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At least 955 records · Page 53Linked to original sources
PubMed1993

Photodegradation products of levofloxacin in aqueous solution.

The photodegradation of levofloxacin (DR-3355, CAS 100986-85-4), the S-(-)-isomer of ofloxacin, was investigated. Levofloxacin in aqueous solution was exposed to near ultraviolet light (peak wavelength 352 nm) for 16 h at room temperature. Nine degradation products (P-2-P-10) were isolated from the reaction mixture by preparative high performance liquid chromatography. The structures of these compounds were deduced from their NMR, MS, UV and IR spectra and optical rotations. The elucidated structures showed that all of these degradation products were analogues altered at the N-methylpiperazine moiety of levofloxacin.

Chromatography, High Pressure Liquid↗
PubMed1993

Extraction, purification and evaluation of structures and physico-chemical properties of glycosaminoglycans.

Heparin was extracted and purified from beef intestinal mucosa. The two components, fast moving heparin and slow moving heparin were purified by selective precipitation as barium salts. Heparan sulfate was extracted and purified from beef spleen. Dermatan sulfate was purified from beef intestinal mucosa and chondroitin sulfate from bovine trachea. The purity of the purified glycosaminoglycans was evaluated by agarose-gel and cellulose polyacetate electrophoresis and by specific optical rotation. The relative molecular masses of glycosaminoglycans were estimated by high performance-size exclusion chromatography and the sulfate to carboxyl ratio by titrimetric analysis. The disaccharide pattern of heparin, fast moving and slow moving heparins and heparan sulfate were determined by specific enzymatic cleavage using heparinase I, II and III; the disaccharide composition of dermatan sulfate and chondroitin sulfate was evaluated by cleavage by chondroitinase ABC. The disaccharides obtained by enzymatic cleavage were qualitatively and quantitatively analysed by strong anion exchange-high performance liquid chromatography. The sulfate to carboxyl ratios of glycosaminoglycans were also determined by this technique and compared with the values obtained by titrimetric analysis.

Animals↗
PubMed1977

Studies on trypsin inhibitors. Part VII. Synthesis of protected peptides related to sequences 1 - 14 and 36 - 52 of porcine pancreatic secretory trypsin inhibitor II (Kazal).

The synthesis, by fragment condensation, of protected peptides related to the N-terminal (positions 1-14) and C-terminal (positions 36-52) portions of the amino acid sequence of porcine pancreatic secretory trypsin inhibitor II (Kazal type) is described. The alpha-carboxyl function of the lysyl residue in position 14 was used as the free acid, or protected by the tert-butyloxycarbonylhydrazide. Two different synthetic pathways were used in the preparation of the 36-52 sequence of the inhibitor. The identity and purity of the synthesized peptide derivatives were established by amino acid analysis of acid hydrolysates, optical rotation and this layer chromatography in two solvent sytems. The final products were also evaluated, after partial deprotection with anhydrous hydrogen fluoride or aqueous 90% trifluoroacetic acid, by paper electrophoresis at different pH values and enzymic digestion with papain and aminopeptidase M followed by quantitative amino acid analysis.

Amino Acid Sequence↗
PubMed1977

Chemical structure of the galactomannan from the cell wall of Aspergillus niger.

The galactomannan of surface grown Aspergillus niger has been isolated by alkaline extraction of hyphal walls and characterized structurally. Its elution profile, from a column of Bio-Gel P-150, reveals a broad range of molecular sizes grouped into two fractions. Gas chromatographic and colorimetric analyses indicate that each fraction is composed of approximately equimolar quantities of galactose and mannose plus 12 to 14% glucose. Both have similar low optical rotations and contain acid labile galactose. Methylation, Smith degradation, acetolysis, reactivity with concanavalin A and beta-D-galactofuranosidase, plus digestionof galactose with D-galactose oxidase, were techniques employed to determine the polysaccharide's covalent structure. Results of these studies indicate that it is composed of a series of chains, 5 to 9 hexose units in length, connected by alpha1 leads to 6 bonds between mannopyranosyl moieties. The external portion of each chain consists of a galactose tri- or tetrasaccharide of the general structure Galf beta1 leads to 4 Galp(1-2) 1 leads to 4 Galp1 leads to. This segment is connected via a (1 leads to 2) linkage to the internal portion which is a di- to pentasaccharide of mannopyranosyl units joined in alpha1 leads to 2 glycoside linkage. Combination mild acid hydrolysis and methylation experiments indicate galactofuranosyl terminal units are attached only to galactose. The organization of glucose into the overall structure of the polymer has not been determined. Structural relationships of this polysaccharide to both fungal and yeast galactomannans are discussed.

