Inhibitors of prostaglandin biosynthesis from Dalbergia odorifera.

The root heartwood of Dalbergia odorifera T. Chen (Leguminosae) is a Chinese medicinal drug (Japanese name koshinko) used for a stagnant blood syndrome (stagnation of disordered blood; Japanese, oketsu). In addition to 10 known compounds, five new phenolic compounds, isomucronustyrene and hydroxyobtustyrene (cinnamylphenols), (+)-isoduartin (isoflavan), odoriflavene (isoflav-3-ene) and (-)-odoricarpan (pterocarpan) were isolated and their structures were elucidated on the basis of chemical and spectroscopic methods. Of the fifteen compounds isolated, cinnamylphenols, isoflavans, isoflavene and benzoic acid derivative significantly inhibited prostaglandin biosynthesis as well as platelet aggregation induced by arachidonic acid.     

Validation of a method for predicting the precision, limit of detection and range of quantitation in competitive ELISA.

The mathematical model for predicting the precision, limit of detection (LOD) and range of quantitation (ROQ) in a competitive enzyme-linked immunosorbent assay (ELISA) proposed by Hayashi et al. (Anal. Chem., 2004, 76, 1295) was validated. The model describes the relative standard deviation (RSD) of concentration estimates by the RSDs of pipetting volumes of analyte, enzyme-conjugated antigen, antibody and substrate solutions, and the standard deviation (SD) of inherent absorbances between the wells in an ELISA plate. For 6 kinds of direct competitive ELISA kits, the LOD and ROQ predicted by the model agreed well with those obtained by experiments with real samples. It was also confirmed that the model is applicable to the prediction of uncertainty that depends on the pipetting error of the viscous antiserum solution. The model was demonstrated to be useful for estimating the LOD and ROQ of competitive ELISA.     

Pharmacokinetics of the nitroxide PCA measured by in vivo EPR

PCA (2,2,5,5-tetramethylpiperidine-1-oxyl-3-carboxylic acid) is a relatively stable free radical which has been shown to be useful as a contrast agent for nuclear magnetic resonance imaging and as an imaging/spectroscopy agent for EPR. In an effort to determine the role of the liver and kidney in the pharmacokinetics of PCA, using low frequency in vivo EPR spectroscopy, we followed the clearance of PCA after intravenous injection in mice: under normal conditions, with a restricted blood supply to the kidneys, after exposure to an acute hepatotoxin CCl₄, and after exposure to lipopolysaccharide (endotoxin). The observed pharmacokinetics fit a two-component model. The fast component was dramatically affected when the renal vessels were restricted, while CCl₄ and endotoxin had a smaller but significant effect. The half times of the slow components were not significantly different (p>0.05) in the groups treated by renal blood flow occlusion, CCl₄, or LPS, compared with the control group. In conclusion, we find that the pharmacokinetics of PCA need to be completely described in term of a two component model: the fast component of the decay is mainly due to the elimination by the kidneys and also is affected by the time for the initial distribution; the slow component is related to the bioreduction of the nitroxide. In addition to the liver other tissues can also effectively metabolize PCA. The effect of oxygen on the rate of metabolism is modest at most.     

The mutagenic constituents of Rubia tinctorum.

Twenty compounds were isolated from the roots of Rubia tinctorum which are used as a commercial source of madder color. Among these compounds, mollugin (1), 1-hydroxy-2-methylanthraquinone (2), 2-ethoxymethylanthraquinone(11), rubiadin (13), 1,3-dihydroxyanthraqunone (14), 7-hydroxy-2-methylanthraquinone (16), lucidin (17), 1-methoxymethylanthraquinone (18) and lucidin-3-O-primeveroside (19) showed mutagenicity with Salmonella typhimurium TA 100 and/or TA 98. Since the mutagenic compounds isolated are anthraquinone derivatives with the exception of compound 1, structure-mutagenicity relationships of the anthraquinones were also studied. The results suggested that the greatest activity is exhibited by 1,3-dihydroxyanthraquinones possessing methyl or hydroxylmethyl group on carbon 2.     

