The teratogenic effects of the ethanolic extract of green tea (Camellia sinensis) in the larval stage of zebrafish (Danio rerio)

The most abundant compounds present in the ethanolic extract of green tea (EGT) are epigallocatecin gallate (EGCG), quercetin and kaempferol. EGCG is a competitive inhibitor of dihydrofolate reductase, an enzyme involved in folate-mediated one-carbon metabolism. EGCG, quercetin and kaempferol are known to inhibit tyrosinase, the enzyme that catalyzes the synthesis of melanin in melanocytes. The purpose of this study was to determine the effect of EGT on cardiac deformities, body length and hypopigmentation in zebrafish larvae. The embryos were divided into four experimental groups, including embryos treated with EGT 125, 250 or 500 ppm and a control group. Zebrafish embryos were exposed to EGT at 2, 24 and 48 hours postfertilization. The observations were performed on larvae 72 hours post-fertilization, and photos were taken using OPTILAB software. The results showed a significant reduction in heart rate (p = 0.003) and cardiac morphological abnormalities (p = 0.000), in addition to reduced body length (p = 0.000) and hypopigmentation (p = 0.000). In conclusion, exposure of embryos to EGT caused cardiac malformation, reduced body length and hypopigmentation in zebrafish larvae. This research can be used in determining the safety of green tea consumption during the pre-conception or early pregnancy periods.