Cicadamides A and B, N-Acetyldopamine Dimers From the Insect Periostracum cicadae

Two new N-acetyldopamine dimers, cicadamides A (1) and B (2), and 8 known compounds were isolated from the medicinal insect Periostracum cicadae. Their structures including absolute configurations were assigned by spectroscopic and computational methods. Biological activities of compounds 1, (+)-2, and (–)-2 toward human cancer cells BGC-823, HepG2, and A549 were evaluated.