(Z)-3-p-tolylsulfinylacrylonitrile as a chiral dienophile: diels-alder reactions with furan and acyclic dienes

The behavior of (Z)-3-p-tolylsulfinylacrylonitrile (1) as a chiral dienophile has been evaluated from its reactions with furan and acyclic dienes. Electrostatic interactions of the cyano group with the sulfinyl one restrict the conformational mobility around the C-S bond, thus controlling the pi-facial selectivity, which is almost complete in all cases, the approach of the diene from the less-hindered face of the dienophile (that bearing the lone electron pair) in the predominant rotamer being the favored one. The regioselectivity is also completely controlled by the cyano group. Additionally, the reactivity of compound 1 as well as its endo-selectivity are both higher than those observed for the corresponding (Z)-3-sulfinylacrylates, thus proving the potential of sulfinylnitriles as chiral dienophiles.     

Narrow band quantitative and multivariate electroencephalogram analysis of peri-adolescent period

ABSTRACT: BACKGROUND: The peri-adolescent period is a crucial developmental moment of transition from childhood to emergent adulthood. The present report analyses the differences in Power Spectrum (PS) of the Electroencephalogram (EEG) between late childhood (24 children between 8 and 13 years old) and young adulthood (24 young adults between 18 and 23 years old). RESULTS: The narrow band analysis of the Electroencephalogram was computed in the frequency range of 0--20 Hz. The analysis of mean and variance suggested that six frequency ranges presented a different rate of maturation at these ages, namely: low delta, delta-theta, low alpha, high alpha, low beta and high beta. For most of these bands the maturation seems to occur later in anterior sites than posterior sites. Correlational analysis showed a lower pattern of correlation between different frequencies in children than in young adults, suggesting a certain asynchrony in the maturation of different rhythms. The topographical analysis revealed similar topographies of the different rhythms in children and young adults. Principal Component Analysis (PCA) demonstrated the same internal structure for the Electroencephalogram of both age groups. Principal Component Analysis allowed to separate four subcomponents in the alpha range. All these subcomponents peaked at a lower frequency in children than in young adults. CONCLUSIONS: The present approaches complement and solve some of the incertitudes when the classical brain broad rhythm analysis is applied. Children have a higher absolute power than young adults for frequency ranges between 0-20 Hz, the correlation of Power Spectrum (PS) with age and the variance age comparison showed that there are six ranges of frequencies that can distinguish the level of EEG maturation in children and adults. The establishment of maturational order of different frequencies and its possible maturational interdependence would require a complete series including all the different ages.     

Green synthesis of bio-ethyl acetate over Egyptian natural red clay as a highly active,selective, and eco-friendly catalyst

The present work focused on the utilization of Egyptian red clay (ERC) without any treatment as a highly efficient, selective, and eco-friendly catalyst for synthesis of bio-ethyl acetate in the gas phase. The best conditions used in conventional fixed bed reactor were 130 cm³/min total flow rate of air with 1.6 and 2.1 vol% bio-ethanol and bio-acetic acid, respectively, 1 g clay catalyst calcined at 300 and 225°C reaction temperature. Under these conditions, the conversions to ester achieved were about 80 and 98% after 5 and 30 min, respectively, from the initial admission of the reactants into the reactor. The amount and type of surface acidity were identified by isopropanol reaction and chemisorption of basic probes. The results demonstrated that the majority of intermediate strength of BrØnsted acid sites are the key role for the dehydration reaction toward ester formation. The virgin and annealed clay solids were characterized using X-ray fluorescence (XRF), thermogravimetry (TG) and differential thermal analysis (DTA), Fourier transform infrared (FTIR), X-ray diffraction (XRD), and N₂ sorption.     

Characterization and catalytic performance of basaltic dust as an efficient catalyst in the liquid‐phase esterification of acetic acid with n‐butanol

Three natural basaltic samples were collected and used as efficient catalysts for the liquid‐phase synthesis of n‐butyl acetate. The samples were characterized by X‐ray fluorescence analysis (XRF), X‐ray diffraction (XRD), thermogravimetry (TG), differential thermal analysis (DTA), Fourier transform infrared (FT‐IR), scanning electron microscopy (SEM), and N₂ sorption. The acidity of the samples was determined using isopropanol dehydration, and the strength of the acid sites was measured using chemisorption of basic probes. The catalytic activity of the samples towards the esterification of acetic acid with n‐butanol was extensively examined. The influence of different parameters, such as the reaction refluxing time, molar ratio, catalyst loading, reusability, and calcination temperature, on the esterification reaction was studied in detail. The results revealed that all samples had high catalytic activity with a selectivity of 100% to n‐butyl acetate formation. In addition, the sample obtained from the top hill of Volcano had the highest activity with a 80% yield of n‐butyl acetate. Moreover, the significant catalytic performances were well correlated with the acidity of the samples and to the reaction rate constants.