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Table 1 Sample list of a subset of well-established obesogens with their partitioning coefficients, half-life, and molecular weight (g/mol). The octanol/water partitioning coefficient is measured using the log Kow value, which indicates the partitioning of a chemical between octanol and water. In these experiments, octanol is used to mimic fat and other hydrophobic components in biological systems. A partitioning coefficient level greater than 1 indicates low solubility in water

From: Mechanisms of action, chemical characteristics, and model systems of obesogens

Obesogen Source Obesogensa Chemical Characteristics*
Partitioning (Log Kow) b Half-life (hours)c Size (g/mol)
Industrial Chemicals Bisphenol A (BPA) 3.32 5.3d [10, 11] 228.291
Bisphenol A diglycidyl ether (BADGE) ~ 3.84 120e [12] 340.419
Bisphenol S (BPS) ~ 1.65 6.93 [13] 250.268
Firemaster 550 (FM550) 8.80–11.95f Unknown [14] 549.923
2,2′,4,4′-Tetrabromodiphenyl ether (BDE-47) 6.81 ± 0.08 [15] 664 daysg 485.795
3,3′,4,4′-Tetrachlorobiphenyl (PCB-77) 6.72 152186 [16] 291.980
Mono-(2-ethylhexyl) phthalate (MEHP) 4.92h 4.4–6.6i 278.348
bis(2-ethylhexyl) phthalate (DEHP) 7.60 5j 390.564
Biocides Dichlorodiphenyl-trichloroethane (DDT) 6.91 10.6k 354.476
Tributyltin (TBT) 3.90–4.90 [17] 23–30 days [18] 290.058
Triphenyltin (TPT) 4.19l 3 days 385.478
Pharmaceuticals Diethylstilbestrol (DES) 5.07 23 days [19] 268.350
Estradiol (Estrogen steroid Hormone) 4.01 3 days 272.388
Pollutant Dioxin 6.80 5–8 years 321.970
Smoking Nicotine 1.17 1–4m 162.236
  1. Sources
  2. *Values of partition coefficients and half-lives might differ from those in this table because of variations in the study such as the location the study was conducted, type of tissue, biphasic pattern, initial dosage, temperature, salinity and pH.
  3. aThe obesogens discussed are well-established obesogens that have been used in various studies.
  4. bAll values of log Kow were reported at 25°C and at a pH of 7 unless stated otherwise.
  5. cAll estimated half-life values reported were conducted on studies in human based models unless stated otherwise.
  6. dBPA data are not consistent with the current consensus that BPA exposures are both rapidly cleared and almost entirely related to food intake. Instead, it appears plausible that there is substantial nonfood exposure, accumulation in body compartments with long elimination times, or both [3].
  7. eBisphenol A diglycidyl ether based on Hydrolysis in Water.
  8. f2-ethyl-1-hexyl-2,3,4,5-tetrabromobenzoate (TBB) and bis (2-ethylhexyl) tetrabromophthalate (TBPH) are the two major additive Brominated flame retardants (BFRs) in Firemaster 550. [16].
  9. gTetrabromodiphenyl ether (BDE-47) has two phases of elimination. The first phase of elimination is where the majority of the BDE-47 is eliminated from the body (67%), and the remaining BDE-47 is eliminated during the terminal phase. Additionally, elimination, both whole-body and from individual tissues, is biphasic due to varying initial and terminal phase lengths in different tissues. Since BDE-47 is highly lipophilic its terminal phase was primarily dictated by adipose tissue and skin [21].
  10. hMEHP was estimated from n-octanol: water coefficient (Kow) by the algorithm from Poulin and Krishnan (1993). A log Kow of 4.92 was estimated based on the chemical structure for nonionized MEHP.
  11. iSingle administration of MEHP in a rat (0.4 g/kg) resulted in plasma concentrations of 84.1 +/− 14.9 micrograms/ml 3 h after dosing; the half-life of MEHP was 5.5 +/− 1.1 h. [22].
  12. jAfter an absorption and distribution phase of 4 to 8 h, half-life times of excretion in the first elimination phase were approximately 2 h; Half-life times in the second phase—beginning 14 to 18 h post dose—were 5 h for MEHP [23].
  13. kFemale rats were dosed orally with (14) C-ring-labeled p,p’-DDT during pregnancy or lactation. Average half-life was 10.6 h in tissues and in the fetus.
  14. lTriphentylin Chloride was used to find the log Kow.
  15. mNicotine’s half-life in the initial phase is reportedly about 2–3 min and the half-life in the terminal phase averages about 2 h.
  16. Note: All partitioning coefficient values > 1 indicate lipophilic properties (bold). Half-life with strong indication of biphasic pattern (bold). Non-asterisk and cited chemical characteristics were obtained from the U.S. National Library of Medicine Open Chemistry Database and the International Programme on Chemical Safety.