Toxicological assessment of sodium benzoate in Drosophila melanogaster

Sodium benzoate (SB), the sodium salt of benzoic acid, is a food preservative with wide applications in the food, cosmetic and pharmaceutical industries due to its ability to kill many microorganisms effectively. Experimental evidence however suggests that excessive intake of SB poses detrimental health risks among consumers in the population. The present study investigated the toxic effects of various concentrations of SB using Drosophila melanogaster as a model. Adult wild-type flies of Canton S strain (1- to 3-days old) was orally exposed to SB (0, 0.5, 1.0, 2.0 and 5.0 mg/5 g diet) to evaluate survival rates for 21 days. Thereafter, we evaluated markers of oxidative stress, antioxidant status and behavioral activity in D. melanogaster exposed to SB for seven (7) days. We observed that SB (2.0 and 5.0 mg/5 g diet) decreased the survival of D. melanogaster. Also, SB inhibited glutathione-S-transferase activity and depleted total thiols and nonprotein thiols contents. Moreover, SB (5 mg/5 g diet) increased nitric oxide (nitrite/nitrate) level and reduced flies' emergence rate. Conclusively, findings from this study revealed that exposure to high concentrations of SB reduced survival rate and induced toxicity via the induction of oxidative stress and inhibition of antioxidant enzymes in D. melanogaster.