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Asfaw N, Storesund HJ, Skattebøl L, Aasen AJ. Coexistence of chrysanthenone, filifolone and (Z)-isogeranic acid in hydrodistillates. Artefacts! Phytochemistry 2001; 58:489-492. [PMID: 11557082 DOI: 10.1016/s0031-9422(01)00254-0] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
Hydrodistilled oil from leaves of the Ethiopian plant Laggera tomentosa has been shown to contain (-)-chrysanthenone (5%), (-)/(+)-filifolone (92:8; 8%) and (Z)-isogeranic acid (8%)-all likely to be artefacts. The main constituent of the oil, (+)-chrysanthenone (53%), is believed to be the precursor undergoing thermal and solvolytic reactions during the hydrodistillation process.
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Affiliation(s)
- N Asfaw
- School of Pharmacy, University of Oslo, PO Box 1068, Blindern, N-0316 Oslo, Norway
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2
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Abstract
The antibacterial activity of metal ions, metal chelates, and molecules with chelating ability for polyvalent cations have been evaluated. The chelator N, N'-ethylenebis[2-(2-hydroxyphenyl)-glycine] (EHPG) exerted moderate-to-good activity against isolates of pathogenic bacteria and fungi. Other chelating agents such as ethylenediamine-tetraacetic acid (EDTA) and diethylene-triamine-pentaacetic acid (DTPA) revealed weak-to-moderate activity. Metal chelation of ligands reduced the activity of EDTA and DTPA.
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Affiliation(s)
- T Bergan
- Institute of Microbiology, University of Oslo and Rikshospitalet (National Hospital), Oslo, Norway
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Abstract
BACKGROUND AND METHODS The antibacterial activity of originally devised and synthesized organobismuth compounds was tested against fresh clinical isolates of Helicobacter pylori and compared with clinically well-established inorganic bismuth salts currently used in triple antibacterial treatment to eradicate H. pylori. The test conditions in vitro were standard for determination of minimum inhibitory concentrations (MICs). RESULTS Organic compounds with covalently bound bismuth showed stronger and more consistent antibacterial activity than inorganic bismuth salts. Whereas the most active among the standard therapeutic inorganic compounds showed MICs against the test organisms of 4-8 mg/l (bismuth salicylate) and 0.5-64 mg/l, the most active neosynthesized organic substance, tris(2.6-dimethylphenyl)-bismuthine, consistently showed an MIC of 4 mg/l against all bacterial strains. CONCLUSIONS The new line of organobismuth compounds might offer a therapeutic potential against the bacteria causing peptic ulcer disease.
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Affiliation(s)
- A Dahlgren
- Dept. of Medicinal Chemistry, School of Pharmacy, University of Oslo, Norway
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5
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Marino F, Cosentino M, De Ponti F, Giaroni C, Somaini L, Bombelli R, Ferrari M, Aasen AJ, Lecchini S, Frigo G. Muscarinic modulation of endogenous noradrenaline release from adrenergic terminals in the guinea-pig colon. J Auton Pharmacol 1997; 17:365-72. [PMID: 9610431 DOI: 10.1046/j.1365-2680.1997.00057.x] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
1 The present study examined the role of muscarinic receptors in the modulation of noradrenaline (NA) release in the guinea-pig isolated distal colon. The spontaneous endogenous NA overflow assayed by HPLC-ED was taken as an index of NA release from enteric noradrenergic nerve terminals. 2 Physostigmine (10 microM) significantly enhanced spontaneous endogenous NA overflow. Hyoscine (muscarinic antagonist), (R)-(-)-trihexyphenidyl and telenzepine (M1-selective antagonists), and 11[[2-[(diethylamino)methyl]-1-piperydil]acetyl]-5,11 -dihydro-6H-pyrido[2,3-b][1,4]benzodiazepine-6-one (AF-DX 116, M2-selective antagonist) inhibited NA overflow in a concentration dependent manner, with the following EC50 values: 131.74 (18.19-953.96), 101.62 (58.83-175.60), 150 (60-330), 30 (5-170) nM, respectively. 4-diphenylacetoxy-N-methylpiperidine methiodide (4-DAMP, M1- and M3-selective antagonist) had no significant effect up to 100 microM. 3 The muscarinic agonist oxotremorine inhibited NA overflow in a concentration dependent manner, with an EC50 value of 0.67 (0.30-1.51) microM. The response to oxotremorine was inhibited by muscarinic antagonists with the following order of potency: hyoscine = (R)-(-)-trihexyphenidyl = telenzepine > 4-DAMP >> AF-DX 116. 4 In the presence of 3 microM tetrodotoxin (TTX), the effect of oxotremorine and 4-DAMP was unchanged, while hyoscine, (R)-(-)-trihexyphenidyl, telenzepine and AF-DX 116, instead of inhibiting, significantly enhanced NA overflow. 5 The present results indicate that, in the guinea-pig colon, endogenous acetylcholine sustains spontaneous NA release by activating muscarinic receptors possibly located on interneurones. In addition, inhibitory muscarinic receptors may exist on adrenergic terminals.
