Potato leaf extract and its component, α-solanine, exert similar impacts on development and oxidative stress in Galleria mellonella L.

Plants synthesize a broad range of secondary metabolites which act as natural defenses against plant pathogens and herbivores. Among these, potato plants produce glycoalkaloids (GAs). In this study we analyzed the effects of the dried extract of fresh potato leaves (EPL) on the biological parameters of the lepidopteran, Galleria mellonella (L.) and compared its activity to one of the main EPL components, the GA α-solanine. Wax moth larvae were reared from first instar on a diet supplemented with three concentrations of EPL or α-solanine. Both EPL and α-solanine affected survivorship, fecundity and fertility of G. mellonella to approximately the same extent. We evaluated the effect of EPL and -solanine on oxidative stress in midgut and fat body by measuring malondialdehyde (MDA) and protein carbonyl (PCO) contents, both biomarkers of oxidative damage. We evaluated glutathione S-transferase (GST) activity, a detoxifying enzyme acting in prevention of oxidative damage. EPL and -solanine altered MDA and PCO concentrations and GST activity in fat body and midgut. We infer that the influence of EPL on G. mellonella is not enhanced by synergistic effects of the totality of potato leaf components compared to α-solanine alone.