Mycoestrogens are xenoestrogens produced by fungi. They are sometimes referred to as mycotoxins.[1] Among important mycoestrogens are zearalenone, zearalenol and zearalanol.[2] Although all of these can be produced by various Fusarium species,[3][4] zearalenol and zearalanol may also be produced endogenously in ruminants that have ingested zearalenone.[5][6] Alpha-zearalanol is also produced semisynthetically, for veterinary use; such use is prohibited in the European Union.[7]

Mechanism of action

Mycoestrogens act as agonists of the estrogen receptors, ERα and ERβ.

Affinities of estrogen receptor ligands for the ERα and ERβ
Ligand Other names Relative binding affinities (RBA, %)a Absolute binding affinities (Ki, nM)a Action
ERα ERβ ERα ERβ
Estradiol E2; 17β-Estradiol 100 100 0.115 (0.04–0.24) 0.15 (0.10–2.08) Estrogen
Estrone E1; 17-Ketoestradiol 16.39 (0.7–60) 6.5 (1.36–52) 0.445 (0.3–1.01) 1.75 (0.35–9.24) Estrogen
Estriol E3; 16α-OH-17β-E2 12.65 (4.03–56) 26 (14.0–44.6) 0.45 (0.35–1.4) 0.7 (0.63–0.7) Estrogen
Estetrol E4; 15α,16α-Di-OH-17β-E2 4.0 3.0 4.9 19 Estrogen
Alfatradiol 17α-Estradiol 20.5 (7–80.1) 8.195 (2–42) 0.2–0.52 0.43–1.2 Metabolite
16-Epiestriol 16β-Hydroxy-17β-estradiol 7.795 (4.94–63) 50 ? ? Metabolite
17-Epiestriol 16α-Hydroxy-17α-estradiol 55.45 (29–103) 79–80 ? ? Metabolite
16,17-Epiestriol 16β-Hydroxy-17α-estradiol 1.0 13 ? ? Metabolite
2-Hydroxyestradiol 2-OH-E2 22 (7–81) 11–35 2.5 1.3 Metabolite
2-Methoxyestradiol 2-MeO-E2 0.0027–2.0 1.0 ? ? Metabolite
4-Hydroxyestradiol 4-OH-E2 13 (8–70) 7–56 1.0 1.9 Metabolite
4-Methoxyestradiol 4-MeO-E2 2.0 1.0 ? ? Metabolite
2-Hydroxyestrone 2-OH-E1 2.0–4.0 0.2–0.4 ? ? Metabolite
2-Methoxyestrone 2-MeO-E1 <0.001–<1 <1 ? ? Metabolite
4-Hydroxyestrone 4-OH-E1 1.0–2.0 1.0 ? ? Metabolite
4-Methoxyestrone 4-MeO-E1 <1 <1 ? ? Metabolite
16α-Hydroxyestrone 16α-OH-E1; 17-Ketoestriol 2.0–6.5 35 ? ? Metabolite
2-Hydroxyestriol 2-OH-E3 2.0 1.0 ? ? Metabolite
4-Methoxyestriol 4-MeO-E3 1.0 1.0 ? ? Metabolite
Estradiol sulfate E2S; Estradiol 3-sulfate <1 <1 ? ? Metabolite
Estradiol disulfate Estradiol 3,17β-disulfate 0.0004 ? ? ? Metabolite
Estradiol 3-glucuronide E2-3G 0.0079 ? ? ? Metabolite
