LC50 Determination and Phenotypic Analysis of Three C6-C1 and C6-C3 Bio-phenols Using Zebrafish (Danio rerio) Model

Due to the great natural products importance as our more highlighted toolbox to fight against several pathologies, we decide to evaluate the toxicity and reproductive effect of three popular phenols, carvacrol, thymol and eugenol; commonly useful them in pharmacology, cosmetic and food industry. Zebrafish (Danio rerio) model was used to evaluated LC50 and phenotypic changes in embryo stage. The LC50 was calculated for eugenol, 18.7 mg/L; thymol, 7.7 mg/L and carvacrol 5.0 mg/L. Obtained LC50 values were according with early reports for eugenol, 13.2 mg/L. Afterwards phenotypic analysis was carried out to different concentrations and registered to 48, 72 and 96 hpf (hours post fecundation). For the 48 hpf analysis, eugenol showed a normal growth until 2.337 mg/L where as we could observe, a soft tail curvature, body depigmentation and non-normal yolk sac growth. To the 72 hpf embryos exposed to eugenol showed normal growth to the first concentrations, but its died to 2.337 mg/L and 1.168 mg/L. In the carvacrol molecule, analysis image showed cardiac edema and adverse effects in jaw growth. Embryos exposed to thymol does not showed any reproductive effects.