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Affiliation(s)
- F Marino
- Department of Internal Medicine and Therapeutics, II Faculty of Medicine, University of Pavia, Italy
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6
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Bugge A, Aasmundstad T, Aasen AJ, Christophersen AS, Morgenlie S, Mørland J. Synthesis of ethylmorphine-6-glucuronide: a metabolite of ethylmorphine in man. Acta Chem Scand (Cph) 1995; 49:380-4. [PMID: 7766464 DOI: 10.3891/acta.chem.scand.49-0380] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Affiliation(s)
- A Bugge
- National Institute of Forensic Toxicology, Oslo, Norway
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7
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Onali P, Aasen AJ, Olianas MC. Antagonism by (R)- and (S)-trihexyphenidyl of muscarinic stimulation of adenylyl cyclase in rat olfactory bulb and inhibition in striatum and heart. Br J Pharmacol 1994; 113:775-80. [PMID: 7858866 PMCID: PMC1510423 DOI: 10.1111/j.1476-5381.1994.tb17060.x] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023] Open
Abstract
1. Activation of muscarinic receptors in rat olfactory bulb stimulates adenylyl cyclase activity. This response was competitively antagonized by the (R)- and (S)-enantiomers of trihexyphenidyl with pA2 values of 8.84 and 6.09, respectively. 2. Similarly, in rat striatal homogenates, muscarinic inhibition of adenylyl cyclase activity was antagonized by the (R)- and (S)-enantiomers with pA2 values of 8.75 and 6.12, respectively. 3. In contrast, in rat myocardium the muscarinic inhibition of the adenosine 3':5'-cyclic monophosphate (cyclic AMP) formation was more weakly antagonized by trihexyphenidyl, with a particularly marked loss (15 fold) in activity of the (R)-enantiomer. The (R)- and (S)-enantiomers had pA2 values of 7.64 and 5.72, respectively. 4. Each muscarinic response was completely antagonized by increasing concentrations of (R)-trihexyphenidyl with a Hill coefficient not significantly different from unity. 5. The present study shows that the muscarinic receptors coupled to stimulation of adenylyl cyclase in the olfactory bulb display high stereoselectivity for the enantiomers of trihexyphenidyl. The affinities of these receptors for the antagonists are similar to those shown by the striatal receptors. This finding supports the hypothesis that both the muscarinic stimulation of adenylyl cyclase in the olfactory bulb and the muscarinic inhibition of the enzyme in striatum are mediated by activation of a receptor subtype pharmacologically equivalent to the m4 gene product. On the other hand, the weaker affinities and the lower stereoselectivity for the trihexyphenidyl enantiomers exhibited by the muscarinic inhibition of adenylyl cyclase in the heart are consistent with the involvement of M2 receptors in this response.
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Affiliation(s)
- P Onali
- Department of Neurosciences, University of Caliari, Italy
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8
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Sjö P, Aasen AJ. Anticholinergic agents. 4. Stereocontrolled synthesis of fluorinated acetylcholine antagonists; syntheses of the two 1-cyclohexyl-1-(4-fluorophenyl)-3-piperidyl-1-propanols and their methiodides. Acta Chem Scand (Cph) 1993; 47:1019-24. [PMID: 8240907 DOI: 10.3891/acta.chem.scand.47-1019] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
Four new putative muscarinic antagonists, (R)-(-)- and (S)-(+)-1-cyclohexyl-1-(4-fluorophenyl)-3-piperidyl-1-propanol and their methiodides, have been synthesised. Absolute configurations have been assigned on the basis of the anticipated chirality of the products of the Sharpless asymmetric epoxidation reaction.
