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Activation of pro-estrogens from hops by intestinal bacteria

This study investigates the activation of isoxanthohumol (IX) to 8-prenylnaringenin (8-PN), a potent phytoestrogen derived from hops. The intestinal microbiota play a crucial role in this conversion, impacting individual responses to phytoestrogens. Despite low concentrations in beer, the metabolic transformation can lead to significant biological effects on health, particularly in menopausal women. Findings reveal substantial interindividual variability in the conversion efficiency, highlighting the influence of gut microbiota composition on phytoestrogen bioavailability and potential health benefits.

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Activation of pro-estrogens from hops by intestinal bacteria

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  1. Activation of pro-estrogens from hops by intestinal bacteria Production of the phytoestrogen 8-prenylnaringenin Sam Possemiers, Selin Bolca, Veerle Maervoet, Tom Van de Wiele, Arne Heyerick, Denis De Keukeleire & Willy Verstraete Laboratory of Microbial Ecology & Technology (LabMET) http://labmet.ugent.be

  2. Phytoestrogens (1) • “Plant constituents which structurally or functionally mimic the female estrogen 17β-estradiol”  Beneficial role in the prevention of osteoporosis, menopauzal complaints and cancers  Applications! 17β-estradiol

  3. genistein Secoisolariciresinol (SECO) Phytoestrogens (2) • 2 well known groups: • Isoflavones from soy: daidzein, genistein • Lignans from linseed, fruits, nuts…

  4. Phytoestrogens (3) • Common caracteristics: • Crucial activation by the intestinal microbiota • Daidzein  equol • SECO  enterodiol, enterolacton • Strong influence on biological activity! • BUT: interindividual differences!!! • E.g. only 1/3rd of population produces equol  Beneficial effects depend on microbial community composition

  5. Phytoestrogens from hop (1) • Humulus lupulus L. (Hop) >Cannabaceae (+ Cannabis sativa L.) • Mainly used in beer industry • But also source of the prenylflavonoid 8-prenylnaringenin (8-PN)  3rd group of phytoestrogens

  6. Phytoestrogens from hop (2) • Research topic: • Intestinal metabolism? • Cfr other phytoestrogens: intestinal activation? • Hop prenylflavonoids: • 8-prenylnaringenin (8-PN): very low concentrations • Isoxanthohumol (IX) and Xanthohumol (X): not estrogens but much higher concentrations.  Metabolism of 8-PN, IX and X?

  7. Isoxanthohumol acts as pro-estrogen (1) • IX can be activated into 8-PN!

  8. O H O H H O O H O Isoxanthohumol acts as pro-estrogen (2) Michael addition Microbial O-demethylation Xanthohumol (X) Isoxanthohumol (IX) Michael addition + 6-Prenylnaringenin Desmethyl-xanthohumol 8-Prenylnaringenin (8-PN)

  9. Isoxanthohumol acts as pro-estrogen (3) • IX can be activated into 8-PN! • Relevance: • 8-PN conc in beer are too low for biological effects • Activation of IX: much higher exposure to 8-PN! • BUT: interindividual differences  Interindividual differences?

  10. Interindividual differences in vitro (1) • Experiment with 51 fecal samples • Incubation immediately after defecation • BHI + fecal samples (5%) 25 mg/L IX • 37°C, anaerobic conditions • HPLC and LC/MS analysis • % high, moderate and slow 8-PN producers? Possemiers et al., Journal of Nutrition, July 2006

  11. Interindividual differences in vitro (2) 2/3!  Interindividual differences: 3 significant groups!

  12. Interindividual differences in vivo (1) In vivo evaluation of the bioavailability and biotransformation of hop prenylflavonoids • 5 day intervention study (5.5 mg IX/d) • 50 postmenopauzal women • urine collection: • Absorption prenylflavonoids • Detection and identification of metabolites • Fecal sample collection • In vitro IX into 8-PN conversion • Molecular fingerprinting of intestinal community

  13. In vivo (2): fecal samples  High (A), moderate (C) and slow (B) IX-converter

  14. In vivo (3): urine  High (A), moderate (C) and slow (B) 8-PN excretion  Good correlation between in vitro and in vivo!

  15. Conclusions • Intestinal transformation of hop flavonoids: • Interindividual differences • 1/3rd converted IX into hopein (8-PN) • Good correlation in vitro and in vivo • Intestinal bacteria are responsible for the conversion in vivo • IX acts as pro-estrogen in food and supplements • Up to 4 mg IX/L in beer and 5 mg/supplement • Possible health effects not negligible! • Exposure dependent on intestinal microbial community!

  16. Contact information • Posters: • Possemiers et al. • Bolca et al. • LabMET – Ghent University Coupure Links 653 B-9000 Gent sam.possemiers@ugent.be http://labMET.ugent.be/ +32/9/264.59.76

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