title: Microwave-Assisted Extraction, Chemical Structures, and Chain Conformation of Polysaccharides from a Novel Cordyceps Sinensis Fungus UM01.
abstract: Cordyceps sinensis is a well-known tonic food with broad medicinal properties. The aim of the present study was to investigate the optimization of microwave-assisted extraction (MAE) and characterize chemical structures and chain conformation of polysaccharides from a novel C. sinensis fungus UM01. Ion-exchange and gel filtration chromatography were used to purify the polysaccharides. The chemical structure of purified polysaccharide was determined through gas chromatography-mass spectrometry. Moreover, high performance size exclusion chromatography combined with refractive index detector and multiangle laser light scattering were conducted to analyze the molecular weight (Mw ) and chain conformation of purified polysaccharide. Based on the orthogonal design L9 , optimal MAE conditions could be obtained through 1300 W of microwave power, with a 5-min irradiation time at a solid to water ratio of 1:60, generating the highest extraction yield of 6.20%. Subsequently, the polysaccharide UM01-S1 was purified. The UM01-S1 is a glucan-type polysaccharide with a (1→4)-β-d-glucosyl backbone and branching points located at O-3 of Glcp with a terminal-d-Glcp. The Mw , radius of gyration (Rg ) and hydrodynamic radius (Rh ) of UM01-S1 were determined as 5.442 × 10(6)  Da, 21.8 and 20.2 nm, respectively. Using the polymer solution theory, the exponent (ν) value of the power law function was calculated as 0.38, and the shape factor (ρ = Rg /Rh ) was 1.079, indicating that UM01-S1 has a sphere-like conformation with a branched structure in an aqueous solution. These results provide fundamental information for the future application of polysaccharides from cultured C. sinensis in health and functional food area.
authors: State Key Laboratory of Quality Research in Chinese Medicine, Inst. of Chinese Medical Sciences, Univ. of Macau, Macao, China.
authors: Kit-Leong
authors: KL
authors: Cheong
authors: State Key Laboratory of Quality Research in Chinese Medicine, Inst. of Chinese Medical Sciences, Univ. of Macau, Macao, China.
authors: Lan-Ying
authors: LY
authors: Wang
authors: State Key Laboratory of Quality Research in Chinese Medicine, Inst. of Chinese Medical Sciences, Univ. of Macau, Macao, China.
authors: Ding-Tao
authors: DT
authors: Wu
authors: State Key Laboratory of Quality Research in Chinese Medicine, Inst. of Chinese Medical Sciences, Univ. of Macau, Macao, China.
authors: De-Jun
authors: DJ
authors: Hu
authors: State Key Laboratory of Quality Research in Chinese Medicine, Inst. of Chinese Medical Sciences, Univ. of Macau, Macao, China. zhaojing.cpu@163.com.
authors: Jing
authors: J
authors: Zhao
authors: State Key Laboratory of Quality Research in Chinese Medicine, Inst. of Chinese Medical Sciences, Univ. of Macau, Macao, China.
authors: Shao-Ping
authors: SP
authors: Li
mesh_terms: D002850:Chromatography, Gel; D032661:Cordyceps / Q000737:chemistry*; D005511:Food Handling; D005516:Food Microbiology; D008401:Gas Chromatography-Mass Spectrometry; D005936:Glucans / Q000737:chemistry / Q000302:isolation & purification; D007474:Ion Exchange; D008872:Microwaves; D015394:Molecular Structure; D008970:Molecular Weight; D011134:Polysaccharides / Q000737:chemistry* / Q000302:isolation & purification*; D014867:Water / Q000737:chemistry
chemical_list: D005936:Glucans; D011134:Polysaccharides; D014867:Water
keywords: Cordyceps sinensis; chain conformation; microwave-assisted extraction; polysaccharide