has part has role antioxidant physical tracer antidepressant antineoplastic agent organic chloride salt EC 3.1.1.8 (cholinesterase) inhibitor antimalarial EC 1.4.3.4 (monoamine oxidase) inhibitor 3,7-bis(dimethylamino)phenothiazin-5-ium benzothiazine acid-base indicator fluorochrome neuroprotective agent methylene blue CHEBI:6872 An organic chloride salt having 3,7-bis(dimethylamino)phenothiazin-5-ium as the counterion. A commonly used dye that also exhibits antioxidant, antimalarial, antidepressant and cardioprotective properties. histological dye cardioprotective agent EC 4.6.1.2 (guanylate cyclase) inhibitor