Kinetics of Autoxidation of an Oil Extract from Terminalia catappa.

Soxhlet extractor was used in the extraction of oil from milled seeds of Terminalia catappa using petroleum ether (40-60 degrees ). The optimal oil yield was 56.71+/-1.66% with a viscosity of 40.79+/-1.05 centipoises. Other parameters of the oil were found as follows; specific gravity-0.9248, refractive index-1.4646, acid value-3.35, peroxide value-8.6, saponification value-166.2, and unsaponifiable matter-1.46. The crude oil extract was water-degummed, bleached and deodorized to generate what we called refined oil. Autoxidation of the crude and refined T. catappa oil extract was done at five different temperatures of 0+/-0.1 degrees , 20+/-0.1 degrees , 40+/-0.1 degrees , 60+/-0.1 degrees and 80+/-0.1 degrees and also in the presence of pure alpha-tocopherol at a concentration of 1.0% (w/v) by measuring peroxide value variations over 96 h. In all evaluations, the refined oil exhibited lower tendency towards autoxidation but not at temperatures above 60+/-0.1 degrees . The use of Arrhenius equation revealed generally very low activation energies of 0.0261 cal/degxmol and 0.0122cal/degxmol for crude oil and antioxidant-treated crude oil, respectively and 0.0690 cal/degxmol and 0.0177 cal/degxmol for the refined oil. This study indicates T. catappa seed oil to be potential pharmaceutical oil with excellent characteristics.

Antimicrobial activity of Securidaca longipedunculata.

The folk herbal uses of Securidaca longipedunculata in the treatment of diarrhea, boils, gonorrhea, and cough prompted phytochemical analyses and antimicrobial activity screening of extracts of the root. Some flavonoids isolated showed activity against many micro-organisms. These flavonoids were isolated using chromatographic methods.

Better biosynthesis of ergot alkaloids.

Different culture media containing different effectors for production of ergot-alkaloids were prepared. The culture media were inoculated with equal mycelia of Claviceps purpurea and some were incubated for 22 days and some incubated for 45 days. The medium that contained a mixture of glucose, glycine and tryptophan showed highest yield of the alkaloids and reached the maximum period for production of agroclavine faster.

Detection of alpha-methyldopa on thin-layer plates using pi-acceptors in 1,4-dioxane.

pi-Acceptors (P-chloranil and chloranilic acid) in 1,4-dioxane were used to detect alpha-methyldopa on thin layer plates. Thin layer plates coated to a thickness of 0.25 mm with silica gel G60 were spotted with solution of alpha-methyldopa from drug formulations and pure alpha-methyldopa solution. The plates were developed in a solvent system of methanol: glacial acetic acid: water (14:5:3). The developed plates were dried and sprayed with pi-acceptors, and further were counter-sprayed with dimethylformamide (DMF). P-Chloranil gave an immediate blue green complex with alpha-methyldopa which intensified on counter-sprayed with DMF. alpha-methyldopa (reference sample and those from drug formulations) gave Rf of 0.85 and excipients from the drug formulations did not interfere with the result.

Spectrophotometric determination of nikethamide by charge--transfer complexation with chloranilic acid.

A Spectrophotometric method is described for assay of nikethamide which was based on charge transfer complexation between it and chloranilic acid. They form a complex with stoichiometric ratio of 1:1 and showed l-max at 535 nm. Maximum complexation occurred 30 min after mixing the reactants and was stable for 12 hr. The molar absorptivity, association constant and free energy for the complex were 1.05 x 1.0(2), 4.40 x 10(-2) litre mole-1 and 1819.02 kcal respectively. Conformity to Beer's Law was within the concentration range of 1-2.5 x 10(-4), which enabled the assay of dosage forms of the drug at microquantities.

Quantitative determination of famotidine through charge-transfer complexation with chloranilic acid.

Quantitative determination of famotidine and its dosage forms was carried out spectrophotometrically, analysing the coloured complex resulting from a charge-transfer interaction between the drug as an electron-donor and chloranilic acid as an electron-acceptor. Famotidine-Chloranilic acid complex displayed l-max at 5 25 nm. Conditions and time for complex formation have been optimized. The stoichiometry of the complex is 3:2 donor to acceptor mole ratio. Calibration graph of the complex was found to be linear at a working concentration range of 1.60-11.g% (w/v). Excellent quantitative recoveries (99.01-100.71%) was obtained for the drugs in both its pure and standard dosage forms.

Chromatographic detection of captopril using 4-dimethylaminobenzaldehyde as spray reagent.

Thin layer chromatographic method, using a mixture of acetone:ethanol in the ratio of 9:1 as a developing solvent system, was used to detect captopril in its formulation. The developed chromatogram was sprayed with 4-dimethylaminobenzaldehyde. The product formed by reaction of captopril with 4-dimethylaminobenzaldehyde gave a yellow colour. Rf of captopril is 0.56.

Spectrophotometric and some thermodynamic parameters of the charge transfer complexation between chloranilic acid and chlorpheniramine.

The principle of charge transfer complexation involving a pi-acceptor (chloranilic acid) and an n-donor (chlorpheniramine) was utilized in the assay of the later in its pure form and in its tablet dosage forms. Some thermodynamic parameters of the complex such as association constant (Kc), molar absorptivity (epsilon c), free energy change (delta G degree), enthalpy (delta H degree) and entropy (delta S degree) changes were determined to establish the stability of the complex and the optimum conditions for the complex formation. The values obtained for these thermodynamic parameters indicated that the complex formed between this two chemical entities is highly stable. Assay of chlorpheniramine in its pure form and in its tablet dosage forms gave high percentage recoveries. The principle of charge transfer complexation could therefore be employed in the colorimetric assay of chlorpheniramine in its tablet dosage forms.

Antibacterial activity of Alchornea cordifolia stem bark.

The results of a preliminary antimicrobial screening of the petroleum ether, acetone, ethanol and methanol successive extracts of Alchornea cordifolia stem bark are reported.

Antibacterial activity of Enantia polycarpa bark.

Antimicrobial screening of Enantia polycarpa bark showed activity of the polar extracts against some microorganisms.

Chromatographic detection of cimetidine and famotidine using chloranilic acid as a spray reagent.

Qualitative determination of cimetidine and famotidine by TLC using chloranilic acid as the detecting spray reagent was carried out in different elution systems. On spraying, coloured spots corresponding to the drugs were formed which were stable for over three hours. In a particular solvent system, a commercial sample gave the same Rf value as its corresponding pure reference sample without any interference from the excipient.