Syntheses and Biological Activities of Joro Spider Toxin Analogs to Spidamine and Joramine

In order to study the structure-activity relationships of spidamine and joramine found in the venom of Joro spider, Nephila clavata, we attempted to synthesize various analogs. Six analogs were convergently synthesized according to our previous method for the synthesis of spidamine, N-(3-aminopropyl-β-alanyl)-N'-(2, 4-dihydroxy-phenylacetyl-L-asparaginyl)-1, 5-pentanediamine and joramine, N-(3-aminopropyl-β-alanyl)-N'-(4-hydroxyphenyl-acetyl-L-asparaginyl)-1, 5-pentanediamine. The biological activities of the analogs and four intermediates were compared with those of synthetic spidamine and joramine in three bioassay systems, lobster neuromuscular synapse, cockroaches and mosquito larvae. The glutamate receptors in these systems were inhibited by some analogs, and the D-asparagine- or indoleacetyl-containing analogs were found to be strong inhibitors. These compounds have potential application as insecticides.