Estradiol 17β-glucuronide E2-17G 0.0015 ? ? ? Metabolite
Estradiol 3-gluc. 17β-sulfate E2-3G-17S 0.0001 ? ? ? Metabolite
Estrone sulfate E1S; Estrone 3-sulfate <1 <1 >10 >10 Metabolite
Estradiol benzoate EB; Estradiol 3-benzoate 10 ? ? ? Estrogen
Estradiol 17β-benzoate E2-17B 11.3 32.6 ? ? Estrogen
Estrone methyl ether Estrone 3-methyl ether 0.145 ? ? ? Estrogen
ent-Estradiol 1-Estradiol 1.31–12.34 9.44–80.07 ? ? Estrogen
Equilin 7-Dehydroestrone 13 (4.0–28.9) 13.0–49 0.79 0.36 Estrogen
Equilenin 6,8-Didehydroestrone 2.0–15 7.0–20 0.64 0.62 Estrogen
17β-Dihydroequilin 7-Dehydro-17β-estradiol 7.9–113 7.9–108 0.09 0.17 Estrogen
17α-Dihydroequilin 7-Dehydro-17α-estradiol 18.6 (18–41) 14–32 0.24 0.57 Estrogen
17β-Dihydroequilenin 6,8-Didehydro-17β-estradiol 35–68 90–100 0.15 0.20 Estrogen
17α-Dihydroequilenin 6,8-Didehydro-17α-estradiol 20 49 0.50 0.37 Estrogen
Δ8-Estradiol 8,9-Dehydro-17β-estradiol 68 72 0.15 0.25 Estrogen
Δ8-Estrone 8,9-Dehydroestrone 19 32 0.52 0.57 Estrogen
Ethinylestradiol EE; 17α-Ethynyl-17β-E2 120.9 (68.8–480) 44.4 (2.0–144) 0.02–0.05 0.29–0.81 Estrogen
Mestranol EE 3-methyl ether ? 2.5 ? ? Estrogen
Moxestrol RU-2858; 11β-Methoxy-EE 35–43 5–20 0.5 2.6 Estrogen
Methylestradiol 17α-Methyl-17β-estradiol 70 44 ? ? Estrogen
Diethylstilbestrol DES; Stilbestrol 129.5 (89.1–468) 219.63 (61.2–295) 0.04 0.05 Estrogen
Hexestrol Dihydrodiethylstilbestrol 153.6 (31–302) 60–234 0.06 0.06 Estrogen
Dienestrol Dehydrostilbestrol 37 (20.4–223) 56–404 0.05 0.03 Estrogen
Benzestrol (B2) – 114 ? ? ? Estrogen
Chlorotrianisene TACE 1.74 ? 15.30 ? Estrogen
Triphenylethylene TPE 0.074 ? ? ? Estrogen
Triphenylbromoethylene TPBE 2.69 ? ? ? Estrogen
Tamoxifen ICI-46,474 3 (0.1–47) 3.33 (0.28–6) 3.4–9.69 2.5 SERM
Afimoxifene 4-Hydroxytamoxifen; 4-OHT 100.1 (1.7–257) 10 (0.98–339) 2.3 (0.1–3.61) 0.04–4.8 SERM
Toremifene 4-Chlorotamoxifen; 4-CT ? ? 7.14–20.3 15.4 SERM
Clomifene MRL-41 25 (19.2–37.2) 12 0.9 1.2 SERM
Cyclofenil F-6066; Sexovid 151–152 243 ? ? SERM
Nafoxidine U-11,000A 30.9–44 16 0.3 0.8 SERM
Raloxifene – 41.2 (7.8–69) 5.34 (0.54–16) 0.188–0.52 20.2 SERM
Arzoxifene LY-353,381 ? ? 0.179 ? SERM
Lasofoxifene CP-336,156 10.2–166 19.0 0.229 ? SERM
