title: New agar microspheres for the separation and purification of natural products.
abstract: A new type of agar chromatography media has been prepared with a yield over 80% using a water-in-oil emulsion technique. These microspheres have regular spherical shapes and particle diameters in the range 40-165 μm (average ∼90 μm). Cross-linking of the resulting agar microspheres with epichlorohydrin and 1,4-butanediol diglycidyl ether enhanced their mechanical and thermal stability. The alkaline conditions used during the cross-linking reaction also decreased the content of ionized sulfate groups of the polysaccharide, thus reducing the nonspecific adsorption of positively charged molecules. The cross-linked agar microspheres were functionalized with (i) branched poly(ethyleneimine) to obtain a stationary phase useful for the separation of proteins in an anion-exchange mode and (ii) with poly-β-cyclodextrin enabling direct isolation and purification of puerarin from a crude extract of Radix puerariae. Using a 23.5 mL column loaded with 20 mg extract (0.85 mg/mL gel), puerarin with a purity of 96% was recovered with a yield of 86%.
authors.affiliation: Beijing Key Lab of Bioprocess, College of Life Science and Technology, Beijing University of Chemical Technology, Beijing, China.
authors.forename: Chunling
authors.initials: C
authors.lastname: Ge
authors.forename: Yu
authors.initials: Y
authors.lastname: Hu
authors.forename: Fan
authors.initials: F
authors.lastname: Zhang
authors.forename: Yongqin
authors.initials: Y
authors.lastname: Lv
authors.forename: Tianwei
authors.initials: T
authors.lastname: Tan
mesh_terms: D000362:Agar / Q000737:chemistry*; D001688:Biological Products / Q000032:analysis*; D002072:Butylene Glycols / Q000032:analysis*; D002626:Chemistry, Pharmaceutical; D002852:Chromatography, Ion Exchange; D003432:Cross-Linking Reagents / Q000737:chemistry; D003505:Cyclodextrins / Q000032:analysis*; D004365:Drugs, Chinese Herbal / Q000378:metabolism; D004811:Epichlorohydrin / Q000032:analysis*; D008516:Medicine, Chinese Traditional; D008863:Microspheres; D010936:Plant Extracts / Q000032:analysis; D011094:Polyethyleneimine / Q000737:chemistry; D011108:Polymers / Q000737:chemistry; D029908:Pueraria; D015203:Reproducibility of Results; D012685:Sepharose / Q000737:chemistry
chemical_list: D001688:Biological Products; D002072:Butylene Glycols; D003432:Cross-Linking Reagents; D003505:Cyclodextrins; D004365:Drugs, Chinese Herbal; D010936:Plant Extracts; D011108:Polymers; C442842:plant extract, Puerariae Radix; D004811:Epichlorohydrin; D000362:Agar; D011094:Polyethyleneimine; D012685:Sepharose
keywords: Agar; Cyclodextrin; Flavanoids; Microspheres; Proteins