A trihydroxyanthraquinone that is 9,10-anthraquinone which is substituted by hydroxy groups at positions 1, 3, and 8 and by a methyl group at position 6. It is present in the roots and barks of numerous plants (particularly rhubarb and buckthorn), moulds, and lichens. It is an active ingredient of various Chinese herbs. ChEBI: Emodin is a trihydroxyanthraquinone that is 9,10-anthraquinone which is substituted by hydroxy groups at positions 1, 3, and 8 and by a methyl group at position 6. It is present in the roots and barks of numerous plants (particularly rhubarb and buckthorn), moulds, and lichens. It is an active ingredient of various Chinese herbs. It has a role as an antineoplastic agent, a tyrosine kinase inhibitor, a laxative and a plant metabolite. It is functionally related to an emodin anthrone. It is a conjugate acid of an emodin(1-).