Neriifolin and 2’-Acetylneriifolin: Insecticidal and Cytotoxic Agents of Thevetia thevetioides Seeds

A bioassay procedure utilizing the European corn borer, Ostrinia nubilalis (Hubner), has been used to guide the phytochemical fractionation of active extracts of the seeds of a yellow oleander, Thevetia thevetioides (HBK.) K. Schum. (Apocynaceae). The known cardiotonic glycosides, neriifolin and 2’-acetylneriifolin, were crystallized as the active insecticidal agents, giving LD50 determinations of 30 ppm and 192 ppm, respectively, when incorporated into the corn borer diet. These compounds also exhibited cytotoxic activities of 2.2×10−2 and 3.3 × 10−2 μg/ml, respectively, in the KB (human nasopharynx epidermoid carcinoma) in vitro system. The glucoside of β-sitosterol also was isolated but it lacked insecticidal activity.