Prenylated chalcone xanthohumol associates with histones in breast cancer cells--a novel target identified by a monoclonal antibody.

Scope: The intracellular fate of xanthohumol (XN) from hops is an underexplored field in the research for the molecular mechanisms causing its wide range of effects in chemoprevention and gene expression involved in hepatic metabolism.

Methods And Results: We aimed to elucidate possible targets for binding of XN in a human mammary carcinoma cell line (MCF-7/6), using a mAB. We investigated the overall solubility and stability of XN in growth medium and the cellular uptake and distribution of XN in MCF-7/6 cells using an optimized immunocytochemistry technique.

Production of monoclonal antibodies against hop-derived (Humulus lupulus L.) prenylflavonoids and the development of immunoassays.

Monoclonal antibodies against the hop-derived prenylated chalcone xanthohumol (X) and the prenylated flavonoids isoxanthohumol (IX) and 8-prenylnaringenin (8-PN) were developed. Carboxylic acid haptens of X, IX and 8-PN were synthesized by linking a spacer to their C4'-OH group followed by subsequent coupling to bovine serum albumin (BSA) to form conjugates that were employed as immunogens in BALB/c mice to raise antibodies. The monoclonal antibodies that were secreted from the established hybridoma cell lines proved, in cross-reactivity studies, to possess highly specific binding capacities in an optimized competitive indirect ELISA.

Development of a high-throughput LC/APCI-MS method for the determination of thirteen phytoestrogens including gut microbial metabolites in human urine and serum.

The investigation into the potential usefulness of phytoestrogens in the treatment of menopausal symptoms requires large-scale clinical trials that involve rapid, validated assays for the characterization and quantification of the phytoestrogenic precursors and their metabolites in biological matrices, as large interindividual differences in metabolism and bioavailability have been reported. Consequently, a new sensitive high-performance liquid chromatography-mass spectrometry method (HPLC-MS) for the quantitative determination of thirteen phytoestrogens including their most important gut microbial metabolites (genistein, daidzein, equol, dihydrodaidzein, O-desmethylangolensin, coumestrol, secoisolariciresinol, matairesinol, enterodiol, enterolactone, isoxanthohumol, xanthohumol and 8-prenylnaringenin) in human urine and serum within one single analytical run was developed. The method uses a simple sample preparation procedure consisting of enzymatic deconjugation followed by liquid-liquid extraction (LLE) or solid-phase extraction (SPE) for urine or serum, respectively.

Cosupplementation of isoflavones, prenylflavonoids, and lignans alters human exposure to phytoestrogen-derived 17beta-estradiol equivalents.

The microbial metabolism of dietary phytoestrogens varies considerably among individuals and influences the final exposure to bioactive compounds. In view of the increasing number of food supplements combining several classes of phytoestrogens, the microbial potential to activate various proestrogens within an individual was evaluated in 3 randomized dietary crossovers. Treatment allocation was based on participants' eligibility (>45% in vitro bioactivation of >or=2 separate proestrogens by fecal cultures; n = 40/100).