Microwave-mediated synthesis of labeled nucleotides with utility in the synthesis of DNA probes.

A novel method of linking haptens to deoxycytidine 5'-triphosphate via microwave-mediated bisulfate-catalyzed transamination with hydrazine has been developed. This method enables the tethering of small molecule haptens to dCTP via a discrete polyethylene glycol (PEG) spacer, yielding N(4)-aminodeoxycytidine 5'-triphosphate-dPEG-haptens. This synthetic approach employs microwave-catalyzed hydrazinolysis that enables the attachment of spacers via hydrazine linkages.

Deguelin-induced inhibition of cyclooxygenase-2 expression in human bronchial epithelial cells.

The increased expression of cyclooxygenase (COX)-2 significantly enhances carcinogenesis and inflammatory reactions, and its regulation may be a reasonable target for cancer chemoprevention. We demonstrated previously that deguelin inhibits proliferation of premalignant human bronchial epithelial (HBE) cells, such as 1799 cells and squamous HBE cells, by regulating phosphatidylinositol-3-kinase Akt activity, which is involved in COX-2 expression. We sought to determine the effect of deguelin on COX-2 expression in squamous HBE cells.

Increasing the throughput and productivity of Caco-2 cell permeability assays using liquid chromatography-mass spectrometry: application to resveratrol absorption and metabolism.

The Caco-2 cell monolayer permeability assay has become a standard model of human intestinal absorption and transport. This paper reviews recent progress in increasing the throughput of Caco-2 cell monolayer assays and in expanding the scope of this assay to include modeling intestinal drug metabolism. The state-of-the-art in Caco-2 cell monolayer permeability assays combines multi-well plates fitted with semi-permeable inserts on which Caco-2 cells have been cultured with liquid chromatography-mass spectrometry (LC-MS) or LC-tandem mass spectrometry (LC-MS-MS) for the quantitative analysis of test compounds and the identification of their intestinal metabolites.

Effects of deguelin on the phosphatidylinositol 3-kinase/Akt pathway and apoptosis in premalignant human bronchial epithelial cells.

Background: Because lung cancer is the leading cause of cancer-related death, new approaches for preventing and controlling the disease are needed. Chemoprevention approaches are both feasible and effective. We evaluated the potential of deguelin, a natural plant product, as a lung cancer chemopreventive agent and investigated its mechanism of action.

Liquid chromatography/tandem mass spectrometric determination of inhibition of human cytochrome P450 isozymes by resveratrol and resveratrol-3-sulfate.

trans-Resveratrol, a phenolic phytoalexin occurring in grapes, wine, peanuts, and cranberries, has been reported to both have anticarcinogenic, antioxidative, phytoestrogenic, and cardioprotective activities, and to be a weak inhibitor of cytochrome P450 (CYP)3A4, which might have significance for drug-drug interactions. Since trans-resveratrol is rapidly converted in vivo to primarily trans-resveratrol-3-sulfate, a rapid, selective, and sensitive method using liquid chromatography/tandem mass spectrometry (LC/MS/MS) was developed to investigate human cytochrome P450 inhibition by trans-resveratrol-3-sulfate. Effects of trans-resveratrol and trans-resveratrol-3-sulfate on the metabolism of selective cytochrome P450 substrates (CYP1A2/ethoxyresorufin, CYP2C9/diclofenac, CYP2C19/(S)-mephenytoin, CYP2D6/bufuralol, CYP3A4/testosterone) were monitored using cDNA-expressed human recombinant isozymes.

Deguelin suppresses the formation of carcinogen-induced aberrant crypt foci in the colon of CF-1 mice.

Deguelin [(7aS,BaS)-13,13a-dihydro-9,10-dimethoxy-3,3-dimethyl-3H-Bis[1]benzopyrano[3,4-b:6',5'-e]pyran-7(7aH)-one], a naturally occurring rotenone, has shown chemopreventive efficacy in several in vivo and in vitro models. In this report, the effectiveness of deguelin at inhibiting the development of AOM-induced colonic ACF was investigated in CF-1 mice. Loss of hex activity was assessed as a second biomarker.

Human, rat, and mouse metabolism of resveratrol.

Purpose: Resveratrol, a phenolic phytoalexin occurring in grapes, wine, peanuts, and cranberries, has been reported to have anticarcinogenic, antioxidative, phytoestrogenic, and cardioprotective activities. Because little is known about the metabolism of this potentially important compound, the in vitro and in vivo metabolism of trans-resveratrol were investigated.

Methods: The in vitro experiments included incubation with human liver microsomes, human hepatocytes, and rat hepatocytes and the in vivo studies included oral or intraperitoneal administration of resveratrol to rats and mice.