Interaction Between Bovine Serum Albumin And Some Active Components Of Traditional Chinese Herb

The intermolecular action between small molecules and biomacromolecules is one of theessential matters in life science. However, less attention has been paid to the interactionbetween the active component of traditional Chinese Herb and biomacromolecules. In thispaper, the interaction between bovine serum albumin (BSA) and the active component ofsome traditional Chinese Herb was studied.In the Introduction section, more than 150 literatures were cited, the status quo of medicinemolecules and biomacromolecules interaction was summarized briefly. In Chap. 1, threekinds of Chinese herbal active component, such as BC, Câ…¢ were prepared by extracting andseparating from natural Chinese Herbs, and the others such as Câ… , Câ…¡, Câ…£, and Câ…¤weresynthesized. The Chap. 2 is the central parts of this paper, intermolecular action signals of theabove medicine-BSA systems were obtained by means of ultraviolet-visible spectroscopy(UV-Vis), fluorescence spectroscopy (FS), synchronous fluorescence spectroscopy, circulardichroism (CD), cyclic voltammetry (CV) etc. Idiographic information of Chinese herbalactive component-BSA interaction were obtained from above signals, thereout, the relativelyconsummate information system of Chinese herbal active component-BSA interaction wasconstructed. From Chap. 3 to Chap. 5 are expanding parts of this paper. In Chap. 3, a seriesof coumarin generic Chinese herbal active components were chosen as the typical toinvestigate the structure-performance relationship (SPR) in medicine-BSA interaction process.In Chap. 4, the bioinorganic effects of four metal ions (Me²⁺), such as Cu²⁺, Ni²⁺, Zn²⁺, andCo²⁺ on Chinese herbal active component-BSA interaction process were discussed. In Chap. 5,integrating the results of Chap. 4, the participant manner and the interferential mechanism ofthe other categories of adscititious reagents were discussed also. The contents of simple studyof cooperativity, rationality validation of presupposition in the quantitative equationestablishing (in Chap. 2) and the resonance Rayleigh scattering (RRS) spectral character ofmedicine-BSA interaction were arranged in Chap. 6.In the experimental range of this paper, the main conclusions are summarized as following.1. The relatively consummate information system of Chinese herbal active component-BSAinteraction was constructed. All information are composed of the quenching type, thestatic quenching constant (KP), the apparent association constant (KA), the number ofmedicine binding sites (n), the spatial distance (r) between medicine molecules and thefluorescence residues of BSA, and the efficiency of intermolecular energy transfer (E),transition of BSA molecular conformation, the thermodynamic parameters, the main typeof driving force, and the cooperativity of intermolecular binding, etc. The aboveinformation system is capable of affording essential information in Chinese herbal activecomponent-BSA interaction process. The SPR, the participant manner and theinterferential mechanism of adscititious reagents, and the bioinorganic effect of Me2+ canbe successfully explained by the information systems.2. The interaction between medicine and BSA is influenced by the structural variety ofmedicine molecule. To coumarin generic Chinese herbal active components, suchsubstituted groups as 4-CH3, 6-OH, 7-OH and 7-OCH3 in coumarin-ring are the probableacting groups in medicine-BSA interaction, bearing the simultaneous functions ofpromoting and obstructing. The process of medicine-BSA binding is promoted stronglyby both 4-CH3 and 6-OH substituted in coumarin molecules, but the latter has to enduresimultaneously some adverse effects caused by increment of molecular polarity andstereo hindrance. Decreasing the polarity and increasing the volume of 7-substituentdestroys the medicine-BSA binding, and the effect is almost totally opposite to that of6-OH. All of these results may afford evidence for medicine screening and understandingthe laws of medicine-protein interaction.3. Analogous to the Irving-Williams stability series, when the four metal ions Cu2+, Ni2+,Zn2+or Co2+ participated respectively in same medicine-BSA system, the orderliness ofthe complex stability changing and the efficacy of BSA intrinsic fluorescence beingquenched were summed up, reflecting the bioinorganic effects of the Me2+ on theinteraction between medicine and BSA.4. The participant manner and the interferential mechanism of the adscititious reagents aredifferent each other. BSA molecular conformational transition due to Me2+ and otherkinds of adscititious reagents bound to BSA is the common mechanism of theadscititious reagent participating in medicine-BSA interaction process. Except for this,the others such as ionic bridge (e.g. Me2+, I-), appositional replacement (e.g. SB) anddestroying the binding site(s) (e.g. SDS) etc. is involved in also.5. The type of BSA intrinsic fluorescence being quenched is mainly static quenching, andthe nonradiative energy transfer is attributed to BSA intrinsic fluorescence beingquenched also. The process of Chinese Herbal active component-BSA interaction is aspontaneous molecular process in which entropy increases and Gibbs free energydecreases. The entropy increasing is the common energetic driving factor formedicine-BSA interaction. Except for this, the hydrophobic forces or dipole-dipoleforces are the main type of driving force in Chinese Herbal active component-BSAinteraction. The characteristic signals in RRS spectrum of BSA were analyzed simply.The changing behavior of RRS spectrum for Câ…¢-BSA binary systems or Câ…¢-BSA-adscititious reagent ternary systems is the potential evidence for complex forming,intermolecular nonradiative energy transfer, BSA intrinsic fluorescence being quenched,transition of BSA molecular conformation, and the interferential mechanism ofadscititious reagents, etc.