excellent thermal stability for the food industry. Further, those unique structure features furnish PBSR1 on antioxidation with EC50 of 0.65 mg/mL on DPPH center dot and an ORAC value of 329.46 +/- 12.1 mu mol TE/g. It also possessed pronounced immunostimulation by up-regulating pro-inflammatory signals including NO, IL-6, TNF-alpha and IL-1 beta in murine cells. Our studies provided substantial data for the high-valued application of residues and a better understanding of the structure-function relationship of polysaccharide.

Automated summary

A polysaccharide (PBSR1) extracted from the processing waste of Phyllostachys pracecox bamboo shoots was found to be a triple-helix galactan with excellent thermal stability and antioxidant properties, as well as immunostimulatory effects.