Some anthraquinones have been used more commonly as dyes and pigments and analytical reagents in research studies.

However, anthraquinones have a wide variety of biological activities attributed to them. They also have very low toxicity. Some of this biological activity includes fighting inflammation, bacteria, parasites and tumours. Some of these compounds are also considered analgesics (pain relievers). Studies with Morinda citrifolia have confirmed the juice of this plant to be strongly analgesic (ie. pain-relieving). In fact such studies indicate it is 75% as effective as morphine sulphate without the toxic side effects of morphine. research studies.

Anthraquinones are also used to fight fungal infections as well as possessing the ability to improve the immunity of the body. Anthraquinones participate in the processes of metabolism, cellular respiration and growth. As a result of research carried out in Japan in 1993 it is now believed that damnacanthal, one of this group of compounds, is able to inhibit the formation of tumours by interfering with the growth of RAS Cells.

These cells are the precursors of many malignant growths. It is also believed that damnacanthal and some of the other anthraquinones may cut off the blood supply to tumours, thereby depriving them of their nutrients. This could account for the many stories from medical practitioners and cancer patients alike about the reduction of tumour size after having drunk large quantities of Noni juice for some time.
In another summary of research carried out in Poland, the researchers wrote: "Anthraquinone compounds belong to the most important class of clinical anti tumour agents."

These researchers also note that the anthraquinones may be responsible for some ,damaging peroxidating activity which is damage done to cells by oxidation. However, when anthraquinones are found in a synergistic formula such as Noni juice, then the strong anti-oxidant effects of other components, such as beta-carotene will overcome many negative effects. Beta-carotene mops up free radicals of oxygen very efficiently.

Evidence suggests that anti oxidants in Noni include beta carotene, vitamins E & C, and c %stine which combat the potentiallv destructive oxidative effects of the environment in our cells. A basic requirement of good health is our hody's ability to supply adequate anti-oxidants to meet our requirements.
Turning our attention once more to Japan, we find that in 1998 a study was conducted investigating the biological activities of the anthraquinones damnacanthal, rubiadin, nor-damnacanthal, morindone and lucidin 3-0primeverodise. The results of this work demonstrate that these particular substances show a powerful slowing effect on the growth of tumours by inhibiting important enzymes needed to form tumours.

Extracts of damnacanthal have been shown to kill the parasite Plasmodium falciparum, the organism that causes malaria. Malaria is considered one of the biggest health problems in the world today, especially in developing nations. During World War II this disease was a major challenge to troops. It was recorded that five times as many soldiers in the South Pacific area were incapacitated by malaria than by combat. Plasmodium falciparum and P. vivax (another form of the parasite) account for over 95% of malarial infections in the world world today.

This makes any substance containing damnacanthal extremely important in the tropical areas where the malarial parasite abounds. It is probably no coincidence that Noni is plentiful in such areas.
Damnacanthal is also potent against leishmaniasis, a parasitic condition common in Central and South America, North East and Central Africa, the Mediterranean and Asia. This unpleasant and debilitating parasitic disease is carried by a species of fly which transmits the parasite in its saliva when it bites the victim. Skin and mucous membrane (such as the mouth and nasal passages) lesions result and if left untreated develop into a severe ulcerative condition.

Alizarin, another anthraquinone, is the parent form of many dyes and pigments used in industry and medical research. It also has some medical applications and has proven itself to be another useful combatant in the fight against leishmaniasis when taken together with other drugs used for the same purpose.
It is of interest that in nature where we ,find a disorder or a threat to our health, there is often an antidote close by, usually as part of the plant kingdom. All we need to do is to find it.
Alizarin also slows tumor growth as well as fighting leukemia

It is of interest to note that alizarin also inhibits the human immunodeficiency virus HIV

Some anthraquinones isolated from other plants were found to significantly "tie up" the mineral calcium and reduce the growth rate of urinary crystals

This is good news for those affected with gout or kidney stones.