Antibacterial activities of the leaf extracts of Eugenia uniflora Linn. (Synonym Stenocalyx michelli Linn.) Myrtaceae

The aqueous, organic, and volatile oil extracts of leaves of Eugenia uniflora Linn. Family Myrtaceae were investigated for antibacterial properties using agar dilution techniques. The aqueous extract was the most active against the organisms compared to the organic and volatile oil extracts. The extracts were found to inhibit Gram positive Staphylococcus aureus and Bacillus subtilis and Gram negative Escherichia coli and Shigella dysentcriae. Pseudomonas aeruginosa, Klebsiella pneumoniac, and Salmonella typhi were not inhibited.     

A specific and sensitive radioimmunoassay for rat C-peptide

A sensitive and specific radioimmunoassay for rat serum C-peptide (RCP) has been developed and validated using a guinea pig anti-rat C-peptide antibody to synthetic rat C-peptide. Negligible crossreactivity (<0.01%) to human proinsulin was observed, whereas human insulin, human pancreatic polypeptide (hPP), porcine insulin, porcine C-peptide, bovine insulin, rat insulin, porcine-PP, and glucagon, respectively, did not produce measurable displacement of RCP tracer. Human C-peptide even in a supraphysiological concentration range crossreacted poorly (<0.1%). The sensitivity limit of the assay calculated at ±3 standard deviations was 24.2pM (0.07 ng/mL). RCP standard concentrations ranged from 25–1600pM. The intraassay-and between assay-coefficient of variations (CV) were 3.5–6.1% and 4.1–9.5%, respectively. The mean percentage recovery of RCP added to rat serum samples was 100.8±2%. Serum volume dilution from 25 to 100 μL did not significantly alter the expected RCP level. Migration of rat serum C-peptide and that of synthetic RCP were identical in a Sephadex G-50 chromatographic analysis. The mean fasting and postprandial plasma RCP levels in normal rats were 102±15pM and 485±75pM, respectively. RCP levels following intravenous glucose tolerance test in diabetic and nondiabetic rats were consistent with expected patterns. In conclusion, we have developed and validated a rat C-peptide assay that is sensitive, simple, and specific for RCP in serum. The assay provides a reliable tool for studies of diabetes using rodent animal models.     

Acridine-based thiosemicarbazones as novel inhibitors of mild steel corrosion in 1 M HCl: synthesis,electrochemical, DFT and Monte Carlo simulation studies

Electrochemical, surface morphology, density functional theory and Monte Carlo simulation methods were employed in investigating the effects of (2E,2′E)-2,2′-(3,3,6,6-tetramethyl-9-phenyl-3,4,6,7-tetrahydroacridine-1,8(2H,5H,9H,10H)-diylidene)bis(N-phenylhydrazinecarbothioamide) (IAB-NP), (2E,2′E)-2,2′-(3,3,6,6-tetramethyl-9-phenyl-3,4,6,7-tetrahydroacridine-1,8(2H,5H,9H,10H)-diylidene)bis(N-(2,4-difluorophenyl)hydrazinecarbothioamide)IAB-ND) and (2E,2′E)-2,2′-(3,3,6,6-tetramethyl-9-phenyl-3,4,6,7-tetrahydroacridine-1,8(2H,5H,9H,10H)-diylidene)bis(N-(2-fluorophenyl) hydrazinecarbothioamide) (IAB-NF) on mild steel corrosion in 1 M HCl solution. From the studies, compounds IAB-NP, IAB-ND and IAB-NF inhibit mild steel corrosion in the acid and the protection efficiencies were found to increase with the increase in concentration of each compound. At the optimum inhibitor concentration of 1.5 × 10⁻⁴ M, the inhibition efficiencies (%) of the compounds are in the order IAB-NF (90.48) > IAB-ND (87.48) > IAB-NP (85.28). Potentiodynamic polarization measurements revealed that all the compounds acted as mixed-type corrosion inhibitors. Experimental data for the adsorption of the studied molecules on a mild steel surface in 1 M HCl fitted into the Langmuir adsorption isotherm and the standard free energies of adsorption (ΔG^o_ads) suggested both physisorption and chemisorption mechanisms. Scanning electron microscopy analyses confirmed the formation of a protective film on the mild steel surface by the inhibitor molecules, resulting in protection of the metal from corrosive electrolyte ions. The experimental findings were corroborated by both theoretical density functional theory and Monte Carlo simulation studies.

Three novel acridine-based thiosemicarbazones were investigated for their corrosion inhibition potentials on mild steel in 1 M HCl using combined electrochemical, DFT and Monte Carlo simulation techniques.     

Effect of Extract of Leaf and Seed of Piper guineense on Some Smooth Muscle Activity in Rat,Guinea-pig and Rabbit

Extracts of the leaf and seed of Piper guineense were separately prepared and their pharmacological effects screened using smooth muscle of the gastrointestinal tract and uterus. The leaf extract enhanced both the frequency and tone of spontaneous contractions of rabbit jejunum and induced contraction of guinea-pig ileum, which were blocked by atropine. The seed extract had the opposite effect on rabbit jejunum, an inhibition which was antagonized by prazocin, and little or no effect on guinea-pig ileum. Both extracts had a stimulant effect on rat uterine muscle, the seed extract to a lesser extent.     