Ormeloxifene Centchroman ? ? 0.313 ? SERM
Levormeloxifene 6720-CDRI; NNC-460,020 1.55 1.88 ? ? SERM
Ospemifene Deaminohydroxytoremifene 0.82–2.63 0.59–1.22 ? ? SERM
Bazedoxifene – ? ? 0.053 ? SERM
Etacstil GW-5638 4.30 11.5 ? ? SERM
ICI-164,384 – 63.5 (3.70–97.7) 166 0.2 0.08 Antiestrogen
Fulvestrant ICI-182,780 43.5 (9.4–325) 21.65 (2.05–40.5) 0.42 1.3 Antiestrogen
Propylpyrazoletriol PPT 49 (10.0–89.1) 0.12 0.40 92.8 ERα agonist
16α-LE2 16α-Lactone-17β-estradiol 14.6–57 0.089 0.27 131 ERα agonist
16α-Iodo-E2 16α-Iodo-17β-estradiol 30.2 2.30 ? ? ERα agonist
Methylpiperidinopyrazole MPP 11 0.05 ? ? ERα antagonist
Diarylpropionitrile DPN 0.12–0.25 6.6–18 32.4 1.7 ERβ agonist
8β-VE2 8β-Vinyl-17β-estradiol 0.35 22.0–83 12.9 0.50 ERβ agonist
Prinaberel ERB-041; WAY-202,041 0.27 67–72 ? ? ERβ agonist
ERB-196 WAY-202,196 ? 180 ? ? ERβ agonist
Erteberel SERBA-1; LY-500,307 ? ? 2.68 0.19 ERβ agonist
SERBA-2 – ? ? 14.5 1.54 ERβ agonist
Coumestrol – 9.225 (0.0117–94) 64.125 (0.41–185) 0.14–80.0 0.07–27.0 Xenoestrogen
Genistein – 0.445 (0.0012–16) 33.42 (0.86–87) 2.6–126 0.3–12.8 Xenoestrogen
Equol – 0.2–0.287 0.85 (0.10–2.85) ? ? Xenoestrogen
Daidzein – 0.07 (0.0018–9.3) 0.7865 (0.04–17.1) 2.0 85.3 Xenoestrogen
Biochanin A – 0.04 (0.022–0.15) 0.6225 (0.010–1.2) 174 8.9 Xenoestrogen
Kaempferol – 0.07 (0.029–0.10) 2.2 (0.002–3.00) ? ? Xenoestrogen
Naringenin – 0.0054 (<0.001–0.01) 0.15 (0.11–0.33) ? ? Xenoestrogen
8-Prenylnaringenin 8-PN 4.4 ? ? ? Xenoestrogen
Quercetin – <0.001–0.01 0.002–0.040 ? ? Xenoestrogen
Ipriflavone – <0.01 <0.01 ? ? Xenoestrogen
Miroestrol – 0.39 ? ? ? Xenoestrogen
Deoxymiroestrol – 2.0 ? ? ? Xenoestrogen
β-Sitosterol – <0.001–0.0875 <0.001–0.016 ? ? Xenoestrogen
Resveratrol – <0.001–0.0032 ? ? ? Xenoestrogen
α-Zearalenol – 48 (13–52.5) ? ? ? Xenoestrogen
β-Zearalenol – 0.6 (0.032–13) ? ? ? Xenoestrogen
Zeranol α-Zearalanol 48–111 ? ? ? Xenoestrogen
Taleranol β-Zearalanol 16 (13–17.8) 14 0.8 0.9 Xenoestrogen
Zearalenone ZEN 7.68 (2.04–28) 9.45 (2.43–31.5) ? ? Xenoestrogen
Zearalanone ZAN 0.51 ? ? ? Xenoestrogen
Bisphenol A BPA 0.0315 (0.008–1.0) 0.135 (0.002–4.23) 195 35 Xenoestrogen
Endosulfan EDS <0.001–<0.01 <0.01 ? ? Xenoestrogen
