Xanthohumol from hop cones (Humulus lupulus L.) prevents ADP-induced platelet reactivity.

Hop cones (Humulus lupulus L.), very rich source of phenolic compounds, possessing anticancer, antioxidant and anti-inflammatory activities, are considered as beneficial diet ingredients improving human health. In this study, the antiplatelet action of xanthohumol (XN), the principal flavonoid in hop cones, was investigated. XN significantly attenuated ADP-induced blood platelet aggregation (97.2 ± 35.7 AU for 6 µg/ml of XN vs. 120.4 ± 30.1 AU for 0.17% dimethyl sulfoxide (DMSO), p < 0.001) and significantly reduced the expression of fibrinogen receptor (activated form of GPIIbIIIa) on platelets' surface (47.6 ± 15.8 for 1.5 µg/ml XN, 44.6 ± 17.3% for 3 µg/ml XN vs. 54.5 ± 19.2% for control or 43.3 ± 18.4% for 6 µg/ml XN vs. 49.7 ± 19.4% for 0.17% DMSO, p < 0.05 or less). These findings suggest that the phenolic compounds originating from hops (XN) have a novel role as antiplatelet agents and can likely be used as dietary supplements in prophylactic approaches.

Pharmacokinetics of prenylated hop phenols in women following oral administration of a standardized extract of hops.

SCOPE: Women seeking alternatives to hormone-replacement therapy for menopausal symptoms often try botanical dietary supplements containing extracts of hops (Humulus lupulus L.). Hops contain 8-prenylnaringenin (8-PN), a potent phytoestrogen, the related flavanones 6-prenylnaringenin and isoxanthohumol (IX), and the prenylated chalcone xanthohumol (XN). METHODS AND RESULTS: After chemically and biologically standardizing an extract of spent hops to these marker compounds, an escalating dose study was carried out in menopausal women to evaluate safety and pharmacokinetics. 8-PN, 6-prenylnaringenin, IX, and XN, sex hormones, and prothrombin time were determined in blood samples and/or 24 h urine samples. There was no effect on sex hormones or blood clotting. The maximum serum concentrations of the prenylated phenols were dose-dependent and were reached from 2 to 7 h, indicating slow absorption. The marker compounds formed glucuronides that were found in serum and urine. Secondary peaks at 5 h in the serum concentration-time curves indicated enterohepatic recirculation. The serum concentration-time curves indicated demethylation of IX to form 8-PN and cyclization of XN to IX. Slow absorption and enterohepatic recirculation contributed to half-lives exceeding 20 h. CONCLUSION: This human study indicated long half-lives of the estrogenic and proestrogenic prenylated phenols in hops but no acute toxicity.

Assessment of the anticancer compounds Se-methylselenocysteine and glucosinolates in Se-biofortified broccoli (Brassica oleracea L. var. italica) sprouts and florets.

Broccoli (Brassica oleracea L. var. italica) is a rich source of chemopreventive compounds. Here, we evaluated and compared the effect of selenium (Se) treatment on the accumulation of anticancer compounds Se-methylselenocysteine (SeMSCys) and glucosinolates in broccoli sprouts and florets. Total Se and SeMSCys content in sprouts increased concomitantly with increasing Se doses. Selenate was superior to selenite in inducing total Se accumulation, but selenite is equally effective as selenate in promoting SeMSCys synthesis in sprouts. Increasing sulfur doses reduced total Se and SeMSCys content in sprouts treated with selenate, but not in those with selenite. Examination of five broccoli cultivars reveals that sprouts generally have better fractional ability than florets to convert inorganic Se into SeMSCys. Distinctive glucosinolate profiles between sprouts and florets were observed, and sprouts contained approximately 6-fold more glucoraphanin than florets. In contrast to florets, glucosinolate content was not affected by Se treatment in sprouts. Thus, Se-enriched broccoli sprouts are excellent for simultaneous accumulation of chemopreventive compounds SeMSCys and glucoraphanin.

Florets of sunflower (Helianthus annuus L.): potential new sources of dietary fiber and phenolic acids.

Ray florets (Rf) and disc florets (Df) are agricultural byproducts of sunflower seeds. Their nutrition-related compounds were determined. The dietary fiber contents in Rf and Df were 42.90 mg/100 g and 58.97 mg/100 g. In both florets, palmitic, linoleic, and linolenic acids were identified as the three most abundant fatty acids, and the saturated ones constitute approximately two-thirds (w/w) of the total fatty acids. Lysine was the limiting amino acid in both florets by World Health Organization standards. Sixteen phenolic compounds, nine free and eight bound, mainly depsides, were identified in florets by RP-HPLC-DAD/ESI-TOF-MS. The free and bound phenolic compounds in Df were higher than in Rf. 1,5-di-O-caffeoylquinic acid was the predominant free phenolic compound in both florets. The present study revealed that the florets of sunflower are rich sources of dietary fiber, Fe, and phenols.