J Sci Food Agri. 2007 November; 87(14): 2583-2588.
Safety tests and antinutrient analyses of noni (Morinda citrifolia L.) leaf.
West BJ, Tani H, Palu AK, Tolson CB, Jensen CJ.

Noni (Morinda citrifolia L.) leaves have a documented history of food use. However, previous safety and antinutrient studies are absent. The current investigation was conducted to assess the utility of noni leaves as food. RESULTS: No evidence of toxicity or differences in weight gain were observed in acute, subacute, and subchronic oral toxicity tests of ethanol–water (1:1 v/v) and hot-water extracts of noni leaves in mice at doses of 2000, 200, and 20 mg kg−1 body weight, respectively. Acute systemic anaphylaxis tests of the ethanol–water (4:1 v/v) and hot-water extracts were negative. Further, leaf proteins were readily digested in simulated gastric fluid. Tannic acid concentrations in frozen and dried leaf were 1.6 and 25.8 g kg−1, respectively. Phytic acid was not detected in the raw leaf (<1g kg−1). The average oxalic acid content was 1 g kg−1 and was fairly uniform among 22 leaf samples from 11 islands throughout French Polynesia. Similarly, campesterol, stigmasterol, and β-sitosterol content did not vary widely, suggesting low inter-island content variability. The apparent lack of toxicity of the leaves and the hardiness of the plant make it ideal for further agricultural development, especially where sustained growth of other food crops is difficult.