Volatile secretion of Ulomoides dermestoides (Coleoptera: Tenebrionidae): Their toxic effects on human cells. Markers of beetle fitness

JUAREZ M.P.; PEDRINI N.; CRESPO R.; VILLAVERDE, L.; GARCÍA DE BRAVO, M.; JUAN R. GIROTTI

Congreso; Symposium of Chemical Ecology and RES National Science Meeting; 2011

Ulomoides dermestoides (Fairmaire, 1893) is a cosmopolitan tenebrionid beetle widely used as an alternative medicine in the treatment of different illnesses, specially cancer. Beetles are reared by people who consume them alive to avoid the loss of their stress secretions. The major components released by stressed insects are methyl-1, 4-benzoquinones, ethyl-1, 4-benzoquinones and 1-pentadecene. Quinones are generally cytotoxic and/or genotoxic compounds by the formation of reactive oxygen species and covalent binding to macromolecules. The defense compounds of U. dermestoides were extracted and their toxicity effects against A549 cell line evaluated. Cytotoxicity was demonstrated by MTT test and Trypan blue assay, with IC50 values of 0.26 equivalent/ml and 0.34 equivalent/ml respectively (1 equivalent = amount of components extracted per beetle). The synthetic compounds (1, 4-benzoquinone and 1-pentadecene), individually or combined, were also tested. The inhibition of cell proliferation with benzoquinone was similar to that obtained with the insect extract; 1-pentadecene showed no inhibitory effect. The genotoxicity of the beetle´s extract was evaluated by the comet assay. Doses equal or higher than 0.15 equivalent/ml of insect extract induced significant DNA damage in tumor cells. We conclude that the insect benzoquinones are primarily responsible for inducing cytotoxicity and DNA damage in A549 cells.