title: Based on SERS conformational studies of ginsenoside Rb1 and its metabolites before and after combined with human serum albumin.
abstract: Surface-enhanced Raman scattering (SERS) and fluorescence spectroscopy were employed to probe the interaction of the pharmaceutical and natural product molecules, ginsenoside Rb1, Rd, Rg3 and compound K (CK), with human serum albumin (HSA). Normal Raman spectra of these four ginsenosides were obtained from solid powder on glass slide. Based on the unsplit peak at 1445 cm(-1), the stacking modes of ginsenoside Rb1, Rd, Rg3 and CK were quite similar, when the deconvolution of alkyl chain was not occurred. SERS spectra of ginsenoside Rb1, Rd, Rg3 and CK were obtained from a colloidal silver surface on a self-assembled SERS substrate, the most enhanced modes were those with certain motions perpendicular to the metal surface, such as C24C25 stretch and CH out-of-plane bending from alkyl chain. The SERS spectra were used to predict similar perpendicular orientation of flexible alkyl chain and parallel orientation of carbocyclic rings on Ag colloid particles. Therefore, when combined with HSA, the transformations of four ginsenosides still exhibit similar, although in different binding cavities in subdomain IIA and IIIA by making the methyls at C26 and C27 perpendicular plugging into the hydrophobic site of HSA, while the aglycone and glucose nearby are perpendicularly exposed outside to fit other suitable active targeting sites.
authors.affiliation: Institute of Special Animal and Plant Sciences, Chinese Academy of Agricultural Sciences, Changchun 130112, PR China.
authors.forename: Wei
authors.initials: W
authors.lastname: Zhang
authors.affiliation: Institute of Special Animal and Plant Sciences, Chinese Academy of Agricultural Sciences, Changchun 130112, PR China. Electronic address: yingpingwcaas@126.com.
authors.forename: Yingping
authors.initials: Y
authors.lastname: Wang
authors.affiliation: Changchun University of Chinese Medicine, Changchun 130117, PR China. Electronic address: baixy1212@163.com.
authors.forename: Xueyuan
authors.initials: X
authors.lastname: Bai
authors.affiliation: State Key Laboratory of Supramolecular Structure and Materials, Jilin University, Changchun 130012, PR China.
authors.forename: Bing
authors.initials: B
authors.lastname: Zhao
mesh_terms: D036145:Ginsenosides / Q000737:chemistry* / Q000378:metabolism*; D006801:Humans; D053768:Metal Nanoparticles / Q000737:chemistry / Q000648:ultrastructure; D008958:Models, Molecular; D012709:Serum Albumin / Q000378:metabolism*; D012834:Silver / Q000737:chemistry; D013050:Spectrometry, Fluorescence; D013059:Spectrum Analysis, Raman / Q000379:methods
chemical_list: D036145:Ginsenosides; D012709:Serum Albumin; D012834:Silver; C442759:ginsenoside Rb1
keywords: Ginsenoside Rb1/Rd/Rg3/CK; Human serum albumin; Surface-enhanced Raman scattering