Cardenolides from Antiaris toxicaria as potent selective Nur77 modulators.

Toxicarioside D (1), a new cardenolide, along with 10 other known ones, was isolated from the stem of Antiaris toxicaria LESCH. by bioassay-guided fractionation. Their structures were determined on the basis of spectroscopic analysis. All the reported compounds effectively inhibited the growth of various cancer cell lines at nanomolar concentrations. Inhibition of cancer cell growth was accompanied with induction of the expression of Nur77, a potent apoptotic member of the steroid/thyroid hormone receptor superfamily.