Development of a Novel Hapten for Radioimmunoassay of the Lignan, Enterolactone in Plasma (Serum). Total Synthesis of (±)-trans-5-Carboxymethoxyenterolactone and Several Analogues

Multicomponent, fragment-based synthesis of polyphenol-containing peptidomimetics and their inhibiting activity on beta-amyloid oligomerization

A new and short fragment-based approach towards artificial (but “natural-based”) complex polyphenols has been developed, exploiting the Ugi multicomponent reaction of phenol-containing simple substrates.

Design and validation of a novel immunological test for enterolactone

Enterolactone (ENL) is produced by the gut microflora from lignans found in edible plants. ENL is estrogenic with no effect on the E-screen test and is a natural Selected Estrogen Receptor Modulator (SERM) with health interests that have to be checked in clinical studies with bioavailability assessment. Two haptens of ENL were synthesized, with a spacer arm at the C5 position having either 2 or 4 carbon atoms (ENLΔ2 and ENLΔ4, respectively). Hapten coupling to bovine serum albumin (BSA) was characterized by MALDI mass spectrometry. Polyclonal antibodies were obtained against the BSA conjugates. Additional conjugates were generated by coupling to swine thyroglobulin (Thyr). Homologous and heterologous competitive ELISAs were developed with Thyr or BSA conjugates as coating. The best assays were validated on biological samples from mice. Both antibodies exhibited the same IC50 at 1.5 ng mL(-1) with a detection limit below 0.5 ng mL(-1). Most cross-reactions with structurally related lignans were lower than 0.03%. This new assay type is faster, more specific and more reliable than existing ones.

Mechanistic studies on regioselective dephosphorylation of phosphate prodrugs during a facile synthesis of antitumor phosphorylated 2-phenyl-6,7-methylenedioxy-1H-quinolin-4-one

Phosphorylation of 2-(3-hydroxy-5-methoxyphenyl)-6,7-methylenedioxy-1H-quinolin-4-one (1) afforded diphosphate 2. We found that, upon treatment with methanol under mild conditions, 2 can undergo facile and highly regioselective dephosphorylation to give the monophosphate 3, with a phosphate group remaining on the phenyl ring. The details of the dephosphorylation process were postulated and then probed by LC-MS and HPLC analyses. Furthermore, as a preliminary study, the water soluble monophosphate prodrug 4 was tested for antitumor activity against a MCF-7 xenograft nude mice model.

Asymmetric synthesis, stereochemistry and rearrangement reactions of naturally occurring 7′-hydroxylignano-9,9′-lactones

The asymmetric synthesis of a series of (7'S,8R,8'R)-7'-hydroxylignano-9,9'-lactones is presented, among them the mammalian lignan (7'S)-hydroxyenterolactone and (7'S)-parabenzlactone, allowing the stereochemistry of natural occurring (-)-parabenzlactone to be re-assigned. A hydroxylactone rearrangement and its possible mechanisms are discussed. Finally a brief survey of the current naming and numbering variants of 7'-hydroxylignano-9,9'-lactones is presented, along with a suggestion for harmonization of the nomenclature.

Stereospecific Pd(O)-Catalyzed Malonate Additions to Allylic Hydroxy Phosphonate Derivatives: A Formal Synthesis of (−)-Enterolactone

A combination of cross-metathesis and malonate addition was applied to a formal synthesis of the mammalian lignan enterolactone 5. The cross-metathesis of alkene 6 and phosphonate 3a gave the substituted allylic phosphonate 3d. The palladium-catalyzed addition of malonate 10d to the allylic phosphonate 3d was stereospecific and highly regioselective and yielded the vinyl phosphonate 11d. The vinyl phosphonate 11d was converted in two steps into the lactone 14, a known intermediate in the synthesis of enterolactone 5.

Analysis of phyto-oestrogens in biological matrices

A review covering different methods for the analysis of phyto-oestrogens in biological matrices is presented. Sample pretreatment and analysis of isoflavonoids and lignans by HPLC and GC with various detection methods are discussed. The immunoassay method is also briefly presented.

Review of the methods used in the determination of phytoestrogens

Interest in analytical methods for plant estrogens (phytoestrogens) has risen sharply in the past 10 years. In this review, we examine the existing analytical methods based on separations by gas-liquid chromatography, high-performance liquid chromatography and capillary electrophoresis in addition to methods of detection by ultraviolet absorption, fluorescence, electrochemical oxidation/reduction and mass spectrometry. These methods are compared with other methods of phytoestrogen analysis utilizing immunoassay approaches. The advantages and disadvantages of each of these methods are highlighted and potential areas for further development identified.

Enterolignans

A review with 114 references about mammalian lignans (enterolignans). Several aspects have been reviewed: the precursors of mammalian lignans and their biosynthesis, biological activities and health effects, metabolism (in vivo and in vitro) in human and animals, some synthetic strategies to obtain enterolignan skeleton types, including the synthesis of haptens and deuterated lignans, and finally an overview of the analytical methods to detect and quantify lignans in biological matrices and foods.