Desmethylxanthohumol

Relevance of organic farming and effect of climatological conditions on the formation of alpha-acids, beta-acids, desmethylxanthohumol, and xanthohumol in hop (Humulus lupulus L.).[Pubmed:17199314]

J Agric Food Chem. 2007 Jan 10;55(1):61-6.

The concentrations of alpha-acids, beta-acids, Desmethylxanthohumol, and xanthohumol were monitored in the hop varieties Admiral (A), Wye Challenger (WC), and First Gold (FG) during the harvest seasons of 2003 through 2005. Hops grown under an organic regimen were compared to plants grown conventionally in hop fields in close vicinity. The concentrations of the key compounds depended very much on climatological conditions showing, in general, highest levels in poorest weather conditions (2004). Of the three varieties studied, FG was the only one showing a clear trend for higher concentrations of secondary metabolites under organic growing conditions than under conventional farming conditions. Cultivation of A and WC seems to be very sensitive to climatic conditions and environmental stresses caused by pests and diseases, thereby leading to various results. WC proved to be a rich source of bioactive chalcones, particularly Desmethylxanthohumol.

Synthesis and antioxidant evaluation of desmethylxanthohumol analogs and their dimers.[Pubmed:27688188]

Eur J Med Chem. 2017 Jan 5;125:335-345.

Four ring-closed analogs of natural prenylated chalcone Desmethylxanthohumol (1) and their dimers were synthesized from the commercially available 1-(2,4,6-trihydroxyphenyl)ethan-1-one in five and six linear steps, respectively. The structures of the eight new derivatives were confirmed using(1)H NMR, (13)C NMR and HRMS. The antioxidant activity of the new chalcone derivatives were evaluated in a PC12 cell model of H2O2-induced oxidative damage. The SAR studies suggested that the catechol motif was essential for the antioxidant activity. Moreover, the dimers showed better antioxidant activity than their corresponding monomers did. Among them, compound 14d was the most potent and increased PC12 cell viability from 25% to 85%. Flow cytometric analysis showed that compound 14d, the most potent compound, decreased the apoptotic PC12 cell percentage and significantly reduced the LDH release and 8-OHdG generation but increased the GSH levels in H2O2-treated PC12 cells. Furthermore, compound 14d had a higher FRAP value than that of gallic acid. It also reduced the stable ABTS(+) free radical with a lower EC50 than that of gallic acid.

Dynamic residual complexity of natural products by qHNMR: solution stability of desmethylxanthohumol.[Pubmed:19145555]

Planta Med. 2009 Jun;75(7):757-62.

The use of chromatographic assays to assess the residual complexity of materials that are purified from natural sources by chromatographic means is, in a sense, a case of the fox watching the henhouse. Beside their static residual complexity, which is intrinsic to their metabolic origin, biologically active natural materials can also be involved in chemical reactions that lead to dynamic residual complexity. The present study examines the dynamics of the hop prenylphenol, Desmethylxanthohumol (DMX), by means of quantitative (1)H-NMR (qHNMR) in a setting that mimics IN VITRO and physiological conditions. The experiments provide a comprehensive, time-resolved, and mechanistic picture of the spontaneous isomerization of DMX into congeneric flavanones, including their (1)H/(2)D isotopomers. Formation of the potent phytoestrogen, 8-prenylnaringenin (8PN), suggests that measurable estrogenic activity even of high-purity DMX is an artifact. Together with previously established qHNMR assays including purity activity relationships (PARs), dynamic qHNMR assays complement important steps of the post-isolation evaluation of natural products. Thus, qHNMR allows assessment of several unexpected effects that potentially break the assumed linkage between a single chemical entity (SCE) and biological endpoints.

Formation and accumulation of alpha-acids, beta-acids, desmethylxanthohumol, and xanthohumol during flowering of hops (Humulus lupulus L.).[Pubmed:12848522]

J Agric Food Chem. 2003 Jul 16;51(15):4436-41.

Important secondary metabolites, present in hops (Humulus lupulus L.), include alpha-acids and beta-acids, which are essential for the brewing of beer, as well as the prenylated chalcones, Desmethylxanthohumol, and xanthohumol, which exhibit interesting bioactive properties. Their formation and accumulation in five selected hop varieties, Wye Challenger, Wye Target, Golding, Admiral, and Whitbread Golding Variety, were quantitatively monitored by high-performance liquid chromatography using UV detection. All target compounds were present from the onset of flowering, not only in female hop cones but also in male inflorescences, albeit in low concentrations. During development from female inflorescences to cones, levels of alpha-acids, beta-acids, Desmethylxanthohumol, and xanthohumol gradually increased, while each hop variety exhibited individual accumulation rates. Furthermore, these compounds were present in leaves of fully grown hops as well. The study demonstrated that key compounds for flavor and potential beneficial health effects associated with beer not only reside in the glandular lupulin structures but also are distributed over various parts of the hop plant.