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Affiliation(s)
- P Sjö
- Department of Pharmacy, University of Oslo, Norway
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9
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Feifel R, Rodrigues de Miranda JF, Strohmann C, Tacke R, Aasen AJ, Mutschler E, Lambrecht G. Selective labelling of muscarinic M1 receptors in calf superior cervical ganglia by [3H](+/-)-telenzepine. Eur J Pharmacol 1991; 195:115-23. [PMID: 2065706 DOI: 10.1016/0014-2999(91)90388-7] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
A method was developed to determine the affinities of antimuscarinic drugs at M1 receptors. [3H](+/-)-Telenzepine served as radioligand in crude preparations of calf superior cervical ganglia and showed high affinity for a single receptor population, consisting of M1 receptors (KD = 1.12 nM). Kinetic experiments showed monophasic association (k1 = 0.017 min-1 nM-1) and dissociation (k-1 = 0.017 min-1) kinetics, the half-life of dissociation being 41 min at 37 degrees C. The kinetic KD value amounted to 1.00 nM. M1 affinities for pirenzepine, methoctramine, hexahydro-sila-difenidol and p-fluoro-hexahydro-sila-difenidol determined in competition experiments were similar to those found in functional studies with M1 receptors in rabbit isolated vas deferens. The binding assay was used to determine the affinities of the (R) and (S) enantiomers of tertiary (trihexyphenidyl, hexahydro-difenidol, hexbutinol, p-fluoro-hexbutinol) and quaternary muscarinic antagonists (trihexyphenidyl methiodide, hexbutinol methiodide). Comparison of results obtained with the rabbit vas deferens suggested that the ionic environment may influence the affinities.
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Affiliation(s)
- R Feifel
- Department of Pharmacology, University of Frankfurt, Main, F.R.G
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10
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Sjö P, Groth P, Aasen AJ. Anticholinergic agents. 2. Absolute configurations of 2-methyl-1,1-diphenyl-3-(1-piperidyl)-1-propanol and 2-methyl-1,1-diphenyl-3-(1-pyrrolidyl)-1-propanol. Crystal structures of the corresponding mandelates. Acta Chem Scand (Cph) 1990; 44:957-62. [PMID: 2291863 DOI: 10.3891/acta.chem.scand.44-0957] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Racemic 2-methyl-1,1-diphenyl-3-(1-piperidyl)-1-propanol (4) and 2-methyl-1,1-diphenyl-3-(1-pyrrolidyl)-1-propanol (5) have been synthesized and optically resolved employing (R)- and (S)-mandelic acid, respectively, as resolving agents. The absolute configurations of the enantiomers of 4 and 5 have been established as (-)-(R) and (+)-(S) by crystal structure analyses of (-)-(R)-2-methyl-1,1-diphenyl-3-(1-piperidinio)-1-propanol (+)-(S)-mandelate and (+)-(S)-2-methyl-1,1-diphenyl-3-(1-pyrrolidinio)-1-propanol (-)-(R)-mandelate. The corresponding methiodides have been prepared.
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Affiliation(s)
- P Sjö
- Department of Pharmacy, University of Oslo, Norway
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11
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Ruud-Christensen M, Aasen AJ, Rasmussen KE, Salvesen B. High-performance liquid chromatographic determination of (R)-and (S)-proxyphylline in human plasma. J Chromatogr 1989; 491:355-66. [PMID: 2808621 DOI: 10.1016/s0378-4347(00)82853-4] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
A reversed-phase high-performance liquid chromatographic assay has been developed for determination of (R)-(--)-and (S)-(+)-proxyphylline in human plasma. The procedure is based on liquid-solid extraction of proxyphylline from plasma followed by derivatization of extracted proxyphylline with (--)-camphanoyl chloride. The ratio between the enantiomers is calculated from the peak areas of the corresponding diastereoisomeric proxyphylline camphanates after injection into the liquid chromatograph. The recovery of proxyphylline from plasma was 88% (coefficient of variation = 4%) and proxyphylline was detectable from a plasma concentration of 0.2 micrograms/ml. Three different plasma extraction procedures for proxyphylline using Extrelut, Bond Elut, and Chem Elut columns have been developed and compared, and the rate of derivatization of the proxyphylline enantiomers with camphanoyl chloride has been studied.
