Solanum nigrum Extract and Solasonine Affected Hemolymph Metabolites and Ultrastructure of the Fat Body and the Midgut in Galleria mellonella.

Marta Spochacz,Marisa Nardiello,Paweł Marciniak,Laura Scrano,Carmen Scieuzo,Szymon Chowański,Sabino A Bufo,Filomena Lelario,Rosanna Salvia,Zbigniew Adamski,Monika Szymczak-Cendlak,Patrizia Falabella

doi:10.3390/toxins13090617

Marta Spochacz, Marisa Nardiello + Show 10 more

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https://doi.org/10.3390/toxins13090617

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Abstract

Glycoalkaloids, secondary metabolites abundant in plants belonging to the Solanaceae family, may affect the physiology of insect pests. This paper presents original results dealing with the influence of a crude extract obtained from Solanum nigrum unripe berries and its main constituent, solasonine, on the physiology of Galleria mellonella (Lepidoptera) that can be used as an alternative bioinsecticide. G. mellonella IV instar larvae were treated with S. nigrum extract and solasonine at different concentrations. The effects of extract and solasonine were evaluated analyzing changes in carbohydrate and amino acid composition in hemolymph by RP-HPLC and in the ultrastructure of the fat body cells by TEM. Both extract and solasonine changed the level of hemolymph metabolites and the ultrastructure of the fat body and the midgut cells. In particular, the extract increased the erythritol level in the hemolymph compared to control, enlarged the intracellular space in fat body cells, and decreased cytoplasm and lipid droplets electron density. The solasonine, tested with three concentrations, caused the decrease of cytoplasm electron density in both fat body and midgut cells. Obtained results highlighted the disturbance of the midgut and the fat body due to glycoalkaloids and the potential role of hemolymph ingredients in its detoxification. These findings suggest a possible application of glycoalkaloids as a natural insecticide in the pest control of G. mellonella larvae.

Highlights

Introduction distributed under the terms andPlant derivatives have been extensively studied for their efficacy against many insect species to prove their insecticidal properties [1,2,3,4]
During the HPLC analysis performed on hemolymph samples derived from control larvae and larvae fed on the extract and on the pure glycoalkaloids at different concentrations, 19 peaks appeared representing 15 compounds, among which 7 were identified (Figure 1)
The mean values of its level in the hemolymph of larvae treated with the S. nigrum extract (Ext) and three solasonine concentrations were higher than the mean value of the control

Summary

Introduction

Introduction distributed under the terms andPlant derivatives have been extensively studied for their efficacy against many insect species to prove their insecticidal properties [1,2,3,4]. Black nightshade (Solanum nigrum) is a member of the Solanaceae family, the same as potato (Solanum tuberosum) or tomato (Solanum lycopersicum). These plants contain secondary metabolites, glycoalkaloids, that conditions of the Creative Commons. S. nigrum contains the highest amounts of two main glycoalkaloids: solasonine and solamargine. Both S. nigrum unripe berries extract and pure glycoalkaloids were tested previously for insecticidal activity on coleopteran insects, confirming their sublethal effect [2,5,6]. Products from Solanaceae plants tested on lepidopteran models showed lethal, sublethal, or no effects [7].

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