the silica boron sulfuric acid nanoparticles (sbsans) as an efficient heterogeneous solid acid catalyst with both brønsted and lewis acidic sites catalyzed the preparation of bis-4-hydroxycoumarin derivatives using reaction of aldehydes and 4-hydroxycoumarin under mild and solvent-free condition at room temperature. this new and efficient methodology has advantages in comparison with currently ...

A spectrophotometric method using umbelliferone derivatives has been developed for the study of enzymic activites of mycobacteria. Arylsulphatase activity can be estimated in six hours rather than in 10 days as in the conventional method. The technique may be applied to a study of whole cells or to cell-free extracts.

In the present work we report on the contribution of the coumarin moiety to tyrosinase inhibition. Coumarin-resveratrol hybrids 1-8 have been resynthesized to investigate the structure-activity relationships and the IC(50) values of these compounds were measured. The results showed that these compounds exhibited tyrosinase inhibitory activity. Compound 3-(3',4',5'-trihydroxyphenyl)-6,8-dihydrox...

Synthesis and chemiluminescent properties of a new 1,2-dioxetane chemiluminophore bearing a 7-hydroxycoumarin moiety are presented. The 1,2-dioxetane decomposition ended up with strong and long-lived emission of light. This new structure opens way to the development of a new generation of bright chemiluminescent bio-probes.

Testosterone and 7-ethoxycoumarin were used as substrates to quantify the maintenance of phase I and II enzymes in precision-cut rat liver slices in dynamic organ culture. Testosterone hydroxylations, 7-ethoxycoumarin O-deethylation, 7-hydroxycoumarin sulfate, and 7-hydroxycoumarin glucuronide formation were all maintained at initial levels in the slice incubation media after incubation for up ...

Oxidation of p-coumarate at the ortho-position is a key step to form umbelliferone. A tracer analysis using (18)O2 was performed in order to take information about the formation of umbelliferone in the root tissue of sweet potato. Mass fragmentation experiments revealed incorporation of an 18O atom into the 1-position of umbelliferone. This result indicates that the lactone of umbelliferone is ...

Micro-organisms have been isolated that can utilize o-coumaric acid as a sole carbon source with the subsequent production of 4-hydroxycoumarin and dicoumarol. One of these organisms, Penicillium jenseni, has been used to examine the biosynthesis of dicoumarol. Certain thermophilic fungi have also been found that can convert o-coumaric acid into dicoumarol.

With the aim of studying the biosynthesis of psoralen and bergapten, two furocoumarins present in the leaves of “Ficus carica” (Moraceae), the Authors, continuing preceding researchs on this topic, have fed the leaves with the following labelled precursors: 4/,5/-dihydropsoralen, 4',5'-dihydrobergapten, 7-hydroxycoumarin, 5,7-dihydroxycoumarin and 5-methoxy-7-hydroxycoumarin. The results obtain...

Coumarin and its derivatives are well known for their anti-inflammatory and anti-oxidative effects. In this study, we synthesized 32 coumarin derivatives from commercially available 6-hydroxycoumarin (6HC) and 7-hydroxycoumarin (7HC) and examined their effects on lipopolysaccharide/interferon γ (LPS/IFNγ)-stimulated nitric oxide (NO) production in murine macrophage RAW264 cells. Among these der...

In this work, we attempted to synthesize thallium (III) oxide nano structures by direct thermal decomposition using thallium I phenylsuccinic acid coordination polymer [Tl(PsucH)]n as a precursor. Also, Tl2O3 nanoparticles have been characterized by scanning electron microscopy (SEM), X-Ray powder diffraction (XRD) and IR spectroscopy and then we report a simple and efficient method for the syn...