Tetrahydroxyquinone

Tetrahydroxyquinone (Tetrahydroxy-1,4-benzoquinone), a primitive anticataract agent, is a redox active benzoquinone. Tetrahydroxyquinone can take part in a redox cycle with semiquinone radicals, leading to the formation of reactive oxygen species (ROS)^[1]. In Vitro: Tetrahydroxyquinone (100-500 μM; 24 hours; HL60 cells) treatment shows cytotoxic for HL60 leukaemia cells by total protein content (IC₅₀ of 20 µM), phosphatase activity (IC₅₀ of 40 µM), or by MTT assay (IC₅₀ of 45 µM). Tetrahydroxyquinone is an efficient inducer of ROS production in HL60 leukaemia cells^[1].
Tetrahydroxyquinone efficiently activates caspase 3 in concentration in excess of 25 µM, stimulates DNA fragmentation at the same concentration and provoke phosphatidylserine exposure^[1].
Tetrahydroxyquinone induces the release of cytochrome c from the mitochondria at concentration as low as 25 µM. Tetrahydroxyquinone treatment also causes increase of phosphorylation of Ser473 in protein kinase B (the Bad kinase for Ser112)^[1].