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PubMed2004

Inhibition of monoamine oxidases by coumarin-3-acyl derivatives: biological activity and computational study.

A series of coumarin-3-acyl derivatives have been synthesized and investigated for the ability to inhibit selectively monoamine oxidases. The coumarin-3-carboxylic acids, 2a-e, proved to be reversible and selective inhibitors of the MAO-B isoform, displaying pIC(50) values of particular interest: 2a shows pIC(50) 7.76 and a selectivity index (pS.I.) 2.94 and 2b shows pIC(50) 7.72 and a pS.I. of 2.80. The coumarin-3-acyl chlorides 3a-e showed high pIC(50) values against both MAO-A and MAO-B isoforms, 3d being the highest against MAO-B with a pIC(50) value of 8.00. In order to rationalize the activity/selectivity results, molecular descriptors were generated. Further insight about enzyme-inhibitor interaction was obtained by docking experiments with the MAO-B isoform.

Amine Oxidase (Copper-Containing)↗
PubMed2004

Amelioration of ferric nitrilotriacetate (Fe-NTA) induced renal oxidative stress and tumor promotion response by coumarin (1,2-benzopyrone) in Wistar rats.

In this study, we report the modulatory effect of coumarin (1,2-benzopyrone) on Ferric nitrilotriacetate (Fe-NTA) induced renal oxidative stress and tumor promotion response in rats. Fe-NTA (9 mg Fe/kg body weight, intraperitoneally) enhances renal lipid peroxidation, xanthine oxidase, gamma-glutamyl transpeptidase and hydrogen peroxide (H2O2) generation with reduction in antioxidant enzymes and renal glutathione content. It also enhances blood urea nitrogen, serum creatinine, ornithine decarboxylase (ODC) activity and thymidine [3H] incorporation into renal DNA. Prophylactic treatment of rats with coumarin (10 and 20 mg/kg body weight) resulted in significant recovery of antioxidant enzymes (P < 0.001) and renal glutathione content (P < 0.01). There was also significant decrease in gamma-glutamyl transpeptidase, lipid peroxidation, xanthine oxidase, H2O2 generation, blood urea nitrogen, serum creatinine, renal ODC activity and DNA synthesis (P < 0.001) Thus, our results show that coumarin is a potent chemopreventive agent and suppresses Fe-NTA induced nephrotoxicity in Wistar rats.

Animals↗
PubMed2004

Redifferentiation of human hepatoma cells induced by synthesized coumarin.

The effects of synthesized 7-OH-4-CH(3)-coumarin on proliferation and differentiation of human hepatoma carcinoma cell line, SMMC-7721, were examined. Results showed that 7-OH-4-CH(3)-coumarin suppressed the proliferation of the SMMC-7721 cells in a dose-dependent manner, with an IC(50) value of 356 +/- 1.8 .M, while concentrations< or =200 mM could trigger differentiation. After treatment with this compound at 100 mM, the growth curve of human hepatoma cells decreased markedly. When treated with 50 and 100 mM, the cells' electrophoresis rate decreased from 2.2 mm/s/V/cm in the control group to 1.5 and 1.8 mm/s/V/cm, respectively, and the alpha-fetoprotein content decreased from 123 ng/mg in the control group to 68 and 45 ng/mg, respectively. The microvilli on the surface of treated cells were also reduced. All the above indexes related to cell malignancy were alleviated significantly. Results showed that 7-OH-4-CH(3)-coumarin could reverse human hepatoma cells' malignant phenotypic characteristics and induce redifferentiation.

Carcinoma, Hepatocellular↗
PubMed2004

Preparative isolation and purification of coumarins from Peucedanum praeruptorum Dunn by high-speed counter-current chromatography.

A preparative high-speed counter-current chromatography (HSCCC) method for isolation and purification of coumarins from Peucedanum praeruptorum Dunn (Baihuaqianhu in Chinese) was successfully established by using light petroleum-ethyl acetate-methanol-water as the two-phase solvent system in gradient elution mode. The upper phase of light petroleum-ethyl acetate-methanol-water (5:5:5:5, v/v) was used as the stationary phase of HSCCC. The mobile phase used in HSCCC was the lower phase of light petroleum-ethyl acetate-methanol-water (5:5:5:5, v/v) and light petroleum-ethyl acetate-methanol-water (5:5:6.5:3.5, v/v) that was changed in gradient. Four kinds of coumarins and another unknown compound were obtained and yielded 5.3 mg of qianhucoumarin D, 7.7 mg of Pd-Ib, 35.8 mg of (+)-praeruptorin A, 31.9 mg of (+)-praeruptorin B and 6.4 mg of unknown compound with the purity of 98.6%, 92.8%, 99.5%, 99.4% and 99.8% in one-step separation, respectively. The structures of the coumarins were identified by 1H NMR and 13C NMR.

