This review investigated the relationship of noni juice, or its extract (fruit, leaves or root), to anticancer and/or immunostimulant properties. A Medline search was conducted using the key search words ‘Morinda citrifolia’ and ‘Morinda citrifolia and cancer’ (1964 to October, 2011) along with cross-referencing. Botanical and chemical indexes were not included. A total of 304 and 29 (10%) articles, respectively, were found under these key terms. Of the 19 studies actually related to cancer, seven publications were in vitro cancer studies, nine were in vivo animal cancer studies, and three were in vivo human cancer studies. Among the in vitro studies, a ‘concentrated component’ in noni juice and not pure noni juice may (1) stimulate the immune system to ‘possibly’ assist the body ﬁght the cancer, and (2) kill a small percentage (0–36%) of cancer cells depending on the type. The nine animal studies suggest that a concen-trated component in noni juice may stimulate the immune system; but only slightly increases the number (about 1/3; 25–45%) of surviving mice. Other than two case studies, only two human clinical studies existed. The ﬁrst consisted of testing freeze-dried noni fruit, which reduced pain perception, but did not reverse advanced cancer. The second was on smokers ingesting an unknown concentration of noni juice who experienced decreased aromatic DNA adducts, and decreased levels of plasma superoxide anion radicals and lipid hydroperoxide.
Factors to consider in the future are clearly deﬁning the substance being tested, and whether or not the juice is pasteurized. Some reports of hepatotoxicity exist, although there were confounding factors in most of the case reports. More importantly, noni juice is high in potassium and needs to be monitored by patients with kidney, liver or heart problems. In conclusion, a few in vitro and in vivo animal studies suggest a possible unidentiﬁed substance in unpasteurized noni fruit juice that may have a small degree of anticancer activity. The isolation of the active component warrants further research. Copyright © 2012 John Wiley & Sons, Ltd.