Establishment of a Phenotypic-based Sand Dollar Fellaster zelandiae Embryo Development Assay and its Application in Defining the Structure-Activity Relationship of Discorhabdin Alkaloids

Abstract

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.