Apiaceae↗
PubMed2005

Retention of substituted coumarins using immobilized artificial membrane (IAM) chromatography: a comparative study with n-octanol partitioning and reversed-phase HPLC and TLC.

The chromatographic indices log k(wIAM) have been determined by HPLC on an immobilized artificial membrane column for a set of coumarin derivatives. The investigated compounds contain substituted amidoximes, or substituted heterocycles directly attached to the coumarinic skeleton. The log k(wIAM) values were compared to previously reported data of octanol-water partition coefficients and extrapolated capacity factors determined by reversed phase HPLC and TLC. The log k(wIAM) values of the investigated compounds were found to be comparable with the corresponding log P values, although they constitute a lower lipophilicity scale due to the reduced hydrophobic environment of the IAM stationary phase. These features were exemplified in their interrelationship with a slope close to unity and a large negative intercept. In contrast their comparison with the corresponding HPLC and RP-TLC capacity factors revealed differences in the retention mechanism reflected in slopes lower than unity, which were postulated to be due to secondary interactions under the reversed phase chromatographic conditions. However, conformational effects in the molecular structures of the coumarin derivatives were found to have a similar impact in their affinity for the IAM and octadecyl silane stationary phases, while they did not affect their octanol-water partitioning.

1-Octanol↗
PubMed2006

Enhanced resistance to Salmonella enterica serovar Typhimurium infection in mice after coumarin treatment.

Coumarin and its derivatives are naturally occurring substances with multiple biological activities. Here we demonstrate that prophylactic peroral administration of coumarin or 7-hydroxycoumarin (7-OHC) enhances resistance to subsequent lethal Salmonella enterica Serovar Typhimurium infection in mice. 7-OHC decreased bacterial load in liver and spleen, and enhanced phagocytosis and bacterial killing by macrophages when applied in vitro and in vivo. 7-OHC treatment induced significant NO release in peritoneal macrophage cultures. The observed protective effect correlated with the induction of Th1-associated cytokines, such as IL-12, IFN-gamma, and TNF-alpha. These data demonstrate a clear immunomodulatory potential of coumarins which might have important therapeutic implications to enhance resistance to infection.

Animals↗
PubMed2005

Photophysical and photochemical study of laser-dye coumarin-481 and its photoproduct in solution.

An ultraviolet light-induced photophysical and Photochemical changes of coumarin-481 in cyclohexane have been studied by photolysis technique at room temperature, due to its potential applications in photonics, photochemistry, and electronic spectroscopy. During the optical pumping, coumarin-481 showed photochemical changes, therefore as the concentration of coumarin-481 decreased, a photoproduct concentration increased rapidly. An absorption band of the product was observed at around 250 nm. Photoproduct emission spectra characteristics show that photoproduct molecules can also be used as a laser-dye at different emission frequency.

Coumarins↗
PubMed2001

Fluorescent coumarin-labeled nucleotides to measure ADP release from actomyosin.

Several coumarin-labeled nucleotides have been synthesized, based on 2'(3')-O-(2-aminoethyl)carbamoyl-ATP (edaATP). The fluorescent coumarins coupled with the free amino group are 7-diethylaminocoumarin-3-carboxylic acid (to give deac-edaATP), coumarin 343 (but-edaATP) and 7-ethylamino-8-bromocoumarin-3-carboxylic acid (mbc-edaATP). The carbamoyl linkage of these nucleotide analogs undergoes interconversion between 2'- and 3'-hydroxyl attachment very slowly, so that the 2'- and 3'-isomers were separated and stored with minimal equilibration. 3'-Deac-edaADP had fluorescence excitation and emission maxima at 430 nm and 477 nm, with a fluorescence quantum yield of 0.012. The equivalent data for 3'-but-edaADP are 445 nm, 494 nm, and 0.51, respectively, and for 3'-mbc-edaADP, 405 nm, 464 nm, and 0.62. The interaction with skeletal myosin subfragment 1 was measured in the absence and presence of actin. In each case the fluorescence was decreased when bound to subfragment 1, 3-fold for 3'-deac-edaADP, 7-fold for 3'-but-edaADP, and 11-fold for 3'-mbc-edaADP. Steady-state ATPase measurements and the kinetics of binding and release of nucleotides were similar to those reported for the natural nucleotide. Large fluorescence changes could be observed for the release of these analogs from actomyosin subfragment 1, enabling a direct measurement of the kinetics of this process. In the case of 3'-deac-edaADP a rate constant of 474 s(-1) was measured (at pH 7.0, 20 degrees C, and low ionic strength).

