Morinda citrifolia (Noni)

January 2001; Volume 3; 5-7

By Jerry Cott, PhD

Hawked as a panacea, noni fruit juice has been marketed heavily in the United States since the early 1990s. Promotion of this product primarily has been through network marketing companies that distribute exaggerated claims and testimonials for noni’s purported benefits as a general tonic and for a variety of diseases, including cancer, heart disease, diabetes, hypertension, arthritis, stroke, gastrointestinal disorders, malaria, depression, and drug addiction.1

Traditional Use

Morinda citrifolia (family Rubiaceae), also known as noni, or Indian mulberry, is a small evergreen shrub or tree that grows up to 10 feet high. Native to the Pacific islands, Polynesia, Asia, and Australia, noni has large, dark green, deeply veined, shiny leaves; small white flowers; and warty, pitted, three- to four-inch long fruits that start out green and turn yellow and then white with ripening. The ripe fruit has a foul odor due to short-chain carboxylic acids.

On its native soil, noni fruit generally is not considered edible, although the unripe fruit (less noxious than the ripe fruit) may be eaten. Traditional Hawaiian healers apparently have used the fruit medicinally as a purgative, cleanser, blood purifier, and more recently for intestinal worms and for tuberculosis.1 However, it is said that only sick and desperate people will consume noni fruit because of its unpleasant odor and bitter taste. The indigenous medicinal use of this plant, however, utilizes not the fruit but the leaves, primarily as a topical treatment for wound healing. In Chinese medicine, M. officinalis root is a standard medication (known as bai ji tian or pa chi tien) used for the digestive system, kidneys, heart, and liver. In addition, a red dye is made from the bark and a yellow dye from the root.

Contemporary Claims

Noni fruit juice or extract has been marketed as a treatment for a variety of diseases. Noni marketers claim that the key medicinal component of noni is an alkaloid called "xeronine."2 However, a thorough review of the chemical literature does not substantiate the existence of such a compound, and the person credited with discovering xeronine, Dr. Heinicke, did not publish any of his findings. Xeronine appears to exist only in promotional materials for noni.

Commercial products usually contain noni juice or a juice concentrate. The carboxylic acids that give noni its foul smell are not present to any great extent in the marketed products, which also often incorporate other fruit juices or flavorings to make preparations more palatable. The usual dose for juice products is the equivalent of four ounces noni juice 30 minutes before breakfast.

Tablets and capsules containing the fruit and the whole plant also are available. For liquid concentrates the typical recommendation is two tablespoons daily, and for powdered extracts the recommended dose is 500-1,000 mg/d. It is suggested that noni be taken on an empty stomach (to maximize absorption and "activation" of xeronine).

Pharmacology

The leaves of M. citrifolia and other Morinda species contain high levels of vitamins and minerals, including vitamin C, beta-carotene, calcium, iron, phosphorus, niacin, riboflavin, and thiamin.

According to the USDA Phytochemical Database, M. citrifolia root constituents include morindin, rubichloric acid, rubiadin-1-methyl ether, soranjidiol, asperuloside, nordamnacanthal, and trihydroxyanthraquinones (re-
sponsible for the mild laxative effect). The ripe fruit is characterized by a large amount of carboxylic acids (which account for its odor), primarily hexanoic and octanoic acids. In addition, Levand and Larson reported caproic and caprylic acids and asperuloside in the fruit.3

Ripe fruit contains hexanoic and octanoic acids;4 the toxicity of these acids makes microbial contamination of fruits less likely than with other plant products.5 However, these toxic acids apparently don’t bother one species of fruit fly, which chooses to lay its eggs in the fruit.6

Evidence

No human clinical trials have been conducted, and no animal studies have been performed that would approximate human usage of the plant. Intraperitoneal doses (300-750 mg/kg) of a polysaccharide-rich substance extracted from the fruit juice may have anticancer activity in the Lewis lung carcinoma model in mice.7-9 However, since both the noni extract and the tumor cells were administered by intraperitoneal injection, the effects reported may not apply to noni given orally. When applied to tumor cells in vitro, a more purified formulation than the one that was injected into the mice showed direct cytotoxicity only at high concentrations.9 However, this lack of direct toxicity does not apply to the mouse carcinoma study since it was a different formulation.

An in vitro study from Japan found that high concentrations (5-20 mcg/mL) of damnacanthal, a purified anthraquinone compound from a chloroform extract of the root, may have immune-enhancing activities.10 Other studies show that damnacanthal inhibits tyrosine kinase and stimulates UV-induced apoptosis.11 Whether these effects are related to the activity of the fruit extract in the lung carcinoma model is unknown, but seems doubtful.

