Defensive chemistry of the flour beetleTribolium brevicornis (LeC): : Presence of known and potential prostaglandin synthetase inhibitors.

The defensive secretion ofTribolium brevicornis contains 12 organic components, including quinones, hydroquinones, hydrocarbons, aromatic ketones, and aromatic esters. The two ketones, 2'-hydroxy-4'-methoxyacetophenone and 2'-hydroxy-4'-methoxypropiophenone, and the two esters, methyl 2,5-dihydroxy-6-methylbenzoate and methyl 2,5-dihydroxy-6-ethylbenzoate, represent ca. 0.25% of the biomass of the beetles. Mass spectral and NMR analyses were used to elucidate the structures of all components. The ketones are potent prostaglandin synthetase inhibitors (PSI), and the esters are suspected to be PSI.