Application, effectiveness, and limitations of the electrophysiological diagnosis of neurotoxic effects of chronic environmental mycotoxins in humans

An extensive body of data demonstrates that diverse groups of mycotoxins can alter the structure and function of the nervous system in a variety of ways with notable human health consequences. Myconeurotoxicity refers to any adverse effects of exposure to mycotoxins or byproducts of primary and secondary mold metabolism, including volatile organic compounds (VOCs) on the structural or functional integrity of the developing or adult nervous system. Neuromycotoxic effects may involve a spectrum of biochemical, morphological, behavioral, and physiological abnormalities whose onset can vary from immediate to delayed action, following exposure to a mycotoxin, and whose duration may be transient or persistent and result in disability, while some may have life-threatening consequences. Myconeurotoxicity may result from effects of the mycotoxins acting directly on the elements of the nervous system or acting on other biological systems, which then adversely affect the nervous system. This paper reviews the application, effectiveness, and limitations of the electrophysiological diagnosis of myconeurotoxic effects of chronic environmental exposure to mycotoxins. The systemic targets of mycotoxic effects were reviewed for greater understanding as to why different neurophysiological test techniques have different levels of outcomes. Thus, nerve conduction velocity, sensory, motor, and evoked potentials, electroencephalographic techniques were evaluated using previously published papers and our clinical experience. Although, neuromycotoxic disorders can be established using clinical electrophysiological diagnosis, there is always the possibility of false positive and false negative results in some patients, which may be due to a multi-factorial etiopathogenesis of neuromycotoxicity. Detection of nervous system toxicity and other measures of toxicity could be achieved using a combination of these neurodiagnostic techniques.     

Antimalarial potency of the leaf extract of Aspilia africana (Pers.) C.D. Adams

ObjectiveTo investigate the antimalarial activity of ethanol extract of Aspilia africana (A. africana) leaf.MethodsThe ethanol extract of A. africana leaf (100–400 mg/kg) was screened for blood schizonticidal effect against chloroquine-sensitive Plasmodium berghei (P. berghei) in mice both in early and established models of antimalarial studies.ResultsThe leaf extract exhibited significant (P<0.05) antiplasmodial activity in 4-day early infection and in established infection tests with a considerable mean survival time comparable to that of standard drug, chloroquine (10 mg/kg).ConclusionsThe findings show that ethanol extract of A. africana leaf possesses potent antiplasmodial activity which justify the use in ethnomedicine and can be developed in malaria therapy.     

Antiplasmodial and antipyretic studies on root extracts of Anthocleista djalonensis against Plasmodium berghei

ObjectiveTo evaluate the antimalarial activities of ethanolic root extract/fractions of Anthocleista djalonensis (A. djalonensis) in Plasmodium berghei (P. berghei) infected mice.MethodsA. djalonensis root extract (175–1 000 mg/kg) and fractions (chloroform, ethyl acetate and methanol; 250 and 500 mg/kg) were investigated for antiplasmodial activity against chloroquine-sensitive Plasmodium berghei infections in mice and for antipyretic activity against dinitrophenol, amphetamine and yeast-induced pyrexia. The antiplasmodial activity during early and established infections as well as prophylactic were investigated. Artesunate (5 mg/kg) and pyrimethamine (1.2 mg/kg) were used as positive controls. Antipyretic activity of the crude extract was also evaluated against dinitrophenol, amphetamine and yeast-induced pyrexia.ResultsThe extract and its fractions dose-dependently reduced parasitaemia induced by chloroquine sensitive Plasmodium berghei infection in prophylactic, suppressive and curative models in mice. These reductions were statistically significant (P<0.001). They also improved the mean survival time from 13 to 28 days relative to control (P<0.001). The activities of extract/fractions were comparable to that of the standard drugs used (chloroquine and pyrimethamine). On pyrexia induced by dinitrophenol, amphetamine and yeast, the extract inhibited significantly (P<0.05 – 0.001) and in a dose-dependent fashion temperature rise caused by these pyrogens.ConclusionsA. djalonensis root extract has antiplasmodial and antipyretic activities which may in part be mediated through the chemical constituents of the plant.     

Home medication and microbiological profile in chronic otitis media in some Nigerian children

The relationship of home medication to the pathology and microbiological profiles of chronic otitis media was studied in 135 children with middle ear infections. Middle ear lesions were examined and sample obtained for microscopy and culture for bacterial and fungal pathogens. Of a total 115 patients who received home treatment, mostly with extracts of a local herb, Cleome ciliata and unprescribed antibiotics, 111 (96.5 pc) had chronic otitis media with purulent effusion (OME), compared with 11 (55 pc) otitis media (OM) cases among 20 patients who had not received such treatments (p less than 0.05). Staphylococcus aureus and Pseudomonas spp. were the predominant isolates; the latter were the sole infecting agents in 41 episodes and occurred in 10 co-infections. Sensitivity pattern of bacterial isolates indicated that a large proportion of infections would respond to empiric treatment with gentamicin in anticipation of laboratory results on sensitivity tests. This report suggests further studies to define the significance of these medications in the pathogenesis of chronic OME in Nigerian children.