Mohamed S. Karawya

Isolation of triterpene saponins from Gypsophila capillaris

Four novel triterpenoid saponins have been isolated from Gypsophila capillaris. Three were monodesmosidic: 3 beta-hydroxyolean-12-en-23,28-dioic acid 28-O-[beta-D-glucopyranosyl-(1-->3)-beta-D-glucopyranosyl-(1-->2)] [beta-D-galactopyranosyl(1-->6)]beta-D-glucopyranoside, 3 beta-hydroxyolean-12-en-23-oxo-28-oic acid 28-O-[beta-D-glucopyranosyl-(1-->2)-beta-D-galactopyranosyl-(1-->3)] [beta-D-glucopyranosyl(1-->6)]beta-D-galactopyranoside, 3 beta-hydroxyolean-12-en-23,28-dioic acid 28-O-[beta-D-glucopyranosyl-(1-->2)-beta-D-galactopyranosyl-(1-->3)] [beta-D-glucopyranosyl(1-->6)]beta-D-galactopyranoside. The fourth was bisdesmosidic: 3 beta-hydroxyolean-12-en-23,28-dioic acid 23-O-beta-D-glucopyranosyl-28-O-[beta-D-glucopyranosyl-(1-->2)-beta-D- galactopyranosyl-(1-->3)][beta-D-glucopyranosyl-(1-->6)]beta-D- galactopyranoside. The structures of the compounds were elucidated by 1D and 2D NMR techniques and from other spectroscopic evidence.

Study of Essential Oil of Artemisia monosperma and its Larvicidal Effect

AbstractThe steam distilled oil of the overground parts of Artemisia monosperma was analysed by chromatographic and spectral techniques. The oil was found rich in dibenzofuran (36%), 1-phenyl-bicyclo [3.3.1] non-2-en-9-ol benzoate (25%) and octahydrophenanthrene (12%). It contains also diphenylamine (2%) which is a strong hypoglycemic. The biological study revealed that the oil possesses a larvicidal effect which is mainly due to the presence of dibenzofuran.

Colorimetric Assay of Caffeine in Crude Drugs and in Pharmaceutical Preparations

Abstract The well known Hurexide reaction for purine bases was modified and optimized for the quantification of caffeine in crude drugs, refreshing drinks and pharmaceuticals. The method was also applied for the detection and assay of caffeine in mixtures of illegal opiate samples. It was also applied to assay theobromine and theophylline alongside with caffeine in their natural and synthretic mixtures after a simple separating procedure depending on their different basicities.

Isolation of Two Triterpene Saponins from Gypsophila capillaris (Forssk.)

Abstract Two novel natural products 1 and 2, both C-28 glycosides of triterpenoids, have been isolated from Gypsophila capillaris (Forssk.). Their structures were elucidated by 1D and 2D NMR techniques and other spectroscopic evidences.

Villosagenin I and II Two Novel Pentacyclic 28-Nortriterpenes from Silene villosa (Forssk.)

Abstract Two novel 28-nortriterpenoids, villosagenin I (1) and II (2), have been isolated from Silene villosa (Forssk.) (Caryophyllaceae) after hydrolysis of the saponin fraction. Their structures were elucidated by spectroscopic methods and all 1H and 13C signals assigned by 1D and 2D NMR techniques.

A note on a micro and a semimicro method for the assay of ephedrine.

Two colorimetric methods for the assay of ephedrine are proposed. One is a semi‐micro method in which the intensity of red colour produced by the oxidation of ephedrine with hydrogen peroxide is measured. The other is a micro method in which measurement is made of the intensity of the brown colour of the respective copper dithiocarbamate, produced by interaction of ephedrine, carbon disulphide and ammoniacal copper sulphate, the limit of sensitivity being 100 μg. Both methods gave reproducible results when used to assay ephedrine in pharmaceutical preparations. Results were compared with those from the Egyptian pharmacopoeial method.

A Simple Photometric Assay of Papaverine in Dosage Forms

Abstract The method depends upon reducing papaverine with Zn/HC1 to a secondary base which could interact with fluoranil giving a charge-transfer complex with two prominent absorption maxima (350 and 530 nm). The method suits control analysis of papaverine-containing pharmaceuticals. The measured color is relatively stable, obeyed Beers law (20-200 μg/ml° and showed % average recovery of 98.88 + 0.9.