Adverse effects of textile dyes on antioxidant enzymes and cholinesterase activities in Drosophila melanogaster (Oregon R+)

Abstract

The effluents from textile dyeing industry are causing water pollution and may transform into more toxic and carcinogenic chemical species by environmental conditions. Therefore systemic toxicity of textile dyes is major health concern. Hence, this study sought to examine the toxic effect of disperse textile dyes on important systemic enzymes in the larvae of wild type Drosophila melanogaster (Oregon R+). Drosophila larvae were fed with corn-sugar-yeast diets containing two disperse dyes, Disperse blue-124 and Disperse black-9 (1, 10 and 100 mg/mL) for 2 days (48 h) and subsequent the enzymatic estimations were carried out using larval homogenate. In silico molecular docking studies were also performed to analyze the binding interaction of these dyes with acetyl choline esterase enzyme. Disperse black 9 shows more strong binding by occupying a groove and forming one hydrogen bond with Tyr465 of acetyl choline esterase enzyme while Disperse blue-124 shows surface binding without forming any hydrogen bond. Drosophila larvae fed on these dyes exhibited a dose-dependent increase in acetyl choline esterase enzymatic activity (1.8 fold increase with Disperse black-9, 100 mg/mL) while 4.4-folds Disperse blue-124, 100 mg/mL). Both Disperse Blue and Disperse Black dyes altered the activities of antioxidant enzymes Catalase (CAT, increased more than 2.5 fold), Superoxide dismutase (SOD, increased more than two folds) and showed a dose-dependent increase in Xanthine oxidase and lipid peroxidation (LPO) levels (more than 3 folds). Therefore both the disperse dyes were found to dysregulate the activities of antioxidant enzymes which may be the underlying mechanism for their toxic effects.