EFSA Confirms Safety of Noni Leaves for Tea

The tropical Morinda citrifolia or noni plant is classed as a novel food under the Novel Food Regulation, which covers foods that do not have a long history of consumption in the EU.

12/08/08 The European Food Safety Authority's (EFSA) NDA Panel has confirmed the safety of dried roasted noni leaves for making tea infusions at the expected intake levels.

The tropical Morinda citrifolia or noni plant is classed as a novel food under the Novel Food Regulation, which covers foods that do not have a long history of consumption in the EU even if widely consumed in other parts of the world. Derived food or drink products from noni require authorisation. A food manufacturer has submitted an application to market dried and roasted noni leaves and the Commission asked EFSA to evaluate the evidence on its safety, including scientific issues raised by Member States during the regulatory commenting period.

In order to estimate potential intake levels, the Panel used reported figures for tea consumption in the UK National Diet and Nutrition Surveys. The Panel concluded that, on the basis of the whole set of data and information provided by the applicant, the use of dried and roasted noni leaves for the preparation of infusions is safe at the anticipated intake levels.

The Panel however noted the current limitations on assessing and predicting the allergenicity of foods and the difficulties of using data from animal models to predict human allergenicity.

EFSA has previously assessed the safety of noni fruit juice, following a request from the European Commission in 2006. EFSA particularly examined the possibility that consumption of noni juice could cause adverse liver effects following four case reports in Austria. The NDA Panel found there was no convincing evidence for a causal relationship between the reported health problems and the consumption of noni juice.

EFSA noted that after cutting, the leaves of M. citrifolia are subjected to drying and roasting steps. The steps are standard procedures commonly applied in food production and do not give rise to concern. Compositional data on various batches of dried and roasted M. citrifolia leaves from French Polynesia have been provided. The information presented does not indicate detrimental nutritional effects to be expected from the consumption of tea infusions made from dried and roasted M. citrifolia leaves. Under the applied analytical conditions none of the anthraquinones rubiadin, alizarin and lucidin could be detected in dried and roasted M. citrifolia leaves (detection limits 0.25, 0.025 and 0.4 mg/kg) and in infusions (detection limits 1.04, 0.1 and 1.67 µg/l), respectively. 5,15-Dimethylmorindol, an anthraquinone previously isolated from the fruits of M. citrifolia, was shown to be present in dried and roasted M. citrifolia leaves at concentrations ranging from 11.3 to 42.6 mg/kg. In infusions from dried and roasted M. citrifolia leaves contents of 5,15-dimethylmorindol ranging between 5.8 and 20.9 µg/l were determined. On the basis of an average 5,15-dimethylmorindol content of 26.5 ± 11.75 mg/kg in dried and roasted leaves and an average extraction efficiency of 34 %, a total of approximately 9 ± 4 μg 5,15-dimethylmorindol is expected to be present per cup of tea (100 ml). Roasting of M. citrifolia leaves causes 80 and 77 % decreases of the concentrations of the glycosides rutin and kaempferol-3-O-α-L-rhamnopyranoysyl-(1-6)-ß-D-glucopyranoside, respectively, and 2- and 2.9-fold increases of the corresponding aglycones, quercetin and kaempferol, due to degradation of their glycosidic precursors.

Intake values reported for tea in the U.K National Diet and Nutrition Surveys were used to estimate the potential intakes of infusions prepared from dried and roasted M. citrifolia leaves. According to the applicant, infusions are prepared by steeping roasted M. citrifolia leaves (1 g in a tea bag) in 240 ml of hot water at 100 ± 2° C for ten minutes. Applying the total solids content of 0.1 % to the estimated 97.5th percentile intakes of infusion reveals that the highest ingestion of M. citrifolia leaf material is 1.29 g/d for adult males. This corresponds to a daily intake of 18.4 mg/kg bodyweight (bw), for a 70 kg adult. Applying the same approach to children reveals that the highest ingestion (97.5th percentile) of M. citrifolia leaf material is 11.5 mg/kg bw for 15 to 18 year old males, assuming a body weight of 60 kg.

Acute toxicity studies in rats using aqueous and ethanolic extracts did not give indications of adverse effects. In a subchronic (90-day) feeding study in rats with Tahitian Noni® Leaf Tea the no-observed adverse effect level was 2500 mg/kg bw/day, the highest dose administered.

Tests for gene mutations in bacterial cells (Ames test) gave positive results in one tester strain (TA 98) in the presence and absence of S-9 mix, when DMSO or ethanolic extracts of roasted M. citrifolia leaves were used. Aqueous extracts, the most appropriate type of extract with regard to the expected route of exposure, were tested negative in this assay. Tests for gene mutations in mammalian cells (HPRT test) using aqueous and ethanolic extracts were negative in the absence of S-9 mix, whereas the aqueous extract induced a slight increase in mutant frequency at two dose levels in the presence of S-9 mix. This equivocal result was outweighed by a clearly negative result in a second HPRT assay when a more concentrated aqueous extract was used. Tests on chromosome mutations in vitro and in vivo gave negative results. The Panel was satisfied with the total information provided, which allows the conclusion that consumption of infusions prepared from M. citrifolia leaves is not expected to induce genotoxic effects.

The Panel noted the current limitations to assess and to predict allergenicity of foods, such as infusions from dried and roasted M. citrifolia leaves, and was aware of the difficulties to use data from animal models for prediction of allergenicity in humans.

The Panel concluded that, on the basis of data provided, the use of dried and roasted M. citrifolia leaves for the preparation of infusions at the anticipated levels of intake is safe.