RESUMO
In recent years, numerous research outcomes were established on various naturally occurring compounds that have been shown to have beneficial antioxidant and other biological activities. Antioxidant defence mechanism plays a vital role in combating various diseases mainly due to oxidative stress. However, various models have been utilized to identify their bioactivities using these compounds (quercetin, gallic acid and curcumin). Their toxicity level also has to be explored to determine the threshold levels on the usage of these compounds. In this study, we investigated the lethal concentration of these compounds and abnormalities, biochemical and morphological changes in zebrafish embryo (Danio rerio). Toxicity level was evaluated by calculating the LD50 on the embryonic stages at 24, 48 and 72 h. Antioxidant parameters such as superoxide dismutase (SOD), catalase (CAT), glutathione (GSH) and biological assays such as lipid peroxidation, protein estimation were performed. Microscopic evaluations were also observed to find out morphological abnormalities. However, these naturally derived compounds are reported to have their protective and curative role in many health complications. From the above assays, we are studying the effect of the drugs in both biochemical and molecular way in the zebrafish model organism.