Delphinium alkaloids as inhibitors of α-bungarotoxin binding to rat and insect neural membranes

Abstract

A series of C19-diterpenoid alkaloids purified from Delphinium were evaluated as inhibitors of α-bungarotoxin binding to rat and house fly neural membranes. In comparing these diterpenoid analogs, a wide range of inhibition potencies (IC50) were observed, with calculated IC50 values ranging six orders of magnitude. The most potent inhibitory alkaloids in this series possessed the succinimide aromatic ester moiety in the C18 position. Glaudelsine had an IC50 value of 42 pM at the insect nicotinic acetylcholine receptor.Key words: nicotinic, acetylcholine, delphinium, diterpenoid.