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12
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Abstract
The (+)- and (-)-enantiomers of benproperinium dihydrogen phosphate, an antitussive drug, have been assigned the R- and S-configurations, respectively, by syntheses of both enantiomers using (S)-2-hydroxypropanoic acid (L-lactic acid) as chiral synthon. The key intermediate, (S)-1-methyl-2-[2-(phenylmethyl)phenoxy]ethyl p-toluenesulfonate, was subjected to an SN2-type reaction with piperidine furnishing (+)-(R)-benproperinium dihydrogen phosphate. (-)-(S)-Benproperinium dihydrogen phosphate was obtained by submitting the same tosylate to two consecutive SN2-type reactions with Br- and piperidine, respectively, acting as nucleophiles.
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Lambrecht G, Feifel R, Moser U, Aasen AJ, Waelbroeck M, Christophe J, Mutschler E. Stereoselectivity of the enantiomers of trihexyphenidyl and its methiodide at muscarinic receptor subtypes. Eur J Pharmacol 1988; 155:167-70. [PMID: 3243330 DOI: 10.1016/0014-2999(88)90417-7] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
High stereoselectivity was observed for the enantiomers of trihexyphenidyl and trihexyphenidyl methiodide at muscarinic M1-receptors in field-stimulated rabbit vas deferens and at M2 alpha- and M2 beta-receptors in guinea-pig atrium and ileum, respectively. Considerably higher affinities (up to 1700-fold) were found for the (R)-(-)-enantiomers. The stereochemical demands made by the muscarinic receptor subtypes were most stringent at the M1-receptors. The (R)-(-)-enantiomers were found to be potent M1-selective antagonists (pA2 = 10.1/10.6). They showed a 91- and 45-fold selectivity for M1- over M2 alpha-receptors, respectively.
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Affiliation(s)
- G Lambrecht
- Department of Pharmacology, University of Frankfurt, Federal Republic of Germany
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14
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Nguyen TT, Kringstad R, Aasen AJ, Rasmussen KE. Identification and analysis of a degradation product of the glucocorticoid desonide in ointment. Acta Chem Scand B 1988; 42:403-7. [PMID: 3195294 DOI: 10.3891/acta.chem.scand.42b-0403] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
The major degradation product of desonide in a pharmaceutical ointment formulation has been shown to be identical with the C-17-carboxylic acid obtained on oxidative cleavage of the alpha-ketol group of desonide with alkaline hydrogen peroxide. The pKa value of this acid has been estimated from chromatographic data.
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Affiliation(s)
- T T Nguyen
- Pharmaceutical Quality Assurance, Apothekernes Laboratorium A.S., Oslo, Norway
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15
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Abstract
The (R)-(+)- and (S)-(-)-enantiomers of the anticholinergic compound, oxyphencyclimine, were synthesized from (R)-(-)- and (S)-(+)-2-cyclohexyl-2-hydroxy-2-phenylethanoic acid, respectively. The potencies of the enantiomers were compared using a cholinergic receptor binding assay. The (R)-(+)-enantiomer inhibited binding 29 times more potently than the (S)-(-)-enantiomer.
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Affiliation(s)
- L Schjelderup
- Department of Chemistry, Agricultural University of Norway
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Schjelderup L, Harbitz O, Groth P, Aasen AJ. Syntheses of (S)-(+)-trihexyphenidyl hydrochloride and (S)-(+)-procyclidine hydrochloride, two anticholinergics, using (S)-(-)-3-cyclohexyl-3-hydroxy-3-phenylpropanoic acid as chiral synthon. Acta Chem Scand B 1987; 41:356-61. [PMID: 3673449 DOI: 10.3891/acta.chem.scand.41b-0356] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
The absolute configuration of the more active (-)-enantiomer of the anticholinergic trihexyphenidyl hydrochloride has been established as (R) by syntheses of (S)-(+)-procyclidine hydrochloride, whose absolute configuration has been established previously, and (S)-(+)-trihexyphenidyl hydrochloride from the same chiral building block, viz. (S)-(-)-cyclohexyl-3-hydroxy-3-phenylpropanoic acid. Both enantiomers of this chiral synthon were prepared by optical resolution of the corresponding racemate, employing (R)- and (S)-1-phenylethylamine, respectively, as resolving agents.
