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A Saeed

Publications and source records attributed to A Saeed.

52 records · Page 3Linked to original sources
PubMed1984

Cis isomer of centchroman--a selective ligand for the microsomal antiestrogen binding site.

Several compounds structurally related to the triarylethylene antiestrogens, but possessing weak estrogen receptor affinities, were assessed for their ability to interact with the microsomal antiestrogen binding site. While all the compounds tested did interact with this site their relative affinities were somewhat lower than that of tamoxifen. One of these, viz., the cis isomer of centchroman, has however emerged as a selective ligand for the antiestrogen binding site since its estrogen receptor affinity is nearly 50,000 times lower on a relative scale.

Animals↗
PubMed1980

Hen's egg yolk cholinesterase. Purification, characterization and comparison with hen's liver and blood plasma cholinesterase.

The cholinesterase (acylcholine acylkhydrolase, EC 3.1.1.8) of chicken egg yolk was partly purified and characterized. It was compared to homologous enzymes of liver and blood plasma of laying hens. During gel filtration, yolk and liver cholinesterase were resolved into two fractions. Blood plasma cholinesterase showed one form only, identical with yolk and liver cholinesterase 1 *** (EC 3.1.1.8). This form has an Mr of 440 000 and may be a tetramer of a cholinesterase form present in yolk and liver (Mr 104 000). Substrate specificity, pH optima, Km values, the influence of effectors (ammonium derivatives, choline, eserine, fluoride), gel filtration, gel electrophoresis, isoelectric focusing and affinity chromatography, all point to a very close similarity, if not identity, of the corresponding forms.

Animals↗
PubMedDate not supplied

Synthesis of 6-O-methyl ether of Scorzocreticin and Scorzocreticoside I, metabolites from Sorzonera cretica.

6-O-methyl ether of racemic scorzocreticin (1a) and its 8-O-beta-D-glucoside, scorzocreticoside I (1b), isolated from Greek endemic species Scorzonera cretica have been synthesized. 6,8-Dimethoxy-3-(4-methoxyphenyl)isocoumarin (3) was obtained by reaction of 3,5-dimethoxyhomophthalic acid (2) with 4-methoxy-benzoyl chloride at elevated temperature. Hydrolysis of isocoumarin (3) to keto acid (4) followed reduction and spontaneous cyclodehydration to afford ( +/- )-6,8-dimethoxy-3-(4-methoxyphenyl)-3,4-dihydroisocoumarin (5) which was regioselectively demethylated to ( +/- )-6-O-methylscorzocreticin (6). Glycosylation of the latter using 2,3,4,6-tetra-O-acetyl-alpha-D-glucopyranosyl bromide in the presence of silver carbonate in quinoline under Koenigs-Knorr conditions afforded 6-methoxy-8-O-glucoside tetraacetate (7) as a 1:1 diastereomeric mixture. Finally, deacetylation of (7) using sodium methoxide afforded the diastereomeric mixture of R and S 6-O-methylscorzocreticin 8-O-glucosides (8). The 6-O-methyl ether of natural scorzocreticoside I (1b) was separated and identified on the basis of sign of optical rotation.

Asteraceae↗