Kepone Chlordecone 0.0069–0.2 ? ? ? Xenoestrogen
o,p'-DDT – 0.0073–0.4 ? ? ? Xenoestrogen
p,p'-DDT – 0.03 ? ? ? Xenoestrogen
Methoxychlor p,p'-Dimethoxy-DDT 0.01 (<0.001–0.02) 0.01–0.13 ? ? Xenoestrogen
HPTE Hydroxychlor; p,p'-OH-DDT 1.2–1.7 ? ? ? Xenoestrogen
Testosterone T; 4-Androstenolone <0.0001–<0.01 <0.002–0.040 >5000 >5000 Androgen
Dihydrotestosterone DHT; 5α-Androstanolone 0.01 (<0.001–0.05) 0.0059–0.17 221–>5000 73–1688 Androgen
Nandrolone 19-Nortestosterone; 19-NT 0.01 0.23 765 53 Androgen
Dehydroepiandrosterone DHEA; Prasterone 0.038 (<0.001–0.04) 0.019–0.07 245–1053 163–515 Androgen
5-Androstenediol A5; Androstenediol 6 17 3.6 0.9 Androgen
4-Androstenediol – 0.5 0.6 23 19 Androgen
4-Androstenedione A4; Androstenedione <0.01 <0.01 >10000 >10000 Androgen
3α-Androstanediol 3α-Adiol 0.07 0.3 260 48 Androgen
3β-Androstanediol 3β-Adiol 3 7 6 2 Androgen
Androstanedione 5α-Androstanedione <0.01 <0.01 >10000 >10000 Androgen
Etiocholanedione 5β-Androstanedione <0.01 <0.01 >10000 >10000 Androgen
Methyltestosterone 17α-Methyltestosterone <0.0001 ? ? ? Androgen
Ethinyl-3α-androstanediol 17α-Ethynyl-3α-adiol 4.0 <0.07 ? ? Estrogen
Ethinyl-3β-androstanediol 17α-Ethynyl-3β-adiol 50 5.6 ? ? Estrogen
Progesterone P4; 4-Pregnenedione <0.001–0.6 <0.001–0.010 ? ? Progestogen
Norethisterone NET; 17α-Ethynyl-19-NT 0.085 (0.0015–<0.1) 0.1 (0.01–0.3) 152 1084 Progestogen
Norethynodrel 5(10)-Norethisterone 0.5 (0.3–0.7) <0.1–0.22 14 53 Progestogen
Tibolone 7α-Methylnorethynodrel 0.5 (0.45–2.0) 0.2–0.076 ? ? Progestogen
Δ4-Tibolone 7α-Methylnorethisterone 0.069–<0.1 0.027–<0.1 ? ? Progestogen
3α-Hydroxytibolone – 2.5 (1.06–5.0) 0.6–0.8 ? ? Progestogen
3β-Hydroxytibolone – 1.6 (0.75–1.9) 0.070–0.1 ? ? Progestogen
Footnotes: a = (1) Binding affinity values are of the format "median (range)" (# (#–#)), "range" (#–#), or "value" (#) depending on the values available. The full sets of values within the ranges can be found in the Wiki code. (2) Binding affinities were determined via displacement studies in a variety of in-vitro systems with labeled estradiol and human ERα and ERβ proteins (except the ERβ values from Kuiper et al. (1997), which are rat ERβ). Sources: See template page.

