The Effect of Dielectric Constant On The Kinetics of Reaction Between Plasma Albumin And Formaldehyde In Ethanol- Water Mixtures.

This study determined the effect of increased concentration of ethanol solution on the rate of the reaction between plasma albumin and formaldehyde. It was design to investigate the kinetics of reaction between plasma albumin and low concentrations of formaldehyde  under  pseudo-first order conditions of formaldehyde. The reaction was studied at constant conditions at various dielectric constants and temperatures of   1%, 5%, 15%,20% and 200C  250C, 300C  and 370C respectively. The rate constant as a function of different permittivity in ethanol-water  mixtures  was  determined at constant  conditions.  The dielectric constant of the reaction medium was altered by the addition of the varying amounts of  ethanol  – water mixtures (1- 25% v/v) in a cuvette  and  the absorption  of  0.51 x10-4 mol dm-3 plasma albumin and 0.27 x10-1 formaldehyde- plasma  mixtures  at 235 nm were measured. The values of dielectric constants for different aqueous ethanol- mixtures were taken from literature. The values of rate constants of the reaction of between plasma albumin and formaldehyde were found to decreased with the increase in the concentration of ethanol and the reaction was a second order or bimolecular . The Activation energy and  the  thermodynamic parameters (Gibbs free energy, enthalpy and entropy changes of the reaction)  decreased with  decrease  in dielectric constant of the  medium, that is with  increase in the proportion of the ethanol component  in the solvent mixtures.   The dependence of lnk2 vs. reciprocal dielectric constant (1/D ) of this reaction was found  be linear  with  three  linear portions indicating three zones, that is  three mechanistic changes. Also the correlations between lnk2 and the mole fractions of water and ethanol  ( ?H2O and  ?EtOH) have  shown  that there  was  an increase in rate of the studied reaction in  water but a  decrease  in rate in ethanol mole  fraction.  This leads us to suggest that the reaction rates were slowed by progressive addition of ethanol . A steady decrease in rate constant with decrease in dielectric constant values was observed with a statistically significant p-value =  0.0013 on a two tailed correlation analysis  at 95% confidence assurance. Key Words; dielectric constant, kinetics ,  plasma albumin,   formaldehyde ,   ethanol- water mixtures.

Preliminary studies on the behavioural effects of the methanol extract of Leonotis nepetifolia Linn stem in mice

Background: Leonotis nepetifolia Linn (Lamiaceae) is used in traditional medicine for its calming (tranquilizing) effects. The aim of this study was to determine whether there is any scientific justification for this use. To achieve this purpose, we investigated the behavioural effects of the methanol extract of Leonotis nepetifolia stem (37.5, 75 and 150 mg/kg) in mice.Methods: Acute toxicity studies were carried out on the methanol stem extract of Leonotis nepetifolia to determine the LD50. The behavioural tests employed were diazepam-induced sleep onset and duration, hole board assay for exploratory activity, mouse beam walk assay for motor coordination, and the staircase test for the detection of anxiolytic compounds. Preliminary phytochemical screening was also carried out on the extract.Results: The intraperitoneal LD50 value was found to be 3.8 g/kg. The results showed that the extract significantly prolonged the duration of diazepam-induced sleep at the highest dose (150 mg/kg). There was no observable effect on exploratory activity and motor coordination at the doses tested (37.5, 75 and 150 mg/kg). The extract, however, at 150 mg/kg elicited a significant decrease in the number of rearings in the staircase test, an effect also observed in the group of mice injected with an anxiolytic dose of diazepam. The preliminary phytochemical  screening revealed the presence of alkaloids, saponins, glycosides and   triterpenoids.Conclusion: The results obtained suggest that the crude methanol extract of Leonotis nepetifolia stem possesses some biologically active constituents with potential anxiolytic activity and thus may justify its traditional use as a tranquilizer.Keywords: behavioural; exploratory; Leonotis nepetifolia; motor coordination; anxiolyti

