The effect of niclosarnide on some biological and physiological aspects of Galleria mellonella L. (Lepidoptera: Pyralidae)

The salisilanilides function by inhibiting nnitocondrial oxidative phosphorylation in parasitic tapeworms and thus they are used as an antiparasitic drug in medicine and veterinary. While the potent antihelmintic activity of niclosamide has been well characterised in mammals, this study investigated the in vivo insecticide effect of niclosamide using larvae of the insect Galleria mellonella. Niclosamide was successful in decreasing the survival of 7th instar larvae, pupal and adult stages while only the highest concentration of this antihelmintic antibiotic (1.0 %) significantly prolonged developmental time to adult stage. Fecundity of females was obtained as 78.6 +/- 6.1 number of eggs/day/female in control diet. Fecundity were increased to 114.7 +/- 10.9 at 0.1% of niclosamide. However, we could not obtain any egg at the highest concentration. An increase in the male adult longevity was obtained when reared with the highest concentrations of niclosamide. Niclosamid rearing resulted in a decrease in hatchability of eggs. Niclosamide at 0.1 % of concentration increased malondialdehyde (MDA) content (4-fold), glutathion-S-transferase (GST) activity (2-fold). Relative to control (133.24 +/- 23.6 nmol/mg protein), niclosamide at tested concentrations significantly increased protein carbonyl (PCO) content at least 5-fold (701.24- 808.02 nmol/mg protein). This work indicates that G. mellonella larvae may be used as a good model to ascertain importance of clincally important antihelmintic drug active ingredients in chemical management of pest insects. The results of this work also indicate that the negative effects of niclosamide on insect biology are due to its pro-oxidant properties and also to the ability of niclosamide in crippling the insect's antioxidan defence response.