Anthraquinone

Anthraquinone is the class-defining compound for a number of naturally-occurring plant pigments. Anthraquinone itself has been associated with causing liver, bladder and kidney cancers, and other non-neoplastic disorders. . It also, however, has been a starting point for developing antineoplastic agents, especially the anthracycline agents, of which doxorubricin (Adriamycin) is best known.

The plant Rheum palmatum, called Indian rhubarb in North America and also used in traditional Chinese medicine is rich in anthraquinones. Indian rhubarb is a constituent of the herbal cancer treatment, Essiac. Extracts of the plant have shown activity against hepatitis B virus.

Aloe-emodin (1,8-dihydroxy-3-(hydroxymethyl)-anthraquinone) is an active component from the root and rhizome of R. palmatum. Activation of caspase-3, caspase-8, and caspase-9 is an important determinant of apoptotic death induced by aloe-emodin. These results suggest that aloe-emodin induces cell death in a human lung squamous cell carcinoma line, CH27, by the Bax and Fas death pathway.