Aspergillus↗
PubMed1977

Identification of D-threo-alpha-methylisocitrate as stereochemically specific substrate for bovine heart aconitase and inhibitor of TPN-linked isocitrate dehydrogenase.

DL-threo-alpha-Methylisocitrate (3-hydroxy-1,2,3-butanetricarboxylate) is a substrate for bovine heart aconitase and an inhibitor of TPN-linked isocitrate dehydrogenase from liver and heart. The isomer of alpha-methylisocitrate formed from alpha-methyl-cis-aconitate (cis-2-butane-1,2,3-tricarboxylate) by aconitase inhibits TPN-linked isocitrate dehydrogenase and has been identified as D-threo-alpha-methylisocitrate (2S,3R)-3-hydroxy-1,2,3-butanetricarboxylate) by optical rotation and circular dichroism studies. Mitochondrial bovine heart aconitase catalyzes a reversible reaction between D-threo-alpha-methylisocitrate (Km, 0.2 mM) and alpha-methyl-cis-aconitate (Km, 0.05 mM) at pH 7.4. However, formation of methylcitrate (2-hydroxy-1,2,3-butanetricarboxylate) from these substrates or utilization of synthetic methylcitrate for formation of these products could not be demonstrated with bovine heart aconitase. DL-threo-alpha-Methylisocitrate is also a substrate for aconitase from rat liver cytosol (Km, 0.1 mM); Vmax with citrate is approximately 1.4 times that with DL-threo-alpha-methylisocitrate. The ratio of activities for these substrates observed with the bovine heart enzyme is about 5. Formation of alpha-methyl-cis-aconitate from synthetic methylcitrate could not be detected spectrophotometrically with the liver aconitase; if it occurs with either the liver or the heart enzyme, the rate would be less than 0.1% that obtained with DL-threo-alpha-methylisocitrate. A new synthesis of methylcitric acid in good yields from diethyl alpha-methyl-beta-ketoglutarate (diethyl 2-methyl-3-oxoglutarate) and cyanide has been described. NMR spectroscopy indicates that this synthetic methylcitric acid contains the two racemic pairs of diastereoisomers.

Aconitate Hydratase↗
PubMed1978

Polypeptide antibiotic 26a from Bacillus subtilis. III. Physicochemical and biological in vitro properties.

Antibiotic 26a, a weakly basic (pK1 3.85 and pK2 7.1) polypeptide compound, has been recovered from the fermentation fluids of bacillus subtilis cultures as hydrochloride salt easily soluble in water and dimethylsulphoxide, sparingly soluble in lower alcohols and insoluble in several organic solvents. At low concentrations 26a was effective against gram-positive bacteria, mainly micrococci and corynebacteria, moderately active against mycobacteria, and inactive against gram-negative bacteria, yeasts and moulds even at 300 microgram/ml concentration. From the viewpoint of elemental analysis, electrometric titration, optical rotation, UV, IR and NMR spectra, amino acid composition, molecular weight and biological observations, 26a can be considered as an antibiotic, if not identical, then closely related to bacitracin family polypeptides.

Amino Acids↗
PubMed1995

[Cholecalciferol reference standard (Control 941) of the National Institute of Health Sciences].

The raw material for cholecalciferol was tested for preparation of the "Cholecalciferol Reference Standard (Control 941)". Analytical data obtained were as follows: melting point, 88.5 degrees C; UV and infrared spectra, the same as those for JP Cholecalciferol Reference Standard (Control 923), respectively; specific absorbance at 265 nm E1%1cm = 471; optical rotation, [alpha]20D = +107.3 degrees; thin-layer chromatography and high-performance liquid chromatography (HPLC), no impurities were detected, respectively; assay, 101.3% by HPLC. Based on the above results, the candidate raw material was authorized as the Japanese Pharmacopoeia Reference Standard (Control 941).

Chemical Phenomena↗
PubMed1995

[Prednisolone acetate reference standard (Control 941) of the National Institute of Health Sciences].

