Relative molecular mass distribution and monosaccharide composition of polysaccharides in Polygonatum kingianum var.grandifolium

Abstract

Polygonatum kingianum var.grandifolium, different from most Polygonatum species in biological characteristics, sprouts and blooms in spring and autumn, respectively, and it is evergreen in winter.It is difficult to learn from the patterns of other Polygonatum plants because the chemical composition in P.kingianum var.grandifolium changes with phenology, which consequently restricts the production of high-quality medicinal and eatable substances.Samples of P.kingianum var.grandifolium in different months and ages collected from Xiushan, Chongqing were analyzed for polysaccharide content, polysaccharide relative molecular mass, and mono-saccharide composition by anthrone-sulfuric acid colorimetric assay, high-performance gel-permeation chromatography, and trimethylsilane(TMS) derivatization prior to GC-MS.The results showed that the polysaccharide content and composition in the rhizome of P.kingianum var.grandifolium were closely related to the growth period.New shoot sprouting promoted the accumulation of polysaccharides, and flowering and fruiting consumed polysaccharides.The highest polysaccharide content was found in April, reaching 134.04 mg·g~(-1).Polysaccharides in P.kingianum var.grandifolium were divided into five fractions according to the weight-average M_W, i.e., P1(2.02×10~7), P2(5.09×10~6), P3(1.37×10~6), P4(4.73×10~5), and P5(5.11×10~3), and P5 had the highest content.In terms of monosaccharide composition, polysaccharides were mainly composed of fructose, glucose, galactose, mannose, xylose, and arabinose with the average molar ratio of 1.31∶1.00∶0.90∶0.53∶0.22∶0.21.The results of the study provide a scientific basis for the precise harvesting and resource utilization of P.kingianum var.grandifolium.