The lyophilized aqueous extract of M. citrifolia root was evaluated in another study that examined analgesic and behavioral effects in mice.12 Intraperitoneal doses of 800 and 1,600 mg/kg had analgesic activity in standard writhing and hot plate tests that was reversed by the narcotic antagonist naloxone. Administration of 500-1,600 mg/kg of the extract decreased all behavioral parameters suggesting general sedative properties. However, any relevance of these huge intraperitoneal doses of root extracts to therapeutic oral ingestion of the fruit material seems very doubtful.

Extracts from other Morinda species have been reported to possess anti-diabetic,13 anti-malarial,14 and anti-parasitic15 activities in in vitro and animal studies. Whether any of these properties can also be attributed to M. citrifolia fruit has not been established.

Risks and Side Effects

Although adverse effects have not been reported with noni, no safety studies have been performed. The potassium content is similar to that in orange juice, and noni juice consumption was linked to hyperkalemia in a patient with chronic renal insufficiency.16 Because of the lack of data, use of noni by pregnant or nursing women, or those with liver or kidney disease, is not recommended.

In summary, although noni fruit products appear benign, they have not yet been proven effective for any condition in humans. In addition, the fruit is not an important part of traditional medicine in its native lands. The scant animal and in vitro data that exist are primarily on other parts of M. citrifolia or other species of Morinda and cannot be extrapolated to noni fruit products. v

Dr. Cott is Scientific Director and Chief Science Officer at Scientific Herbal Products, Inc. in College Park, MD.

References

1. Dixon AR, et al. Ferment this: The transformation of noni, a traditional Polynesian medicine (Morinda citrifolia, Rubiaceae). Economic Botany 1999;53:51-68.

2. Elkins R. Hawaiian noni (Morinda citrifolia). Pleasant Grove, Utah: Woodland Publishing; 1998.

3. Levand O, Larson HO. Some chemical constituents of Morinda citrifolia. Planta Med 1979;36:186-187.

4. Farine JP. Volatile components of ripe fruits of Morinda citrifolia and their effects on Drosophila. Phytochemistry 1996;41:433-438.

5. Limyati DA, Juniar BL. Jamu Gendong, a kind of traditional medicine in Indonesia: The microbial contamination of its raw materials and endproduct. J Ethnopharmacol 1998;63:201-208.

6. Jones CD. The genetic basis of Drosophila sechellia’s resistance to a host plant toxin. Genetics 1998;149:
1899-1908.

7. Hirazumi A, et al. Anticancer activity of Morinda citrifolia (noni) on intraperitoneally implanted Lewis lung carcinoma in syngeneic mice. Proc West Pharmacol Soc 1994;37:145-146.

8. Hirazumi A, et al. Immunomodulation contributes to the anticancer activity of Morinda citrifolia (noni) fruit juice. Proc West Pharmacol Soc 1996;39:7-9.

9. Hirazumi A, Furusawa E. An immunomodulatory polysaccharide-rich substance from the fruit juice of Morinda citrifolia (noni) with antitumour activity. Phytother Res 1999;13:380-387.

10. Hiramatsu T, et al. Induction of normal phenotypes in ras-transformed cells by damnacanthal from Morinda citrifolia. Cancer Lett 1993;73:161-166.

11. Hiwasa T, et al. Stimulation of ultraviolet-induced apoptosis of human fibroblast UVr-1 cells by tyrosine kinase inhibitors. FEBS Lett 1999;444:173-176.

12. Younos C, et al. Analgesic and behavioural effects of Morinda citrifolia. Planta Med 1990;56:430-434.

13. Olajide OA, et al. Evaluation of the anti-diabetic property of Morinda lucida leaves in streptozotocin-diabetic rats. J Pharm Pharmacol 1999;51:1321-1324.

14. Sittie AA, et al. Structure-activity studies: In vitro antileishmanial and antimalarial activities of anthraquinones from Morinda lucida. Planta Med 1999;65:259-261.

15. Raj RK. Screening of indigenous plants for anthelmintic action against human Ascaris lumbricoides: Part II. Indian J Physiol Pharmacol 1975;19.

16. Mueller BA, et al. Noni juice (Morinda citrifolia): Hidden potential for hyperkalemia? Am J Kidney Dis 2000;35:310-312.