The raw material for prednisolone acetate was tested for preparation of the "Prednisolone Acetate Reference Standard (Control 941)". Analytical data obtained were as follows: melting point, 237.5 degrees C (decomposition); UV and infrared spectra, the same as those for JP Prednisolone Acetate Reference Standard (Control 903), respectively; specific absorbance at lambda max E1%1cm = 379; optical rotation, [alpha]20D = +115.2 degrees; thin-layer chromatography and high-performance liquid chromatography (HPLC), no impurities were detected, respectively; assay, 100.8% by HPLC. Based on the above results, the candidate material was authorized as the Japanese Pharmacopoeia Reference Standard (Control 941).

Chemical Phenomena↗
PubMed1995

[Betamethasone valerate reference standard (Control 941) of the National Institute of Health Sciences].

The raw material for betamethasone valerate was tested for preparation of the "Betamethasone Valerate Reference Standard (Control 941)". Analytical data obtained were as follows: melting point, 194.3 degrees C (decomposition); UV and infrared spectra, the same as those for JP Betamethasone Valerate Reference Standard (Control 844); optical rotation, [alpha]20D = +79.4 degrees; thin-layer chromatography and high-performance liquid chromatography (HPLC), no impurities were detected; assay, 100.0% by HPLC. Based on the above results, the candidate material was authorized as the JP Betamethasone Valerate Reference Standard (Control 941).

Betamethasone Valerate↗
PubMed1994

[The Dexamethasone Reference Standard (Control 931) of the National Institute of Health Sciences].

Raw dexamethasone material was tested for preparation of the "Dexamethasone Reference Standard (Control 931)". Analytical data obtained were as follows: melting point, 245.1 degrees C (decomposition); infrared spectrum, the same as that of the JP Dexamethasone Reference Standard; optical rotation, -alpha-20D = + 76.75 degrees; thin-layer chromatography, two impurities were detected; high-performance liquid chromatography (HPLC), one impurity was detected; loss on drying, 0.14%; assay result, 99.4% by HPLC. Based on the above findings, the raw material was authorized as the JP Dexamethasone Reference Standard (Control 931).

Chemical Phenomena↗
PubMed1994

[The Progesterone Reference Standard (Control 931) of the National Institute of Health Sciences].

Raw progesterone material was tested for preparation of the "Progesterone Reference Standard (Control 931)". Analytical data obtained were as follows: melting point, 131.6 degrees C; infrared spectrum, the same as that of the JP Progesterone Reference Standard; optical rotation, [alpha]D20 = +181.1 degrees; thin-layer chromatography, no impurity was detected; high-performance liquid chromatography (HPLC), trace amounts of two impurities were detected; loss on drying, 0.23%; assay results, 99.4% by UV spectrophotometry in the JP XII and 100.5% by HPLC. Based on the above findings, the raw material was authorized as the JP Progesterone Reference Standard (Control 931).

Chemical Phenomena↗
PubMed1994

[Estradiol Reference Standard (Control 931) of National Institute of Health Sciences].

The raw material for estradiol was examined for preparation of the "National Institute of Health Sciences (NIHS) Estradiol Reference Standard (Control 931)". Analytical data obtained were as follows: melting point, 179.0 degrees C; infrared spectrum, the same as that of the present NIHS Estradiol Reference Standard; optical rotation, -alpha-20D = +80.4 degrees; thin-layer chromatography, no impurity was detected; high-performance liquid chromatography (HPLC), a trace amount of two impurities were detected; loss on drying, 0.24%; assay, 100.4% by UV spectrophotometry and 101.2% by HPLC. Based on the above results, the raw material was authorized as the NIHS Estradiol Reference Standard (Control 931).

Chemical Phenomena↗
PubMed1994

[The Ascorbic Acid Reference Standard (Control 931) of the National Institute of Health Sciences].

Raw ascorbic acid material was tested for preparation of the "Ascorbic Acid Reference Standard (Control 931)". Analytical data obtained were as follows: infrared spectrum, the same as that of the JP Ascorbic Acid Reference Standard; optical rotation -alpha-20D, + 21.4 degrees; melting point, 190.3 degrees C (decomposition); loss on drying, 0.02%; assay result, 100.1% by iodometry. Based on the above findings, the raw material was authorized as the JP Ascorbic Acid Reference Standard (Control 931).

Ascorbic Acid↗
PubMed1994

[The Testosterone Propionate Reference Standard (Control 881) of the National Institute of Health Sciences].

