Sublethal Toxicity of Acid Black-1 (AB-1, CI: 20470) on Antioxidative and Detoxification Enzyme Responses in Labeo...

This investigation evaluated the impact of different sublethal concentrations of Acid Black-1 (AB-1, CI: 20470) on the activity of key enzymes involved in the antioxidant defense system. Glutathione reductase (GR), glutathione peroxidase (GPx), catalase (CAT), superoxide dismutase (SOD), and glutathione S-transferase (GST) activities were assessed in the liver, kidney, gill, muscle, and brain of Labeo rohita. The study involved a 150-day subchronic exposure period followed by a 90-day recovery phase. Enzyme activities in all tested tissues exhibited dose- and duration-dependent changes during both exposure and recovery. Notably, GR, GPx, and SOD activities were significantly altered in all the tissues, with the most pronounced changes observed in the muscle for a majority of the enzymes. A consistent and marked decline in SOD activity throughout the study strongly suggests that repeated exposure to even minute concentrations of AB-1 induced significant and prolonged oxidative stress. Further, the molecular docking studies indicated that AB-1 interacted with different enzymes via either the active site or the binding site, thereby affecting the enzyme activity. Our findings indicate that AB-1, even at the lowest concentration, elicited clear toxic effects in L. rohita. Based on these subchronic findings, SOD is proposed as a potential biomarker enzyme for AB-1 toxicity in this fish species.