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This article is available online at http://dmd.aspetjournals.org ABSTRACT:The female flowers of hops are used throughout the world as a flavoring agent for beer. Recently, there has been increasing interest in the potential estrogenic properties of hop extracts. Among the possible estrogenic compounds in hops, 8-prenylnaringenin is perhaps most significant due to its high in vitro potency exceeding that of other known phytoestrogens. Since data regarding the pharmacokinetic properties of this compound are lacking, we investigated the in vitro metabolism of 8-prenylnaringenin by human liver microsomes. A total of 12 metabolites were identified, and biotransformation occurred on the prenyl group and the flavanone skeleton. The major site of oxidation was on the terminal methyl groups, and of the two possible isomers, the trans isomer was more abundant. The double bond on the prenyl group was also oxidized to an epoxide that was opened by intramolecular reaction with the neighboring hydroxyl group. On the flavanone skeleton, the major site of oxidation was at 3 position on the B ring. Other metabolites included oxidation at carbon-3 as well as desaturation of the C ring to produce 8-prenylapigenin. An unusual hydroxy quinone product formed by ipso hydroxylation of the B ring of 8-prenylnaringenin was also detected. This product was probably an intermediate for the B ring cleavage product, 8-prenylchromone.

Preparation and photopolymerization of a decylmethylimidazolium ionic liquid (IL) that possesses an acrylate counteranion are described. This IL monomer self-assembles upon addition of water and can be copolymerized with poly(ethylene glycol) diacrylate (PEGDA) in the presence of a photoinitiator, forming a mechanically durable material that adopts a lamellar structure with in-plane hexagonally ordered pores, as evidenced by small-angle X-ray scattering (SAXS). Thermogravimetric analysis, the extent of polymerization, and solubility−swelling studies indicate the formation of a network copolymer of the IL monomer and the PEGDA. Additional evidence for the formation of a nanostructured copolymer is provided by evaluating the product formed by replacement of the IL monomer with the nonpolymerizable analogue, decylmethylimidazolium chloride. The results demonstrate the possibility of designing a self-assembled amiphiphilic bilayer architecture that is reinforced by polymerization and cross-linking.

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A self-supporting biomimetic chemical hydrogel that can be reversibly swollen in water is described. An aqueous dispersion of a diacrylate end-derivatized PEO-PPO-PEO macromer, a saturated phospholipid, and a zwitterionic co-surfactant self-assembles into a multilamellar-structured physical gel at room temperature as determined by SAXS. The addition of a water soluble PEGDA co-monomer and photoinitiator within the water layers does not alter the self-assembled structure. ATR/FT-IR spectroscopy reveals that photoirradiation initiates the crosslinking between the acrylate end groups on the macromer with the PEGDA, forming a polymeric network within the aqueous domains. The primitive cytoskeleton mimic serves to stabilize the amphiphile bilayer, converting the physical gel into an elastic self-supporting chemical gel. Storage under ambient conditions causes dehydration of the hydrogel to 5 wt % water which can be reversed by swelling in water. The fully water swollen gel (85 wt % water) remains self-supporting but converts to a non-lamellar structure. As water is lost the chemical gel regains its lamellar structure. Incubation of the hydrogel in nonpolar organic solvents that do not dissolve the uncrosslinked lipid component (hexane) allow for swelling without loss of structural integrity. Chloroform, which readily solubilizes the lipid, causes irreversible loss of the lamellar structure.