Raw testosterone propionate material was tested for preparation of the "Testosterone Propionate Reference Standard (Control 881)". Analytical data obtained were as follows: loss on drying, 0.1%; melting point, 120.6 degrees C; optical rotation [alpha]20D = + 85.4 degrees; ultraviolet spectrum, lambdamax = 241 nm and specific absorbance E 1cm1% (241 nm) = 483; infrared spectrum, the same as that of the NIHS Testosterone Propionate Reference Standard; thin-layer chromatography, no impurities were detected; high-performance liquid chromatography (HPLC), one impurity was detected; assay result, 100.6% by UV spectrophotometry. Based on the above findings, the raw material was authorized as the Testosterone Propionate Reference Standard (Control 881) of the National Institute of Health Sciences.

Chemical Phenomena↗
PubMedDate not supplied

Alkaloids of thalictrum. XX. Isolation, identification and structural elucidation of the alkaloids of the root of Thalictrum longistylum.

A study of the alkaloids of the roots of Thalictrum longistylum DC. resulted in the isolation of 12 alkaloids plus an artifact, 8-trichloromethyldihydroberberine. The 12 alkaloids were berberine, columbamine, jatrorrhizine, magnoflorine, methothalistyline, N-desmethylthalistyline, oxyberberine, palmatine, thalibrine, thalifendine, thaliglucinone, and thalistyline. Of these alkaloids, methothalistyline, N-desmethylthalistyline, and thalistyline are new compounds and with thaliglucinone possess hypotensive activity in dogs and rabbits. Methothalistyline, N-demethylthalistyline, thalistyline, and thalibrine were found to be active against Staphylococcus aureus and Mycobacterium smegmatis with with thalistyline being most active (50 microgram/ml).

Alkaloids↗
PubMedDate not supplied

Structure elucidation of norlaureline and puterine, new noraporphine alkaloids from Guatteria elata.

The structures of norlaureline (1) and puterine (4), new noraporphine alkaloids isolated from Guatteria elata (Annonaceae), were established by interpretation of the optical rotation, uv, ir, pmr, and mass spectral data of their N-acetyl derivatives. Proposed structures were confirmed by transformation of 1 and 4 to laureline (3) and pukateine methyl ether (6), respectively.

Aporphines↗
PubMed1997

4-aryl-5-oxo-1,2,3,4,5,6,7,8-octahydroquinazoline-2-thione derivatives: synthesis, enantiomeric separation and in vitro screening as calcium antagonists.

Fourteen new 4-aryl-5-oxo-1,2,3,4,5,6,7,8-octahydroquinazoline-2-thione derivatives were synthesized and screened in vitro for their calcium antagonistic activities. The compounds were prepared by reacting 1,3-cyclo-hexanedione with appropriate aromatic aldehydes and thiourea under modified Biginelli reaction conditions. The structures of the compounds were proved by IR, 1H-NMR, mass spectroscopy and elemental analysis. The compounds synthesized exerted calcium antagonistic action on smooth musculature by inhibiting BaCl2-induced contractions of isolated rat ileum. It was found that compound 12l having 3-methoxyphenyl group at the 4th position was the most potent compound in this series (pEC50: 4.00 +/- 0.20). Rasemic compound 12l was resolved into its enantiomers by high performance liquid chromatography (HPLC) using a commercially available cellulose tris(p-methylbenzoate) chiral stationary phase, known as Chiralcel OJ. The enantiomeric ratio was validated and peak identification for each enantiomer was established according to their optical rotation sign.

Animals↗
PubMed1997

[Epinephrine Bitartrate Reference Standard (Control 951) of National Institute of Health Sciences].

The raw material for epinephrine bitartrate was tested for preparation of the "Epinephrine Bitartrate Reference Standard (Control 951)" of National Institute of Health Sciences. Analytical data obtained were as follows: melting point, 148.6 degrees C (decomposition); UV spectrum, lambda max = 279 nm; IR spectrum, the same as that of JP Epinephrine Bitartrate Reference Standard (Control 792); optical rotation, [alpha]20D = -52.8 degrees; thin-layer chromatography, one impurity was detected; high-performance liquid chromatography, no impurity was detected; loss on drying, 0.01%; assay, 99.6% by potentiometric titration, 100.3% by spectrophotometry. Based on the above results, the raw material was authorized as the Epinephrine Bitartrate Reference Standard (Control 951) of National Institute of Health Sciences (Japanese Pharmacopoeia).

Epinephrine↗