Antibacterial activity of etanolic extracts of insects and spiders
Antibacterial activity of etanolic extracts of insects and spiders

Summary/Abstract: Despite the fact that preparations made from insects and spiders can be used against microorganisms that are pathogenic to humans and animals, their potential in this relation has not been explored fully. We studied the effects of ethanolic extracts of 12 insects belonging to the families Tettigoniidae, Oecanthidae, Acrididae, Forficulidae, Pyrrhocoridae, Pentatomidae, Carabidae, Coccinellidae, Erebidae, and Vespidae and four spiders of the families Araneidae and Lycosidae. Growth inhibition zones that exceeded six millimeters were produced by the following ethanolic extracts: the firebug Pyrrhocoris apterus against five species of microorganisms (Escherichia coli, Klebsiella pneumoniae, Proteus mirabilis, Bacillus subtilis, and Candida albicans), caterpillars of Euproctis chrysorrhoea against four species (Proteus mirabilis, Shigella flexneri, Enterococcus faecalis, and Clostridium perfringens), imagoes of Chorthippus dorsatus against four species (Escherichia coli, Proteus mirabilis, Shigella flexneri, and Enterococcus faecalis), and the spider Lycosa singoriensis against four species (Escherichia coli, Proteus mirabilis, Clostridium perfringens, and Candida albicans). During our study of antibacterial and antifungal activities, these insects and spiders turned out to be the most promising for further studies on in vivo antibacterial activity. At the same time, the least encouraging results were produced by Calathus fuscipes, Harmonia axyridis, Coccinella septempunctata, Forficula auricularia, and Araneus marmoreus. The ethanolic extracts of the insects Pyrrhocoris apterus, Chorthippus dorsatus, Tettigonia viridissima, and Oecanthus pellucens, and also the spider Lycosa singoriensis had the highest inhibitory activity against E. coli. A moderate inhibition of the growth of E. coli was demonstrated by the extracts derived from Forficula auricularia, Palomena prasina, and Araneus diadematus. A significant activity toward the bacterium Klebsiella pneumoniae was displayed by the extracts of P. apterus and T. viridissima, and a moderate activity was demonstrated by the Harpalus rufipes extract. Proteus mirabilis was observed to be highly sensitive to the extracts of Eu. chrysorrhoea, P. gallicus, Ch. dorsatus, P. apterus, T. viridissima, and Oe. pellucens and the extract of L. singoriensis. The bacterium P. mirabilis was moderately sensitive to two extracts from the ground beetles, H. rufipes and C. fuscipes. The most intense inhibition of the growth of the bacterium Shigella flexneri was produced by the extracts from the insects Eu. chrysorrhoea, Ch. dorsatus, C. septempunctata, and also the spider Argiope bruennichi. No ethanolic extracts of the insects and spiders inhibited the growth of Pseudomonas aeruginosa and Listeria monocytogenes. A high antimicrobial activity against E. faecalis was exhibited by the extracts of the insects P. gallicus, Eu. chrysorrhoea, Ch. dorsatus, P. prasina, and Oe. pellucens, and also the ethanolic extracts of the spiders A. bruennichi and A. diadematus. The bacterium Staphylococcus aureus was low-sensitive to the alcohol extracts of three insects and one spider. Only the alcohol extract of P. apterus effectively inhibited the growth of the colonies of Bacillus subtilis. A notable inhibitory action toward the bacterium Clostridium perfringens was displayed by the extracts of Eu. chrysorrhoea, P. prasina, A. diadematus, and L. singoriensis. Of all the tested samples of alcohol extracts of insects and spiders, a fungicidal activity against Candida albicans was exerted by Eu. chrysorrhoea, P. prasina, P. apterus, A. marmoreus, A. diadematus, and L. singoriensis.

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