Morinda citrifolia L. (noni) is a tropical plant that has been used for centuries in traditional medicine for numerous purposes and, nowadays, is largely commercialised on the worldwide market as a dietary supplement. Long-term in vitro cultures of Helianthus tuberosus dormant parenchyma explants constitute a classical growth model that can be used to evaluate the proliferative or antiproliferative and/or cytotoxic effects of different mixtures of chemicals present in food or with putative pharmacological applications. Explants of dormant tubers were cultured in vitro with 2%, 10% and 20% (v/v) of noni fruit juice. After four weeks of culture, explant cell growth was reduced 40.5%, 72.5% and 73.9%, respectively, by 2%, 10% and 20% (v/v) of noni juice in comparison to untreated controls. Our results demonstrated that noni fruit juice possesses strong antiproliferative capacity, low cytotoxicity and moderate antioxidant activity. © 2013 © 2013 Società Botanica Italiana.