A new monacolin analogue from Xuezhikang capsule.

Xuezhikang capsule (ethanol extract of red yeast rice) which produced by Beijing WBL Peking University Biotech Co., Ltd., is a traditional Chinese medication with 3-hydroxy-3-methylglutaryl-coenzyme A (HMG-CoA) reductase inhibiting activity. Clinical trials indicated that Xuezhikang with lipid-lowering action could reduce the risk of cardiac events and total mortality of Chinese coronary heart disease patients. To exactly explain the clinical features of Xuezhikang, we undertook a complete study of the chemical constituents of Xuezhikang. This study resulted in the isolation of a new monacolin analogue, named alpha, beta-dehydromonacolin L (1), along with two known compounds: monacolin L (2) and 3-(2, 6-dimethyl-1, 2, 4a, 5, 6, 7, 8, 8a-octahydronaphthalen-1-yl)propanoic acid (3). The chemical structures were determined by extensive 1D and 2D NMR and MS spectroscopic analysis.

[The effect of ethylene glycol on the morphology of Cu2O nanoparticles synthesized in w/o microemulsion by gamma-irradiation].

Cuprous oxide nanocubes were successfully prepared in w/o microemulsions by gamma-irradiation in the presence of ethylene glycol (EG). Absorption spectrum, XRD, TEM, HRTEM and SEM were used to characterize the as-prepared nanoparticles. The characteristic peak of Cu2O of absorption spectra of the irradiated microemulsions red-shifts apparently with the EG increasing, showing that the as-prepared Cu2O particle size becomes larger. TEM images verify this point and indicate that Cu2O nanoparticles become uniform with the increase of EG. The results indicated that EG played an important role in the structures of cuprous oxide nanoprticles. Firstly, EG increased the viscosity of water-pools of microemulsions which affected the reactivity of hydrated electrons and finally influenced the reduction of Cu2+ and the precipitation of Cu2O. Secondly, EG reduced the rigidity of the interface of microemulsions and enhanced the mass exchange among water pools which impacted the nucleation and precipitation of Cu2O. Thirdly, EG adsorbed certain crystal faces of Cu2O and influenced the final morphology of Cu2O.

[Investigation on the spectral characteristics and existing state of a substituted 3H-indole molecular probe in triton X-100 reverse micelle].

The interactions between a fluorescent molecular probe, i. e., [2-(p-hexylamino) phenyl-3, 3-dimethyl-5-ethoxycarbonyl-3H-indole] methyldioctadecylammonium iodide (A) and Triton X-100/heptane/hexanol/water reverse micelle have been investigated by spectroscopy. Micropolarity of the environment, fluorescence anisotropy parameter and the pH effect of A in Triton X-100 reverse micelle were determined. Furthermore, the state of water in reverse micellar systems was studied by FTIR. According to the above experimental results, some information on the structure of Triton X-100 reverse micelle was obtained and the probable site of A in this system was discussed.

[Interaction of surface active fluorescence probes and bovine serum albumin].

The binding between two surface-active substituted 3H-indole fluorescence probes, i. e., iodo-dihexadecyl methyl-2-(p-dodecyl amino phenyl)-3, 3-dimethyl-5-carboethoxy-3H-indole ammonium and iodo-dimethyloctadecyl-2-(p-dodecyl amino phenyl)-3,3-dimethyl-5-carboethoxy-3H-indole ammonium, and bovine serum albumin (BSA) in aqueous solution was studied using fluorescence. The binding constant and binding site number of molecule 1 and molecule 2 with BSA were obtained. It was confirmed that electrostatic interaction is the primary driving force for the combination of BSA with molecule 1 or molecule 2. According to the Förster resonance energy transfer theory, the distances between molecule 1, molecule 2 and tryptophan of BSA were calculated to be 2.90 nm and 4.02 nm, respectively.

[Synthesis of substituted 3H-indole quaternary ammonium salt and study on its interaction with bovine serum albumin by fluorescence].

A substituted 3H-indole quaternary ammonium molecule was designed and synthesized using hexamethylphosphoramide (HMPA) as a solvent. The products were purified and characterized by IR, 1H-NMR, MS and elemental analysis. The binding reaction of this compound with bovine serum albumin (BSA) in aqueous solution was studied using fluorescence. Their binding constant is Ka = 1.995 x 10(5) dm3 x mol(-1) and the binding site number is n = 1.12. It is confirmed that the combination is a single static quenching process.

[Studies on the formation of cyclodextrin nanotube by fluorescence and anisotropy measurements].

Steady-state fluorescence and anisotropy measurements have been used to investigate the interaction of 2,2'-biquinoline (BQ) and 1,1'-(methylenedi-1,4-phenylene)bismaleimide (MDP-BMI) with alpha-, beta-, and gamma-cyclodextrins (CDs). It was found that the reaction patterns between fluorescence molecules and CDs are remarkably different. They can form a simple inclusion complex with alpha-CD, while nanotubes can be formed in the presence of gamma-CD. Moreover, MDP-BMI can form nanotube with beta-CD at higher concentration.