Even though the mechanism of roylaneone compound inhibition of cancer cells is not yet determined as exclusively through inhibition or activation (4 activates PKCδ [15]) of specific PKC isoforms, ParvD (3) has the best calculated interaction profile of compounds 1-3, given its good interactions of the core structure and substituents with Val326 in the PKC binding site, as well as experimental inhibition against all cell types, including the most aggressive form. Here, PRKCD is linked to cancer.