Sources

Mycoestrogens are produced by various strains of fungi, many of which fall under the genus Fusarium. Fusarium fungi are filamentous fungi that are found in the soil and are associated with plants and some crops, especially cereals.[8] Zearalenone is mainly produced by F. graminearum and F. culmorum strains, which inhabit different areas depending on temperature and humidity. F. graminearum prefers to inhabit warmer and more humid locations such as Eastern Europe, Northern America, Eastern Australia, and Southern China in comparison to F. colmorum which is found in colder Western Europe.[9]

Health effects

Mycoestrogens mimic natural estrogen in the body by acting as estrogen receptor (ER) ligands.[8] Mycoestrogens have been identified as endocrine disruptors due to their high binding affinity for ERα and ERβ, exceeding that of well known antagonists such as bisphenol A and DDT.[10] Studies have been performed that strongly suggest a relationship between detectable levels of mycoestrogen and growth and pubertal development. More than one study has shown that detectable levels of zearalenone and its metabolite alpha-zearalanol in girls are associated with significantly shorter heights at menarche.[1][10] Other reports have documented premature onset of puberty in girls. Estrogen are known to cause decreased body weight in model animals, and the same effect has been seen in rats exposed to zearalenone.[11] Interactions of ZEN and its metabolite with human androgen receptors (hAR) have also been documented.[9]

Metabolism

Zearalenone has two major phase I metabolites: α-zearalenol and β-zearalenol.[11][9] When exposed orally ZEN is absorbed by the intestinal lining and metabolized there as well as in the liver.[11] Research into the metabolism of ZEN has been difficult because of the significant difference in biotransformation between species making comparison challenging.

Phase I

The first transformation of metabolism of ZEN will reduce the ketone group to an alcohol via aliphatic hydroxylation and result in the formation of the two zearalenol metabolites. This process is catalyzed by 3 α- and 3 β-hydroxy steroid dehydrogenase (HSD). CYP450 enzymes will then catalyze aromatic hydroxylation at the 13 or 15 position resulting in 13- or 15- catechols. Steric hindrance of at the 13 position is suspected to be the reason that in humans and rats there is more of the 15-catechol present. The catechols are the processed into mono-ethyl esters by catechol-o-methyl transferase (COMT) and S-adenosyl methionine (SAM). After this transformation they may be metabolized further to quinones which can cause the formation of reactive oxygen species (ROS) and cause covalent modification of DNA.[12]

Phase II

In phase-II metabolizing includes glucuronidation and sulfation of the mycoestrogen compound. Glucuronidation is the major phase II metabolic pathway. The transferase UGT (5'-diphosphate glucuronosyltransferase) adds a glucuronic acid group sourced from uridine 5'-diphosphate glucuronic acid (UDPGA).[12]

Excretion

Mycoestrogens and their metabolites are largely excreted in urine in humans and in feces in other animal systems.[12]

In food

Mycoestrogens are commonly found in stored grain. They can come from fungi growing on the grain as it grows, or after harvest during storage. Mycoestrogens can be found in silage.[13] Some estimates state that 25% of global cereal production and 20% of global plant production may be at some point contaminated by mycotoxins of which mycoestrogens, especially those from fusarium strains, may make up a significant portion.[9] Among mycoestrogens that contaminate plants are ZEN and its phase I metabolites. The limit for ZEN in unprocessed cereals, milling products, and cereal foodstuffs is 20-400 μg/kg (depending on the product in question).[9]

