A quinonoid constituent isolated from the root of Plumbago zeylanica. Displays anticarcinogenic, antiatherosclerotic, and antimicrobial effects as well as anticancer and antiproliferation properties in a variety of cell lines and animal models. Induces G2/M and autophagy in breast cancer cells by inhibiting Akt/mTOR pathway. Also potently inhibits histone acetyltransferase (HAT) activity in vivo. Plumbagin specifically inhibits p300-mediated acetylation of p53 but not the acetylation by p300/CREB-binding protein associated factor, PCAF, in vivo.