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Affiliation(s)
- L Schjelderup
- Department of Chemistry, Agricultural University of Norway, Oslo
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17
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Marnela KM, Hagen EA, Aasen AJ, Loennechen T, Sydnes LK, Timonen M, Lähdesmäki P. Mass spectrometric studies of some synaptosomal and synthetic peptides. Int J Neurosci 1984; 25:123-30. [PMID: 6526586 DOI: 10.3109/00207458408985594] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
Mass spectra were recorded using direct inlet and electron impact ionization from two synthetic peptides, N-acetyl-aspartyl-4-aminobutyric acid and gamma-glutamyl-taurine and a natural peptide, N-acetyl-aspartyl-glycyl-alanyl-aspartyl-serine, isolated from calf brain synaptosomes. The peptides were studied either underivatized or first acetylated with acetic acid anhydride and then permethylated with methyl iodide. The synthetic peptides were used to check the completeness of the derivatization reactions.
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Hagen EA, Loennechen T, Sydnes LK, Aasen AJ. Synthesis of Ac-Asp-Gly-Ser and Ac-Asp-Pro-Leu-Gly-NH2. Int J Pept Protein Res 1984; 23:642-649. [PMID: 6469462] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 05/21/2023]
Abstract
The syntheses of Ac-Asp-Gly-Ser and Ac-Asp-Pro-Leu-Gly-NH2 are described. The two peptides were prepared in solution by stepwise elongation using the DCC method with additives (HOSu or HOBt). The push-pull method was also used in the synthesis of Ac-Asp-Gly-Ser. A racemization test of the amino acids in this peptide has been performed.
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Abstract
The syntheses of the L,L- and D,D-stereoisomers of N-phenoxyacetyl-X-alanine in which X=His, Tyr, or Lys, are described. The antibacterial activity of some of the peptide derivatives and their synthetic intermediates have been examined. Some of the intermediates exhibited moderate activity against viridans streptococci, enterococci and Streptococcus agalactiae. None of the compounds were active against beta-lactamase producing bacteria or served as beta-lactamase inhibitors.
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Hagen EA, Bergan T, Aasen AJ. Synthesis of analogs of D-Ala-D-Ala as potential inhibitors of bacterial cell wall biosynthesis. Acta Chem Scand B 1984; 38:5-14. [PMID: 6375222 DOI: 10.3891/acta.chem.scand.38b-0005] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
The syntheses of the L,L- and D,D-stereoisomers of N- phenoxyacetyl -X-alanine in which X = Ser, Ala( beta Cl ) or Arg, are described. The antibacterial activity of these peptides and some of their synthetic intermediates has been examined. Four of the intermediates in which X = Ala( beta Cl ) and Arg(NO2), which possess C-terminal benzyl ester groups, were active against viridans streptococci and Streptococcus agalactiae. The D,D-enantiomers were more active than the corresponding L,L-isomers. None of the compounds were active against beta-lactamase producing bacteria or acted as beta-lactamase inhibitors.
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Selvig K, Ruud-Christensen M, Aasen AJ. Optical resolution, absolute configuration, and activity of the enantiomers of proxyphylline. J Med Chem 1983; 26:1514-8. [PMID: 6620311 DOI: 10.1021/jm00364a029] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
The enantiomers of proxyphylline have been separated via their corresponding camphanates. Synthesis of (+)-proxyphylline from theophylline and (S)-propylene oxide derived from (S)-lactic acid established the absolute configuration of the (+) and (-) isomer as S and R, respectively. The activity of the enantiomers as cyclic nucleotide phosphodiesterase inhibitors was tested in human lung tissue homogenate. No differences were found either between the two enantiomers or between the enantiomers and racemic proxyphylline.
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Størmer FC, Støren O, Hansen CE, Pedersen JI, Aasen AJ. Formation of (4R)- and (4S)-4-hydroxyochratoxin A and 10-hydroxyochratoxin A from Ochratoxin A by rabbit liver microsomes. Appl Environ Microbiol 1983; 45:1183-7. [PMID: 6859843 PMCID: PMC242436 DOI: 10.1128/aem.45.4.1183-1187.1983] [Citation(s) in RCA: 58] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023] Open
Abstract
Three metabolites were formed from ochratoxin A in the presence of rabbit liver microsomal fractions and NADPH. They were isolated by extraction, thin-layer chromatography, and high-pressure liquid chromatography. Two of them were identified as (4R)- and (4S)-4-hydroxyochratoxin A. It is suggested on the basis of mass and nuclear magnetic resonance spectroscopy that the third metabolite is 10-hydroxyochratoxin A. The formation of the metabolites was inhibited by carbon monoxide and metyrapone and was stimulated when microsomes from phenobarbital-treated animals were used. The results suggest that cytochrome P-450 catalyzes the formation of these metabolites.
