Gn Thoithi

Essential oil of hyptis suaveolens(L)poit.from Tanzania composition and antifungal activity

Abstract The hydrodistilled essential oil (yield 1.2%) of fresh leaves of wild Hyptis suaveolens (L.) Poit. was analyzed by GC/MS. Twenty-four compounds representing 90.3% of the oil were identified. The main components of the oil were β-caryophyllene (26.0%), β-elemene (10.4%), trans-α-bergamotene (7.7%), spathulenol (7.0%) and bicyclogermacrene (6.5%). The oil exhibited significant antimicrobial activity against Mucor sp. when compared to ketoconazole.

Epoxychiromodine and other constituents of Croton megalocarpus

Abstract A novel clerodane-type diterpene with a 6,7-oxirane group has been isolated from Croton megalocarpus. Structure elucidation has been achieved by a combination of spectroscopic measurements including 2D NMR and NOE experiments. In addition, 3-O-acetoacetyl lupeol, a novel triterpene ester, the triterpene O-acetyl aleuritolic acid, and long chain esters of E-ferulic acid with C24-, C26- and C28-alcohols were also isolated and characterized by spectroscopic methods.

Quantitative analysis of quaternary ammonium antiseptics using thin-layer densitometry

A thin-layer chromatography method for quantitative analysis of quaternary ammonium antiseptics is described. Silanized silica gel was used as the stationary phase. The mobile phase consisted of methanol-25% (m/v) sodium acetate solution-acetone (65:35:20). The method is able to separate the chain homologues of benzalkonium chloride, cetylpyridinium chloride and cetrimide. Detection was performed using a colour reaction with potassium triiodide solution. The different homologues were quantified using UV densitometry at 400 nm. A number of commercial samples was analysed using this method. From the results it appears that it is worthwhile to have a limit test for the composition of quaternary ammonium antiseptics in pharmacopoeial monographs, the more so as the antibacterial activity depends on it.

Evidence review of hydroxyurea for the prevention of sickle cell complications in low-income countries

Hydroxyurea is widely used in high-income countries for the management of sickle cell disease (SCD) in children. In Kenyan clinical guidelines, hydroxyurea is only recommended for adults with SCD. Yet many deaths from SCD occur in early childhood, deaths that might be prevented by an effective, disease modifying intervention. The aim of this review was to summarise the available evidence on the efficacy, effectiveness and safety of hydroxyurea in the management of SCD in children below 5 years of age to support guideline development in Kenya. We undertook a systematic review and used the Grading of Recommendations Assessment, Development and Evaluation system to appraise the quality of identified evidence. Overall, available evidence from 1 systematic review (n=26 studies), 2 randomised controlled trials (n=354 children), 14 observational studies and 2 National Institute of Health reports suggest that hydroxyurea may be associated with improved fetal haemoglobin levels, reduced rates of hospitalisation, reduced episodes of acute chest syndrome and decreased frequency of pain events in children with SCD. However, it is associated with adverse events (eg, neutropenia) when high to maximum tolerated doses are used. Evidence is lacking on whether hydroxyurea improves survival if given to young children. Majority of the included studies were of low quality and mainly from high-income countries. Overall, available limited evidence suggests that hydroxyurea may improve morbidity and haematological outcomes in SCD in children aged below 5 years and appears safe in settings able to provide consistent haematological monitoring.

Essential oil of cymbopogon winterianus jowitt from Tanzania: Composition and antimicrobial activity

Abstract The hydro-distilled essential oil (1.6%) of fresh aerial parts of wild Cymbopogon winterianus Jowitt was analyzed by GC-MS. Fifty compounds representing 96.5% of the oil were identified. The main components of the oil were linalool (27.4%), citronellol (10.9%), geraniol (8.5%), α-calacorene, cis-calamenene (4.3%), β-elemene (3.9%) and longifolene (3.5%). The oil exhibited low antimicrobial activity.