Types

References

  1. ^ a b Rivera-Núñez Z, Barrett ES, Szamreta EA, Shapses SA, Qin B, Lin Y, Zarbl H, Buckley B, Bandera EV (March 2019). "Urinary mycoestrogens and age and height at menarche in New Jersey girls". Environmental Health. 18 (1): 24. doi:10.1186/s12940-019-0464-8. PMC 6431018. PMID 30902092.
  2. ^ Fink-Gremmels, J.; Malekinejad, H. (October 2007). "Clinical effects and biochemical mechanisms associated with exposure to the mycoestrogen zearalenone". Animal Feed Science and Technology. 137 (3–4): 326–341. doi:10.1016/j.anifeedsci.2007.06.008.
  3. ^ Richardson, Kurt E.; Hagler, Winston M.; Mirocha, Chester J. (September 1985). "Production of zearalenone, .alpha.- and .beta.-zearalenol, and .alpha.- and .beta.-zearalanol by Fusarium spp. in rice culture". Journal of Agricultural and Food Chemistry. 33 (5): 862–866. doi:10.1021/jf00065a024.
  4. ^ Hsieh HY, Shyu CL, Liao CW, Lee RJ, Lee MR, Vickroy TW, Chou CC (April 2012). "Liquid chromatography incorporating ultraviolet and electrochemical analyses for dual detection of zeranol and zearalenone metabolites in mouldy grains". Journal of the Science of Food and Agriculture. 92 (6): 1230–7. doi:10.1002/jsfa.4687. PMID 22012692.
  5. ^ Miles CO, Erasmuson AF, Wilkins AL, Towers NR, Smith BL, Garthwaite I, Scahill BG, Hansen RP (October 1996). "Ovine metabolism of zearalenone to α-zearalanol (zeranol)". Journal of Agricultural and Food Chemistry. 44 (10): 3244–50. doi:10.1021/jf9601325.
  6. ^ Kennedy DG, Hewitt SA, McEvoy JD, Currie JW, Cannavan A, Blanchflower WJ, Elliot CT (1998). "Zeranol is formed from Fusarium spp. toxins in cattle in vivo". Food Additives and Contaminants. 15 (4): 393–400. doi:10.1080/02652039809374658. PMID 9764208.
  7. ^ Thevis M, Fusshöller G, Schänzer W (2011). "Zeranol: doping offence or mycotoxin? A case-related study". Drug Testing and Analysis. 3 (11–12): 777–83. doi:10.1002/dta.352. PMID 22095651.
  8. ^ a b Ding X, Lichti K, Staudinger JL (June 2006). "The mycoestrogen zearalenone induces CYP3A through activation of the pregnane X receptor". Toxicological Sciences. 91 (2): 448–55. doi:10.1093/toxsci/kfj163. PMC 2981864. PMID 16547076.
  9. ^ a b c d e Bryła M, Waśkiewicz A, Ksieniewicz-Woźniak E, Szymczyk K, Jędrzejczak R (April 2018). "Fusarium Mycotoxins in Cereals and Their Products-Metabolism, Occurrence, and Toxicity: An Updated Review". Molecules. 23 (4). doi:10.3390/molecules23040963. PMC 6017960. PMID 29677133.
  10. ^ a b Bandera EV, Chandran U, Buckley B, Lin Y, Isukapalli S, Marshall I, King M, Zarbl H (November 2011). "Urinary mycoestrogens, body size and breast development in New Jersey girls". The Science of the Total Environment. 409 (24): 5221–7. Bibcode:2011ScTEn.409.5221B. doi:10.1016/j.scitotenv.2011.09.029. PMC 3312601. PMID 21975003.
  11. ^ a b c Hueza IM, Raspantini PC, Raspantini LE, Latorre AO, Górniak SL (March 2014). "Zearalenone, an estrogenic mycotoxin, is an immunotoxic compound". Toxins. 6 (3): 1080–95. doi:10.3390/toxins6031080. PMC 3968378. PMID 24632555.
  12. ^ a b c Mukherjee D, Royce SG, Alexander JA, Buckley B, Isukapalli SS, Bandera EV, Zarbl H, Georgopoulos PG (2014-12-04). "Physiologically-based toxicokinetic modeling of zearalenone and its metabolites: application to the Jersey girl study". PLOS ONE. 9 (12): e113632. Bibcode:2014PLoSO...9k3632M. doi:10.1371/journal.pone.0113632. PMC 4256163. PMID 25474635.
  13. ^ González Pereyra ML, Alonso VA, Sager R, Morlaco MB, Magnoli CE, Astoreca AL, Rosa CA, Chiacchiera SM, Dalcero AM, Cavaglieri LR (April 2008). "Fungi and selected mycotoxins from pre- and postfermented corn silage". Journal of Applied Microbiology. 104 (4): 1034–41. doi:10.1111/j.1365-2672.2007.03634.x. PMID 18005347.
  14. ^ Marin S, Ramos AJ, Cano-Sancho G, Sanchis V (October 2013). "Mycotoxins: occurrence, toxicology, and exposure assessment". Food and Chemical Toxicology. 60: 218–37. doi:10.1016/j.fct.2013.07.047. PMID 23907020.
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