What is Anthraquinone?

Karyn Maier
Karyn Maier

Anthraquinone is an aromatic organic compound that occurs naturally in certain plants, fungi and insects. Since it contributes to the coloring pigment of such organisms, the compound is used commercially to manufacture dyes. In powdered form, anthraquinone exhibits a color that ranges from gray to yellow and green. However, it produces a variety of different colored dyes, including alizarin (red), oil blue A and oil blue 35, quinizarine green SS and solvent violet 13.

Anthraquinone is found in senna pods.
Anthraquinone is found in senna pods.

This compound can also be mechanically produced by oxidizing anthracene with chromic acid, or by reducing benzene and phthalic anhydride. The latter method requires hydration before the mixture can be considered as anthraquinone.

Anthraquinone has been linked to a condition known as melanosis coli, a discoloration of the colon wall.
Anthraquinone has been linked to a condition known as melanosis coli, a discoloration of the colon wall.

Anthraquinone is known by many other names, such as anthrachinon, dioxoanthracene, and several different trade names, including Hoelite and Corbit. It is a derivative of anthracene, a coal-tar byproduct characterized by a chemical structure consisting of a polycyclic aromatic hydrocarbon and three fused rings of benzene.

There are other commercial applications for anthraquinone in addition to producing dyes. For example, it is used as a catalyst in the production of wood pulp and paper. A derivative called 2-ethylanthraquinone is used to manufacture hydrogen peroxide. Anthraquinone has a long history of use as a bird repellent and is used to deter the presence of geese in particular. This action may be due to the laxative properties that the compound possesses when introduced as treated birdseed or grass. In fact, its presence is what lends laxative qualities to several well-known herbs used to treat constipation, such as senna pods, aloe, rhubarb, buckthorn and cascara sagrada.

There are a number of environmental and health concerns associated with anthraquinone. For one thing, its use as a laxative has been linked to a benign but undesirable condition known as melanosis coli, which is characterized by a discoloration of the colon wall.

Two-year studies conducted by the National Toxicology Program (NTP) using animal models indicate that anthraquinone is a liver carcinogen when ingested. These tests also produced evidence that this compound may cause non-cancerous lesions or tumors to appear on various organs. In addition, research conducted by NTP suggests that it may be an endocrine disruptor. As a result of NTP’s findings, the California Environmental Protection Agency included anthraquinone to its list of established carcinogens.

Anthraquinone also presents certain safety challenges to the manufacturing industry. For instance, the substance is highly combustible and cannot be used near an open flame or extreme heat since the compound produces toxic fumes when burned. It is also recommended that workers handling anthraquinone wear a P1 filter respirator to avoid inhaling inert particles, as well as protective gloves and eyewear. Environmentally, the compound is toxic to fish and does not readily biodegrade.

Karyn Maier
Karyn Maier

Contributing articles to wiseGEEK is just one of Karyn’s many professional endeavors. She is also a magazine writer and columnist, mainly for health-related publications, as well as the author of four books. Karyn lives in New York’s Catskill Mountain region and specializes in topics about green living and botanical medicine.

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Discussion Comments


@Pippinwhite --Wow. That really is something to think about! I always loved Bob Ross. I know a lot of people would say he's hokey, but really, he did a kind of painting a lot of people can do, and his show is "The Joy of Painting," not "the high art of painting."

Anyway, that's an interesting hypothesis, if this stuff is used in art oil paints.

I'd be interested in knowing if there are any warnings on paint tubes about it, and whether the manufacturers recommend using a breathing mask while using the oils.


Well, I'd wondered how some paint got its pigment and now I know. The carcinogenic nature of the anthraquinone makes me wonder about something, though. The painter on TV, Bob Ross, died from cancer, and I know he used a lot of the alizarin red paint in his work. Does this oil paint contain anthraquinone, if it does, I wonder if it's safe to use?

Ross died from lymphoma, but if he had used some other kind of red paint, I wonder if he would have still gotten the cancer. In other words, could his cancer have been linked to the alizarin red paint he used? It's an interesting question, I think, and one I'd pursue if I were going to do much painting. I would at least wear a breathing mask, I think.

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