Toxicological evaluation and effective dose selection of eurycomanone, a quassinoid of Eurycoma longifolia plant in fishes

The study was undertaken to investigate the toxicity level and safe dosage of eurycomanone, a major compound of Eurycoma longifolia plant extract in catfish. For that, combined approaches like, genotoxicity studies, biochemical, molecular and histopathological analysis were followed. The 96 h LD50 of eurycomanone was found to be 391.716 μg/kg (0.3917 μg/g). The sub-acute toxicity levels of eurycomanone at concentrations, 0.274 μg/g (70% LD50; Ed1) and 0.137 μg/g (35% LD50; Ed2) were analysed to determine the safer dose for fish. Significant genotoxic effects (micronuclei and DNA damage) and elevation in biochemical parameters (AST, ALT and LDH) were detected in the Ed1 group than Ed2. Transcript levels of apoptotic genes were significantly more (P < 0.05) in Ed1 than Ed2 and control groups. The histopathological examination suggested that Ed2 caused severe damage to the liver cells of catfish. The above results collectively suggested that the 70% LD50 of eurycomanone was detrimental while 35% was safer for the catfish. This is the first report showing the toxicity levels of eurycomanone on fish. Furthermore, the safe dose could be effectively used to exploit the beneficial effects of this compound as used in higher animals.