An embryo development assay using the common New Zealand intertidal species Fellaster zelandiae (sand dollar) is presented. The assay was validated by comparing activity profiles of a range of discorhabdin alkaloids, natural products sourced from Latrunculia spp. sponges containing a core pyrido[2,3- h]pyrrolo[4,3,2- de]quinoline tetracyclic skeleton bound to various spiro-substituents at the C-6 position. Structural features on the discorhabdin molecule that correlated to the greatest degree of F. zelandiae embryo developmental inhibition were the presence of a spiro-dienone moiety and a C-2 bromine substituent. Based on the sand dollar embryo development assay results, a mechanism for the activity of the discorhabdin alkaloids is proposed.
Structure–Activity Relationship of Cytotoxic Natural Products from Indonesian Marine Sponges
