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

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

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

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

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

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?

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

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

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?

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

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

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

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

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

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!

Contact information  Posters: Possemiers et al. Bolca et al.  LabMET – Ghent University Coupure Links 653 B-9000 Gent +32/9/