Morinda citrifolia, commonly known as noni, is a small, evergreen tree native to the Pacific islands, southeast Asia, Australia, and India.1 Reaching 10-20 feet in height, the tree often grows along old lava flows and is identified by its straight trunk; large, green, elliptical leaves; and white, tubular flowers. Its yellow oval fruit have a lumpy surface and can grow as large as 12 cm or more.2 The pulp and juice from noni fruit are a dark, reddish brown and have a strong, unappealing flavor. Many commercial preparations combine them with more pleasant-tasting juices, such as pear or grape, to improve the palatability.

Background

Every part of the noni tree is used commercially: fruit, leaves, flowers, stems, bark, and roots. It is the fruit, however, with multipurposes documented over 2,000 years, that is most prized.1 Besides being a source of nutritious food  for both people and livestock, noni is used as a pigment and medicinally as a topical healing agent, antibiotic, antioxidant, immune booster, and analgesic.2 Native Polynesians say noni does everything—from treating the common cold to preventing cancer.

Evidence of effectiveness

Noni’s antioxidant function has been subject to the most scientific research and earned the most validation, although the European Commission’s Health and Consumer Protection Directorate has concluded that the data showed no evidence of being any more beneficial than other fruit juices.2

Meanwhile, here in the United States, NIH’s National Center for Complementary and Alternative Medicine is conducting a clinical trial on noni efficacy and safety, but results have not yet been published.3

However, a literature review by researchers at the University of Illinois in Rockford mentions a clinical trial that randomized 68 current smokers to either placebo or a noni juice concentrate twice daily for 30 days. The trial was designed to examine noni’s antioxidant properties; plasma levels of superoxide anion radical (SAR) and lipid peroxidases (LPOs) were assayed.4

The noni group showed a 23% reduction in LPO level and a 27% reduction in the SAR level, while there was no change at all in the placebo group. This antioxidant activity equated to a level 2.8 times greater than that of vitamin C.4 This oxidative protectant action is being further researched, especially since oxidative damage has been shown to be a key precursor of cancerous cell changes.

Noni’s major active ingredients are vitamin C, potassium, scopoletin, octanoic (or caprylic) acid, terpenoids, vitamin A, linoleic acid, and several essential amino acids.1 Noni also contains an intriguing enzyme precursor for xeronine, a naturally occurring compound thought to be capable of repairing certain defective proteins that directly affect cellular DNA.4 With this action, noni could theoretically address certain metabolic diseases caused by defects in DNA.

Other research has uncovered some interesting oncologic data. Small trials have found evidence of an anti-angiogenic effect in explanted human breast tumors.5

In other words, noni had an inhibitory effect on new capillary formation.5 One of these trials used 34 samples of human breast cancer tissue; 17 were kept as controls and 17 were treated with noni. The treatment group showed complete blockage of new capillary growth and degradation of existing capillary networks after 14 days, compared with a sixfold increase in capillary growth in the control group.5 Theoretically, this may indicate that noni prevents tumor growth by preventing development of a supporting vascular network.

Another significant study demonstrated an impressive analgesic effect. Though not a human trial, this chemical assay study compared the analgesic effect of noni to aspirin and celecoxib (Celebrex).6 It was found that the COX-2 inhibitory effect of noni was comparable to that of celecoxib and that the COX-1 inhibitory effect of noni exceeded that of aspirin by 41%.6

Safety and side effects
Because noni is a botanical substance, allergic reactions are always a potential hazard. The most notable adverse effect is hepatotoxicity, with multiple cases documented in the literature.2 The effects included significant elevations in liver enzymes.1 In all cases, however, the adverse effects resolved completely, without sequelae, after the patients stopped using noni.1

Anyone taking ACE inhibitors or potassium-sparing diuretics for hypertension should be cautious of noni because these drugs tend to increase serum potassium and noni is already a rich source of this electrolyte.2 Though rare, hyperkalemia is possible, which would make this supplement a poor choice for those with renal insufficiency.

Noni is not considered safe for small children or pregnant or lactating women. Noni also antagonizes warfarin (Coumadin) due to its high vitamin K content.

Dose and price

Most often marketed as a juice, noni can also be purchased as dried fruit or powder-filled capsules. The recommended dose is 2 oz once or twice a day for two to three months.2 Continuous use is not recommended.
Noni can be fairly expensive. A one-month supply of juice at the recommended dose costs $40-$50.

Summary

Noni probably should not be a pantry staple, even for patients unlikely to have adverse reactions. It is costly and carries the risk of some significant side effects and drug interactions.

However, the many potential benefits of noni  make it very intriguing and worthy of further investigation. For a person without the drug- or disease-interaction potentials, periodic use of this supplement could prove to be a useful addition to the antioxidant arsenal.

References

1. Natural Medicines Comprehensive Database (2008). Noni. Stockton, Calif.: Therapeutic Research Faculty.
2. Natural Standard Monograph (2008). Natural Medicines Comprehensive Database . Natural Standard, Inc.
3.Herbs at a glance. Noni. National Center for Complementary and Alternative Medicine.
4. Wang MY, West BJ, Jensen CJ, et al. Morinda citrifolia (Noni): a literature review and recent advances in Noni research. Acta Pharmacol Sin. 2002;23:1127-1141.
5. Hornick CA, Myers A, Sadowska-Krowicka H, et al. Inhibition of angiogenic initiation and disruption of newly established human vascular networks by juice from Morinda citrifolia (noni). Angiogenesis. 2003;6:143-149.
6. Li RW, Myers SP, Leach DN, et al. A cross-cultural study: anti-inflammatory activity of Australian and Chinese plants. J Ethnopharmacol. 2003;85:25-32.

All electronic documents accessed April 3, 2008