Actomyosin↗
PubMed1987

[Simultaneous analysis of aromatic aldehydes and coumarins with high pressure liquid chromatography. Application to wines and brandies stored in oak barrels].

Aromatic aldehydes (vanillin, syringaldehyde, coniferaldehyde and sinapaldehyde) and coumarins (esculetin, umbelliferone, scopoletin and methylumbelliferone) are natural wood compounds. Storage of wines and brandies in oak barrels increases notably aldehydes and coumarins (particularly scopoletin) concentrations. These compounds were separated by high-performance liquid chromatography, on hydrocarbon bonded reversed-phase packings, with a water-acetonitrile elution gradient. They were first extracted from wines and brandies by diethyl ether and then injected on chromatographic column. A double detection was used to determine simultaneously aromatic aldehydes and coumarins by UV absorption and fluorescence respectively.

Alcoholic Beverages↗
PubMed2002

Coumarin glucosides from Cruciata taurica.

Two new coumarin glycosides (1 and 2) along with two known coumarin glucosides, daphnin (3) and daphnetin glucoside (4) were isolated from the aerial parts of Cruciata taurica. The structures of the new compounds were elucidated by spectral methods and chemical means as 7-O-(6' -acetoxy-beta-D-glucopyranosyl)-8-hydroxycoumarin (1) and 7-O-[6 '-O-(3'',4''-dihydroxycinnamoyl)-beta-D-glucopyranosyl]-8-hydroxycoumarin (2). The phylogenetic significance of coumarins in C. taurica was discussed.

Coumarins↗
PubMed2000

Coumarins from Ferulago capillaris and F. brachyloba.

Four new coumarins, (+)-senecioylprangol, (-)-3'-senecioyloxymarmesin, (+)-3'-hydroxyprantschimgin and (+)-2"-senecioyloxymarmesin, besides 12 known coumarins have been isolated from two Ferulago species. Their structures have been established by spectroscopic methods and partial synthesis. New synthetic 3'-oxocoumarins are also described. There is a remarkable difference in the contents of the most abundant coumarins found in the roots of both species: osthol and aurapten are specific to F. capillaris and F. brachyloba, respectively.

Apiaceae↗
PubMed1983

Inherited protein C deficiency and coumarin-responsive chronic relapsing purpura fulminans in a newborn infant.

A coumarin-responsive chronic relapsing purpura fulminans syndrome is described in a protein-C-deficient newborn infant. Episodes of acute disseminated intravascular coagulation (DIC) and cutaneous gangrene, which first appeared at age 11 h, were effectively controlled for 28 months with transfusions of fresh-frozen plasma. Cryoprecipitate and cryoprecipitate-poor plasma induced remissions as long as those induced by fresh-frozen plasma (less than or equal to 72 h). Coumarins sustained a cryoprecipitate-induced remission for 19 days: they were then electively discontinued and 17 h later the patient had an acute exacerbation of DIC with haemorrhaging. Family studies showed protein C levels of 31-40% in the subject's symptom-free mother and full and half brothers. DIC, the coumarin effect, and the inherited protein C abnormality appear to have contributed to the extremely low plasma levels (less than or equal to 6%) of protein C in the patient. This experience suggests that protein C deficiency may greatly compromise the ability of newborn infants to control consumptive disorders.

Child↗
PubMed1999

Highly sensitive high-performance liquid chromatographic assay for coumarin 7-hydroxylation and 7-ethoxycoumarin O-deethylation by human liver cytochrome P450 enzymes.

