Disclosed are bruceolides for the treatment of cancer, and oilier diseases, selectively targeting unwanted cells. The disclosed bruceolides may include a site specific cleavable moiety inhibiting the chemotoxic activity until cleaved, i.e., removed, within and/or near a cancer to be treated. As to facilitate selective delivery to cancer tumors, the disclosed bruceolides may be loaded into, attached to or otherwise carried by nanoparticles.