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Størmer FC, Hansen CE, Pedersen JI, Hvistendahl G, Aasen AJ. Formation of (4R)- and (4S)-4-hydroxyochratoxin A from ochratoxin A by liver microsomes from various species. Appl Environ Microbiol 1981; 42:1051-6. [PMID: 7316512 PMCID: PMC244153 DOI: 10.1128/aem.42.6.1051-1056.1981] [Citation(s) in RCA: 57] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023] Open
Abstract
Two metabolic products were formed from ochratoxin A by human, pig, and rat liver microsomal fractions in the presence of reduced nicotinamide adenine dinucleotide phosphate. They were isolated from the incubation mixture in the presence of pig liver microsomes by extraction, thin-layer chromatography, and high-pressure liquid chromatography Their structures are suggested to be (4R)- and (4S)-4-hydroxyochratoxin A on the basis of mass and nuclear magnetic resonance spectroscopy. Km and the maximum velocity for the formation of the two metabolites by human, pig, and rat microsomes were determined. Their formation was inhibited by carbon monoxide and metyrapone. The results indicate that the microsomal hydroxylation system is a cytochrome P-450 and that different species are involved in the formation of the two epimeric forms of 4-hydroxyochratoxin A.
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Aasen AJ, Hlubucek JR, Enzell CR. Tobacco chemistry. 27. The structures of four stereoisomeric 8, 12x1-epoxylabd-14-en-13xl-ols isolated from Greek Nicotiana tabacum L. Acta Chem Scand B 1975; 29:589-92. [PMID: 1166724 DOI: 10.3891/acta.chem.scand.29b-0589] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
The structures of four stereoisomeric 8,12x1-expoxylabd-14-en-13x1-ols** obtained from Greek tobacco were determinedby spectroscopic means and by conversion to 12-norambreinolide. Plausible routes for the formation of the new labdanols and related tobacco constituents from a common precursor, abienol, are discussed.
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25
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Aasen AJ, Hlubucek JR, Enzell CR. Tobacco Chemistry.29. (7S)-10-Oxo-4xi-methyl-7-isopropyl-5E-undecen-4-olide, a New Thunbergan-type Nor-isoprenoid isolated from Greek Nicotiana tabacum L. Acta Chem Scand B 1975; 29:677-81. [PMID: 1189845 DOI: 10.3891/acta.chem.scand.29b-0677] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
The structure of a new C15-lactone, (7S)-10-oxo-4xi-methyl-7-isopropyl-5E-undecen-4-olide, isolated from Greek tobacco, has been determined mainly be 1H NMR, 13C NMR and high resolution MS, and its absolute configuration established by degradation to (2S)-5-oxo-2-isopropylhexanal. The carbon skeleton of the new compound indicated that it is derived from a thunbergane precursor and constitutes the first C15 nor-thunberganoid in tobacco.
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Aasen AJ, Hlubucek JR, Almqvist SO, Kimland B, Enzell CR. Tobacco chemistry. 20. Structures and syntheses of three new tobacco constituents of probable isoprenoid origin. Acta Chem Scand 1973; 27:2405-10. [PMID: 4778902 DOI: 10.3891/acta.chem.scand.27-2405] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
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Aasen AJ, Liaaen-Jensen S, Borch G, Andresen AF, Pearson WB, Meisalo V. Carotenoids of Flexibacteria. V. The Chirality of Zeaxanthin from Different Natural Sources. ACTA ACUST UNITED AC 1972. [DOI: 10.3891/acta.chem.scand.26-0404] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
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Aasen AJ, Hofstetter HH, Iyengar BTR, Holman RT. Identification and analysis of wax esters by mass spectrometry. Lipids 1971; 6:502-7. [DOI: 10.1007/bf02531236] [Citation(s) in RCA: 67] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/1970] [Indexed: 11/28/2022]
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Aasen AJ, Kimland B, Enzell CR. Tobacco Chemistry. 11. Total Synthesis of 5-Methoxy-6,7-dimethylbenzofuran, a New Tobacco Constituent. ACTA ACUST UNITED AC 1971. [DOI: 10.3891/acta.chem.scand.25-3537] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
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Abstract
The conformations of
3-oxopyrrolizidine derivatives are discussed on the basis of an analysis of the
nuclear magnetic resonance spectrum of 3,5-dioxopyrrolizidine and partial data
for methyl 2,3- dioxopyrrolizidine-1-carboxylate and methyl 2β-hydroxy-3-
oxopyrrolizidine-1a-carboxylate. In each compound, H 7β is located forward
into the fold of the rings and is subject to a shielding influence which is
thought to be due to the C 8-C 1 single bond.
