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Activation of pro-estrogens from hops by intestinal bacteria

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)

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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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