Cytotoxic triterpenoid saponins from the stem bark of Antonia ovata

Four triterpenoid saponins named antoniosides A-D, were isolated from the stem bark of Antonia ovata (Loganiaceae), along with eleven known compounds. Their structures were established by spectroscopic methods and acid hydrolysis. The cytotoxic activity of isolated saponins was evaluated in vitro against KB cell line.