Curcumin (diferuloylmethane) is a dietary polyphenol derived from the rhizomes of turmeric (Curcuma longa). For a long time, curcumin has been applied as an anti-inflammatory, 1) anti-oxidative, 2-4) and anti-carcinogenic 5) compound. The multiple therapeutic effects of curcumin result from its ability to modulate enzyme activities and gene expression. For example, curcumin has been shown to down-regulate the activities of several transcription factors, including NF-kappa B, AP-1, and Egr-1, as well as growth factor receptors such as EGFR and HER2. 6) Curcumin also inhibits the activities of COX2, LOX, iNOS, MMP-9, c-Jun N-terminal kinase, protein tyrosine kinases, and protein serine/threonine kinases. 6) Curcumin has been shown to repress expression of oncogenes such as c-fos, c-jun and c-myc, and suppress proliferation of tumour cells. [7][8][9] Finally, recent studies have demonstrated that curcumin can inhibit p300/CBP histone acetyltransferase activity both in vivo and in vitro. 10,11) p300/CBP transfers the acetyl group from an acetyl-CoA to conserved lysine residues in the histones, consequently, leading to transcription activity.12) Therefore, curcumin may modulate gene expression through inhibition of p300/CBP activities.Although the effects of curcumin on enzyme activities and gene expression have been studied in detail, only a few reports described its toxicity to embryos. The studies using rats as animal models have shown that orally administered curcumin has no toxic effects on fertility or pregnancy in the fed rats, and no malformations were observed in their offspring.13) In this report, we used zebrafish (Danio rerio) as model organisms to investigate the developmental toxicity of curcumin. Advantages of using zebrafish as model organisms include their small size (2-4 cm long), ease of breeding in the laboratory, light-induced fertilization, and sensitivity to environmental changes. Our results indicated that, unlike in rats, curcumin had embryotoxic and teratogenic effects on zebrafish embryos in a mM region.
MATERIALS AND METHODS
Collecting Fertilized Zebrafish EggsAdult zebrafish purchased from a local fish store were maintained in a laboratory under 28Ϯ1°C and a 14 h day/10 h night photoperiod.Fertilized eggs were collected within 30 min after natural mating, washed with sterile water, and placed in petri dishes.Curcumin Treatment and Embryos Observances Curcumin was purchased from Sigma Chemical (St. Louis, MO, U.S.A.), and dissolved in dimethyl sulfoxide (DMSO) to make a 25 mM stock solution. For embryo exposures, fertilized eggs were placed in 6-well petri dishes with ten embryos per well in 10 ml sterile water. Next, 30 ml of seriously diluted curcumin stock solutions was added to get final concentrations of 5, 7.5, 10, 12.5, and 15 mM. Thirty embryos were used for each of four replicates. The embryotoxic and teratogenic effects of resveratrol, quercetin, and rutin were also investigated in this study. Resveratrol, quercetin, and rutin were all purchased from Sigma Chemical (St. Louis, MO...
