Analysis of cockroach oothecae and exuviae by solid-state 13C-NMR spectroscopy

Sclerotized oothecae from four species of cockroaches, Periplaneta americana, P. fuliginosa, Blatta orientalis and Blattella germanica, were examined by solid-state ¹³C-nuclear magnetic resonance and chemical analyses. The oothecae were composed of protein, water, calcium oxalate, diphenolic compounds, lipid, and uric acid. Calcium oxalate was the major soluble component in egg cases of P. americana, P. fuliginosa, and B. orientalis. Oothecae of B. germanica had approx. 10-fold less calcium oxalate and extractable diphenols than the other species. The major diphenolic compound extracted in cold dilute perchloric acid was 3,4-dihydroxybenzoic acid. Exuviae from P. americana, B. germanica, Gromphadorhina portentosa, Blaberus craniifer, and Leucophaea maderae also were examined by solid-state ¹³C-NMR. They contained protein, diphenols, and lipid, as well as chitin, which accounted for 30–42% of the organic content, depending upon the species.