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Aasen AJ, Lauer WM, Holman RT. Mass spectrometry of triglycerides. II. Specifically deuterated triglycerides and elucidation of fragmentation mechanisms. Lipids 1970; 5:869-77. [PMID: 5484201 DOI: 10.1007/bf02531118] [Citation(s) in RCA: 67] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
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Norgård S, Aasen AJ, Liaaen-Jensen S. Bacterial carotenoids. 32. C50-carotenoids 6. Carotenoids from Corynebacterium poinsettiae including four new C50-diols. Acta Chem Scand 1970; 24:2183-97. [PMID: 5485033 DOI: 10.3891/acta.chem.scand.24-2183] [Citation(s) in RCA: 36] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
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Abstract
Turneforcidine has been
prepared by the oxidation of methyl 7α-hydroxy- 8α-pyrrolizidine-1α-carboxylate
to the 7-keto compound and stepwise reduction with hydrogen/platinum and
lithium aluminium hydride. 7β- Hydroxy-8α-pyrrolizidine-1β-carboxylic
acid is not epimerized by alkali but converted into the stable γ-lactone
(VI).
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Aasen AJ, Culvenor CCJ, Finnie EP, Kellock AW, Smith LW. Alkaloids as a possible cause of ryegrass staggers in grazing livestock. ACTA ACUST UNITED AC 1969. [DOI: 10.1071/ar9690071] [Citation(s) in RCA: 33] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
Ryegrass staggers has been observed in sheep and cattle grazing pastures consisting solely of ryegrass seedlings or new shoots. Ryegrass from these toxic pastures contained a much higher alkaloid content (0.15–0.25%) than more mature grass (0.02–0.06%). A high alkaloid content appears to occur consistently in seedlings and new shoots. The alkaloid content of seedlings rises to a maximum at the sixth to the eighth day after germination and then falls. In the decline period and probably in mature grass, the alkaloid content is subject to wide daily fluctuation thought to be due to meteorological factors. In mature grass the alkaloid is nearly all perloline, but in seedlings halostachine (Ph–CHOH–CH2–NHCH3) may also be present as a major constituent. Parenteral administration of perloline to guinea-pigs and sheep produces effects resembling the symptoms of ryegrass staggers and including tetanic spasm, at a dose level of 30 mg/kg which could be attained in sheep grazing toxic grass. On oral administration at 100–200 mg/kg, perloline produces the same effects in guinea-pigs out has no effect in sheep. Halostachine is known to have sympathomimetic properties but produced only mild effects in sheep and guinea-pigs at similar doses. The two alkaloids together, given either simultaneously by the oral route or in sequence (halostachine intravenously followed by perloline orally), did not lead to disturbances resembling staggers.
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Aasen AJ, Francis GW, Liaaen-Jensen S, Heinegård D, Balaban AT, Craig JC. Bacterial Carotenoids. XXIX. The Carotenoids of two Yellow Halophilic Cocci - Including a New Glycosidic Methyl Apo-lycopenoate. ACTA ACUST UNITED AC 1969. [DOI: 10.3891/acta.chem.scand.23-2605] [Citation(s) in RCA: 23] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
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Aasen AJ, Culvenor CCJ. Abnormally low vicinal coupling constants for O-CH-CH in a highly strained five-membered-ring ether; The identity of loline and festucine. Aust J Chem 1969. [DOI: 10.1071/ch9692021] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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Aasen AJ, Jensen SL, Dam H, Brunvoll J, Hagen G. Bacterial Carotenoids. XXIV. The Carotenoids of Thiorhodaceae 7. Cross-conjugated Carotenals. ACTA ACUST UNITED AC 1967. [DOI: 10.3891/acta.chem.scand.21-2185] [Citation(s) in RCA: 38] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
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