Cytotoxic and xenoestrogenic effects via biotransformation of trans-anethole on isolated rat hepatocytes and cultured MCF-7 human breast cancer cells.
The metabolism and action of trans-anethole (anethole) and the estrogen-like activity of the compound and its metabolites were studied in freshly isolated rat hepatocytes and cultured MCF-7 human breast cancer cells, respectively. The incubation of hepatocytes with anethole (0.25-2.0mM) caused a concentration- and time-dependent cell death accompanied by losses of cellular ATP and adenine nucleotide pools. Anethole at a weakly toxic level (0.5mM) was metabolized to 4-methoxycinnamic acid (4MCA), 4-hydroxy-1-propenylbenzene (4OHPB), and the monosulfate conjugate of 4OHPB; the levels of 4OHPB sulfate and 4MCA reached approximately 20 and 200 microM within 2 hr, respectively, whereas that of free unconjugated 4OHPB was less than approximately 0.5 microM. At a moderately toxic concentration (1.0mM), unconjugated 4OHPB reached approximately 10 microM, followed by abrupt loss of 3'-phosphoadenosine 5'-phosphosulphate (PAPS). Based on cell viability and adenine nucleotide levels, 4OHPB was more toxic than anethole and 4MCA. The addition of 2,6-dichloro-4-nitrophenol (50 microM), an inhibitor of sulfotransferase, enhanced the anethole-induced cytotoxicity associated with losses of ATP, PAPS, and 4OHPB sulfate, and symmetrically increased the unconjugated 4OHPB concentration. 4OHPB as well as diethylstilbestrol (DES) and bisphenol A (BPA), which are known xenoestrogenic compounds, competitively displaced 17beta-estradiol bound to the estrogen receptor alpha in a concentration-dependent manner; IC(50) values of these compounds were approximately 1 x 10(-5), 1 x 10(-8) and 5 x 10(-5)M, respectively. 4OHPB also caused a concentration (10(-8) to 10(-6)M)-dependent proliferation of MCF-7 cells, whereas neither anethole nor 4MCA (10(-9) to 10(-5)M) affected cell proliferation. However, at higher concentrations (>10(-4)M), 4OHPB rather than anethole and 4MCA was cytotoxic. These results suggest that the biotransformation of anethole induces a cytotoxic effect at higher concentrations in rat hepatocytes and an estrogenic effect at lower concentrations in MCF-7 cells based on the concentrations of the hydroxylated intermediate, 4OHPB.
Nakagawa
Yoshio
Y
Department of Toxicology, Tokyo Metropolitan Research Laboratory of Public Health, 3-24-1 Hyakunin-cho, Shinjuku-ku, Tokyo 169-0073, Japan. yoshio@tokyo-eiken.go.jp
Suzuki
Toshinari
T
D000081248:Allylbenzene Derivatives; D000818:Animals; D000840:Anisoles / Q000378:metabolism* / Q000494:pharmacology; D001667:Binding, Competitive; D001711:Biotransformation; D001943:Breast Neoplasms / Q000473:pathology; D002455:Cell Division / Q000187:drug effects; D002470:Cell Survival / Q000187:drug effects; D002478:Cells, Cultured; D002934:Cinnamates / Q000494:pharmacology; D004347:Drug Interactions; D047628:Estrogen Receptor alpha; D022781:Hepatocytes / Q000187:drug effects / Q000378:metabolism*; D006801:Humans; D008297:Male; D010424:Pentobarbital / Q000031:analogs & derivatives* / Q000494:pharmacology; D051381:Rats; D011916:Rats, Inbred F344; D011960:Receptors, Estrogen / Q000187:drug effects / Q000378:metabolism; D015238:Sulfotransferases / Q000037:antagonists & inhibitors; D014407:Tumor Cells, Cultured
D000081248:Allylbenzene Derivatives; D000840:Anisoles; D002934:Cinnamates; D047628:Estrogen Receptor alpha; D011960:Receptors, Estrogen; C063318:4-methoxycinnamic acid; C038819:4'-hydroxypentobarbitone; D015238:Sulfotransferases; D010424:Pentobarbital; C006578:anethole