Acute Toxicity of Epigallocatechin Gallate and C-Phycocyanin in Zebrafish (Danio rerio): Behavioral and Histopathological Studies

Epigallocatechin gallate and C-phycocyanin are natural food supplements, gaining a lot of popularity in biomedical researches. The lethal concentration 50 value for the zebrafish model was determined using a 96 h semi-static acute toxicity test. Zebrafish were transferred into a 1 l water tank starting with a minimal dose of 8 mg of epigallocatechin gallate and 1 g of C-phycocyanin, which further increased to the concentration of 30 mg for epigallocatechin gallate and 5 g for C-phycocyanin. Lethal concentration 50 of epigallocatechin gallate and C-phycocyanin was calculated to be 21.37 mg/l and 2.45 g/l respectively at 96 h in the zebrafish model. At high doses above 12 mg of epigallocatechin gallate and 1 g of C-phycocyanin, the test fish displayed various behavior responses like erratic and jerky swimming, attempts to jump out of the water, frequent surfacing and swallowing of air, normal skin color change, decreased opercular movement and finally leading to death. Histological observations showed hypertrophy, atrophy and vacuolar degeneration in the liver whereas tubular degeneration, glomerular hyper cellularity, dilation of Bowman's space, hemorrhage, and necrosis were observed in the kidneys exposed to the high doses of epigallocatechin gallate and C-phycocyanin treated fish. The gills of the test animals also expressed lamellar synechiae, hyperplasia, curling of lamellae, mucus secretion and shortening of the secondary lamella. The results demonstrated that doses above 30 mg/l and 5 g/l in the case of epigallocatechin gallate and C-phycocyanin respectively gave 100 % mortality and expressed organ-specific toxicity. Overall results revealed that exposure to high concentrations of epigallocatechin gallate and C-phycocyanin uninterruptedly may lead to severe alterations in the tissue of experimental animals.