Sub-acute toxicity of the chloroformic extract of Rapanea melanophloeos (L.) Mez in rats

ETHNOPHARMACOLOGICAL RELEVANCE Cape beech (Rapanea melanophloeos) is an important medicinal plant that is widely used in most of Africa. Currently, little toxicological information is available on its safety following prolonged use. AIM OF THE STUDY In this study, we sought to evaluate the oral sub-acute toxicity of Rapanea melanophloeos stem bark chloroformic extract using Sprague Dawley rats. MATERIALS AND METHODS Six-week old rats were orally administered with the extract at dosage levels of 100 mg/kg, 300 mg/kg and 1000 mg/kg for 28 days. Clinical signs, hematological and clinical chemistry parameters were monitored, while organ weights and organ pathology were evaluated at the end of the study. RESULTS The extract caused a significant reduction in bodyweight at 1000 mg/kg. The hematological profiles of animals at this dose showed an increase in the erythrocyte count and the hematocrit that were accompanied by decrease in the mean corpuscular hemoglobin and mean corpuscular hemoglobin concentration. Biochemical parameters were not altered in a dose-related manner when compared to the controls. There were time associated alterations on both hematological and biochemical parameters, but pathological examination did not reveal any treatment related changes in any of the organs. CONCLUSION Our results demonstrate that the chloroformic stem bark extract of Rapanea melanophloeos may be of no toxicological concern at dosage levels up to 1000mg/kg. Rapanea melanophloeos can therefore be used confidently in African traditional medicine at these or lower dosage levels.

Investigation of the kinetics of degradation of hexopyranosylated cytosine nucleosides using liquid chromatography

Abstract Liquid chromatography was used to follow the degradation of hexopyranosylated cytosine nucleosides in buffers of acid, neutral and alkaline pH and of constant ionic strength. The compounds were found to degrade by hydrolysis to cytosine and/or by deamination to the corresponding uracil nucleosides. Degradation in acid is influenced by the number of sugar hydroxyl groups, presence of sugar double bonds and the type of anomer. Stability of some of the compounds was compared with that of related thymine nucleosides. Temperature studies support a unimolecular mechanism of hydrolysis at pH 1.22.

A liquid chromatography method for simultaneous determination of diphenhydramine, promethazine, chlorpheniramine and ephedrine in cold-cough syrups

Asimple, rapid isocratic liquid chromatography method was developed for the simultaneous determination of diphenhydramine, promethazine, chlorpheniramine, and ephedrine in cold-cough syrups commonly available in the Kenyan market. The influence of the percentage of organic modifier, ion pairing agent, buffer concentration as well as pH and column temperature on the selectivity with respect to analytes was investigated. Optimum chromatographic separation was achieved using a C18 Gemini® NX column (250 mm × 4.6 mm, 5 μm) maintained at 40°C and a mobile phase comprising methanol – triethylamine – 0.2 M ammonium acetate pH 5.0 – water mixture (50 : 0.15 : 40 : 9.85, v/v) delivered at a flow rate of 1.0 mL/min. Upon validation, the proposed liquid chromatography method satisfied the International Committee on Harmonization acceptance criteria for linearity, sensitivity, precision, and robustness. The method was applied in the analysis of commercial samples obtained from Nairobi County, Kenya. The method can be used in routine analysis of cold-cough syrups containing the specified compounds.

Essential oil of Rynchosia minima DC. from Kenya : Composition and antibacterial properties

Abstract The hydrodistilled essential oil (yield, 0.1%) of semi-dried leaves of Rynchosia minima DC. was analyzed by GC and GC/MS. Twenty-four compounds representing 95.9% of the oil were identified. The major components were found to be β-caryophyllene (30.4%), germacrene B (17.9%), camphor (7.8%), α-humulene (7.4%) and γ-muurolene (7.3%). The oil was found to exhibit antibacterial activity against Bacillus cerus, Staphylococcus aureus and Micrococcus luteus.

Liquid chromatographic separation of hexopyranosylated cytosine nucleosides from their degradation products

Development of a liquid chromatographic method which can separate each of a series of hexopyranosylated cytosine nucleosides from their degradation products formed at acid, neutral and basic pH is described. Both silica-based reverse-phase and polymer columns were examined. Influence of the mobile phase pH, ion-pairing agent, concentration of the buffer and type and concentration of organic modifier were systematically investigated. The concentration of the ion-pairing agent and the buffer were found to have a major effect on selectivity. Samples were finally analyzed on a poly(styrene-divinylbenzene), PLRP-S 100 A (8 microns) 250 x 4.6 mm I.D. column at 60 degrees C and with a mobile phase consisting of acetonitrile-sodium octanesulphonate (pH 2.5; 0.02 M)-potassium phosphate buffer (pH 2.5; 0.2 M)-water (X:25:50:25-X, v/v, where X is variable).