A highly sensitive method for the determination of coumarin 7-hydroxylation and 7-ethoxycoumarin O-deethylation by human cytochrome P450 (P450 or CYP) enzymes was developed using high-performance liquid chromatography (HPLC). The newly developed HPLC method was found to be about 100-fold more sensitive than the previous spectrofluorimetric method in detecting the metabolite 7-hydroxycoumarin (umbelliferone). With this high sensitivity, the kinetics of coumarin 7-hydroxylation and 7-ethoxycoumarin O-deethylation catalyzed by human liver microsomal and recombinant P450 enzymes were determined more precisely. With 36 different substrate concentrations in these two reactions, coumarin 7-hydroxylation was found to be catalyzed mainly by a single enzyme CYP2A6 and 7-ethoxycoumarin was oxidized by at least two enzymes CYP2E1 and CYP1A2 in human liver microsomes.

Chromatography, High Pressure Liquid↗
PubMedDate not supplied

13C CP MAS NMR and GIAO-CHF calculations of coumarins.

13C cross-polarization magic-angle spinning NMR spectra were recorded for a series of solid coumarins. Ab initio calculations of shielding constants were performed with the use of GIAO-CHF method. The combined CPMAS NMR and theoretical approach was successful in characterizing solid-state conformations of coumarins; a relationship sigma (ppm) = -1.032 xdelta + 205.28 (R(2) = 0.9845) can be used to obtain structural information for coumarins, for which solid-state NMR or crystal structure data are not available.

Carbon Isotopes↗
PubMed1998

Hepatoprotective and nitric oxide production inhibitory activities of coumarin and polyacetylene constituents from the roots of Angelica furcijuga.

The methanolic extract from the roots of Angelica furcijuga KITAGAWA was found to exhibit protective effects on liver injury induced by D-galactosamine (D-GalN) and lipopolysaccharide (LPS). From the methanolic extract, seventeen coumarins, two phenylpropanoids, and two polyacetylenes were isolated and examined their in vitro and in vivo hepatoprotective effects and inhibitory activity of NO production in macrophages. A acylated khellactone, isoepoxypteryxin, showed protective activity against D-GalN-induced cytotoxicity in primary cultured rat hepatocytes. On the other hand, six acylated khellactones (hyuganins A, B, C, and D, anomalin, isopteryxin) and two polyacetylenes [(-)-falcarinol and falcarindiol] strongly inhibited NO production induced by LPS in cultured mouse peritoneal macrophages, and also other acylated khellactones (isoepoxypteryxin, pteryxin, and suksdorfin) and a coumarin glycosides (praeroside II) were found to show the activity. By comparison of the inhibitory activities for acylated khellactones with those for other coumarins, acyl groups were found to be essential to exerting potent activity.

Acetylene↗
PubMed2000

Coumarin inhibitors of gyrase B with N-propargyloxy-carbamate as an effective pyrrole bioisostere.

The synthesis and biological profile in vitro of a series of coumarin inhibitors of gyrase B bearing a N-propargyloxycarbamate at C-3' of noviose is presented. Replacement of the 5-methylpyrrole-2-carboxylate of coumarin drugs with an N-propargyloxycarbamate bioisostere leads to analogues with improved antibacterial activity. Analysis of crystal structures of coumarin antibiotics with the 24 kDa N-terminal domain of the gyrase B protein provides a rational for the excellent inhibitory potency of C-3' N-alkoxycarbamates.

Anti-Bacterial Agents↗
PubMed2000

Coumarinic derivatives as mechanism-based inhibitors of alpha-chymotrypsin and human leukocyte elastase.

Novel coumarinic derivatives were synthesized and tested for their inhibitory potency toward alpha-CT and HLE. Cycloalkyl esters and amides were found to be essentially inactive on both enzymes. On the opposite, aromatic esters strongly inactivated alpha-CT whereas HLE was less efficiently inhibited with dichlorophenyl ester derivatives (kinact/K(I) = 4000 M(-1) s(-1) for 36). Representative examples of amide, ester, thioester and ketone derivatives were prepared in order to evaluate the influence of the link between the coumarinic ring and the phenyl side chain. The irreversible inactivation of alpha-CT by 6-chloromethyl derivatives should be due to alkylation of a histidine residue as suggested by the amino acid analysis of the modified chymotrypsin. Conversely the inhibition of HLE was transient. Intrinsic reactivity of coumarins has been calculated using a model of a nucleophilic reaction between the ligand and the couple methanol-water. From this calculation, it appears that differences in the inhibitory potency expressed by these molecules cannot only be explained by differences in the reactivity of the lactonic carbonyl group toward the nucleophilic attack.

Chymotrypsin↗