Quinalizarin

Quinalizarin or 1,2,5,8-tetrahydroxyanthraquinone is an organic compound with formula . It is one of many tetrahydroxyanthraquinone isomers, formally derived from anthraquinone by replacement of four hydrogen atoms by hydroxyl (OH) groups.
Quinalizarin is an inhibitor of the enzyme protein kinase CK2. It is more potent and selective than emodin. It is also a potent catechol O-methyltransferase (COMT) inhibitor.