Dimeric N -Acetyldopamine Derivatives Featuring a Seco-Benzene System from the Insects Aspongopus chinensis and Periostracum cicadae .

Aspongamide F ( 1 ), a novel N -acetyldopamine (NADA) dimer possessing a 6/6/6 ring system, and (±)-aspongamides G ( 2 ) and H ( 3 ), rare NADA derivatives with fragmented benzene rings, were isolated from Aspongopus chinensis . (±)-Cicadamides C ( 4 ) and D ( 5 ), the first 1,4-Benzodioxane NADA dimers featuring a seco-benzene system, and (±)-cicadamides E ( 6 ) and F ( 7 ), the NADA dimers derivatives, were isolated from Periostracum cicadae . The structures of all compounds were elucidated by spectroscopic analyses and computational methods. A plausible biosynthetic pathway for compounds 1 - 5 was proposed. The biological assay revealed that (+)- 4 and (-)- 4 exhibit renal protection in a dose-dependent manner.