PRELIMINARY STUDIES ON THE BEHAVIOURAL EFFECTS OF THE METHANOL EXTRACT OF LEONOTIS NEPETIFOLIA LINN STEM IN MICE

Background: Leonotis nepetifolia Linn (Lamiaceae) is used in traditional medicine for its calming (tranquilizing) effects. The aim of this study was to determine whether there is any scientific justification for this use. To achieve this purpose, we investigated the behavioural effects of the methanol extract of Leonotis nepetifolia stem (37.5, 75 and 150 mg/kg) in mice. Methods: Acute toxicity studies were carried out on the methanol stem extract of Leonotis nepetifolia to determine the LD50. The behavioural tests employed were diazepam-induced sleep onset and duration, hole board assay for exploratory activity, mouse beam walk assay for motor coordination, and the staircase test for the detection of anxiolytic compounds. Preliminary phytochemical screening was also carried out on the extract. Results: The intraperitoneal LD50 value was found to be 3.8 g/kg. The results showed that the extract significantly prolonged the duration of diazepam-induced sleep at the highest dose (150 mg/kg). There was no observable effect on exploratory activity and motor coordination at the doses tested (37.5, 75 and 150 mg/kg). The extract, however, at 150 mg/kg elicited a significant decrease in the number of rearings in the staircase test, an effect also observed in the group of mice injected with an anxiolytic dose of diazepam. The preliminary phytochemical screening revealed the presence of alkaloids, saponins, glycosides and triterpenoids. Conclusion: The results obtained suggest that the crude methanol extract of Leonotis nepetifolia stem possesses some biologically active constituents with potential anxiolytic activity and thus may justify its traditional use as a tranquilize

base extract

The neuropharmacological effects of aqueous methanolic extract of leaf base of Sorghum bicolor were studied on Wistar rats and Swiss albino mice; evaluations were done on spontaneous motor activity, exploratory behaviour, apomorphine-induced stereotypic behaviour, pentobarbitone sleeping time and rota-rod performance for motor coordination. The results showed a significant (P < 0.05) reduction in the spontaneous motor activity. The treated animals exhibited: (i) A reduction in the exploratory behaviour as did diazepam (1 mg/kg i.p.); (ii) No change in Apomorphine-induced stereotypic behaviour; (iii) Prolonged pentobarbitone-induced sleep as did diazepam (1 mg/kg i.p.) and cimetidine (100 mg/kg p.o) and no significant (P < 0.05) effect on rota-rod performance for motor coordination. These findings suggest that leaf base extracts of S. bicolor contains sedative substances that act via centrally-mediated actions rather than peripheral neuromuscular blockade and may also be microsomal enzyme inhibitor like cimetidine. Key words: Sorghum bicolor, spontaneous motor activity, exploratory behaviour, stereotype behaviour, pentobarbitone sleep, motor coordination

Distribution of Virulence Genes in <em>Salmonella</em> Serovars isolated from poultry farms in Kwara State, Nigeria

This study was aimed at investigating the prevalence and detection of virulence genes in Salmonella isolated from poultry farms in Kwara State, Nigeria. Ten commercial layer farms located in three senatorial districts of the state were sampled. The presence of Salmonella was investigated using standard bacteriological techniques, the isolates obtained were serotyped and polymerase chain reaction (PCR) was used to detect presence of two genes (fimA and sefC) in the isolates. Of the 300 samples collected, 24 (8.0%) were positive for Salmonella; 4 different serovars were identified; Salmonella Larochelle, S. Muenster, S. enterica ser. 6, 7:d, S. enterica ser. 45:d:1,7 and Salmonella Typhimurium, the most frequent being Salmonella Typhimurium (3%). Varying distribution patterns of the studied genes were observed among the isolates. While, fimA was found in all the 24 (100%) isolates, sefC was found only among the Salmonella enterica ser. 45: d: 1,7. The study indicates that the fimA gene is widely distributed among Salmonella irrespective of the serovars. However, the sefC gene appears to be serovar specific. The prevalence of Salmonella in chicken and poultry farms constitutes a major public health concern. Hence, further epidemiological studies are necessary