Showing papers on "Isopimpinellin published in 2005"

Melanogenesis stimulation in murine b16 melanoma cells by umberiferae plant extracts and their coumarin constituents.

Abstract: Melanogenesis stimulation activities of seven ethanolic extracts obtained from Umbelliferae plants used as Chinese crude drugs, namely the roots of Angelica dahurica BENTH. et HOOK., A. biserrata SHEN et YUAN, Notopterygium incisum TING, Heracleum lanatum MICHX., and H. candicans WALL., and the fruits of Cinidium monnieri (L.) CUSSON and C. formosanum YABE, were examined by using cultured murine B16 melanoma cells. Among them, the extract (5, 25 microg/ml) of H. lanatum showed a potent stimulatory effect on melanogenesis with significant enhancement of cell proliferation in a dose-dependent manner. The melanogenesis stimulatory effects of sixteen coumarins (1-16) isolated from the seven Umbelliferae crude drugs were also examined. Among them, linear-furocoumarins [psoralen (1), xanthotoxin (2), bergapten (3), and isopimpinellin (4)] and angular-furocoumarin [sphondin (13)] exhibited potent melanogenesis stimulation activity. From the view point of structure-activity relationships, it may be assumed that a linear-furocoumarin ring having a hydrogen and/or methoxyl group at 5 and 8 positions such as 1, 2, 3 and 4 was preferable for the melanogenesis stimulation activity. The introduction of a prenyl group into the furocoumarin ring was disadvantageous. Coumarin derivatives having a simple coumarin ring were inactive.

Coumarins are competitive inhibitors of cytochrome P450 1B1, with equal potency for allelic variants.

Abstract: Objectives Coumarins are naturally occurring chemicals with potential as chemopreventive agents, several with known action on the cytochrome P450 1A family. We examined whether cytochrome P450 1B1 (CYP1B1) was inhibited by coumarins, whether such inhibition was competitive, and whether inhibition varied between common polymorphic variants of this enzyme. Methods We tested the inhibition properties of four coumarins, bergamottin, isopimpinellin, isoimperatorin, and imperatorin in an assay for oxidation of (-)benzo[a]pyrene-7R-trans-7,8-dihyrodiol (B[a]P-7,8-diol) by CYP1B1 using yeast-microsome expressed enzymes. These assays were performed with wild-type enzyme and five single-amino acid polymorphic variants. Results All four coumarins are competitive inhibitors of CYP1B1, with Ki values equal to 587, 11, 6 and 1 muM respectively. Inhibition parameters were consistent between five haplotypes of CYP1B1, three representing common haplotypes in Asians, African-Americans and European-Americans, and two with baseline kinetic parameters previously shown to be potentially different from wild-type. Conclusions Coumarins are capable of inhibiting carcinogen activation by CYP1B1 with varying potencies, and their efficacy as chemopreventive agents is not likely to be affected by polymorphism in this enzyme.

Coumarin Derivatives from Esenbeckia grandiflora. and its Larvicidal Activity Against Aedes aegypti.

Abstract: From a hexane fraction prepared from the roots of Esenbeckia grandiflora Mart, effective against fourth instar larvae of Aedes aegypti L (LC50 10823 ppm), eight coumarin derivatives [daphnetin 7-methyl-8-(3,3-dimethylallyl) ether, a mixture containing pimpinellin eight one of its photodimerization product, 5-senecioyl-xanthotoxin, 3-(1′,1′)-dimethylallylcolumbianetin, swietenocoumarin B, isopimpinellin, xanthotoxin, and 5-(1′-hydroxyisopentenyl)bergapten] were isolated in addition to sitosterol and sitostenone The mixture containing pimpinellin and its photodimerization product was effective against fourth instar larvae (LC50 at 4577 ppm), and a mixture of pimpinellin and swietenocoumarin B showed a LC50 value of 6223 ppm All isolated compounds were identified on the basis of the spectral data including 2D experiments Furthermore, previously unreported spectral data for some compounds are given

Accumulation of biologically active furanocoumarins in agitated cultures of Ruta graveolens L. and Ruta graveolens ssp. divaricata (Tenore) Gams.

Abstract: This study was designed to investigate the dynamics of accumulation of linear furanocoumarins (psoralen, bergapten, xanthotoxin, isopimpinellin, imperatorin) and their biogenetic precursor, umbelliferone, in agitated cultures of Ruta graveolens L. and Ruta graveolens ssp. divaricata (Tenore) Gams during 6-week growth cycles. The metabolites under study were almost exclusively accumulated in the cultured biomass. The total content of all metabolites increased 4.8- and 2.0-fold, in R. graveolens and R. graveolens ssp. divaricata cultures, respectively. Xanthotoxin and bergapten, which are the most important therapeutic compounds, were the dominating metabolites in cultures of both plants. The maximum content of xanthotoxin (25.0 mg/100g dry wt.) and bergapten (18.4mg/100g dry wt) and the maximum content of all metabolites (64.0 mg/100 g dry wt) in R. graveolens ssp. divaricata callus obtained on the 35 t h culture day were relatively low. However, maximum contents of xanthotoxin (136.8 mg/100 g dry wt), bergapten (210.4 mg/100 g dry wt.) and isopimpinellin (96.7 mg/100 g dry wt), and total content of all metabolites in R. graveolens shoots (520.8 mg/100 g dry wt) obtained on the 42 n d culture day are interesting from a practical point of view.

Accumulation of biologically active furanocoumarins in Ruta graveolens ssp. divaricata (Tenore) Gams in vitro culture.

Abstract: The study was designed to investigate dynamics of accumulation of five linear furanocoumarins and umbelliferone in stationary liquid cultures of Ruta graveolens ssp. divaricata (Tenore) Gams during 6-week growth cycles. The contents of individual metabolites in biomass increased 1.8-3.5 times while their total content rose 2.3 times. Maximum contents of xanthotoxin, bergapten and isopimpinellin (112.3, 76.2 and 84.0mg/100g d.w., respectively) and maximum total content of all metabolites (283.4 mg/100 g d.w.), obtained on 35th culture day, are interesting from practical point of view.