Analytische und toxikologische Untersuchungen von Früchten von Morinda citrifolia (English shop)

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Morinda citrifolia, also known in Hawai’i and in Europe under the name Noni, is a medicinal plant that has been used for more than 2000 years in the Polynesian and Indonesian cultural sphere, where it constitutes a folk medicine. Traditionally, all parts of the plant, such as leaves, roots, flowers and fruits, were used against a wide variety of ailments. Since 1996, products derived from the plant M. citrifolia have been permitted on the US market as well as in Canada, Japan, Australia, Mexico, Norway and Hong Kong. In 2003, the juice of the fruits was authorised in the EU as a novel food for use in pasteurised fruit juice beverages. Since August 2008 the dried and roasted leaves for the preparation of tea-like beverages, and since April 2010 additionally fruit juice concentrate and fruit puree, have been authorised in the EU.

The juice, however, represents the most frequently consumed product from M. citrifolia in the EU. Although the prices are unusually high for an ordinary fruit juice, quite a number of consumers are willing to pay them. This may be due to the fact that Noni products are often advertised with positive health effects, such as healing-promoting effects in cancer, cardiovascular diseases as well as in infections, allergies and other deficiencies of the immune system. Although some studies concerning positive properties of Noni exist, the majority of these postulated effects has so far lacked any scientific basis.

Numerous publications on the constituents of the plant M. citrifolia, in particular of the fruits, exist to date. However, little is known about the qualitative and quantitative composition of the juices obtained from them. One aim of this work is therefore to provide an overview of the volatile and non-volatile compounds in fermented and fresh juices. For subsequent quantitative analyses, the isolation and structure elucidation of relevant constituents is necessary, since standard substances are in most cases not commercially available. The isolation of compounds is to start from various fruit juice extracts. Enrichment is carried out by means of countercurrent chromatography and further purification to obtain pure substances by means of preparative HPLC or size exclusion chromatography. The structure elucidation of the isolated substances is performed with 1D and 2D NMR spectroscopy and high-resolution mass spectrometry. In addition, these investigations are to be extended to the other components of the fruit, such as pulp and stones, as no data are available on these up to this point.

Among the described positive effects of fruit juices of M. citrifolia are their antioxidant properties. The antioxidant potential as well as the total phenolic content of the juices associated with it, as well as the extracts prepared from them, are therefore to be investigated in more detail.

However, there are also negative headlines in connection with Noni. Several cases in which liver damage occurred after the consumption of Noni products have been published. According to the assessment of the Scientific Committee on Food (SCF), however, there is no causal relationship between hepatotoxicity and the intake of Noni products. In order to shed more light on this question, the cytotoxic properties of Noni juices and their extracts are examined by means of the brine shrimp assay and the resazurin (Alamar Blue) assay on rat hepatocytes in primary culture.

The high prices mentioned above make the adulteration of Noni juices appear very lucrative. Therefore, the knowledge gained about the characteristic compositions of the volatile and non-volatile constituents of the juices is to lead into approaches for the authentication of such products. In this context, particular attention is to be paid to the two different production processes for Noni juices. These are offered on the market as fermented or fresh juices. The traditional Polynesian process leads to fermented juices and is considerably more elaborate in contrast to the production of freshly pressed juice. Since a reliable method for distinguishing the two Noni juice products has not been possible to date, approaches for the unambiguous assignment of both products are to be presented here.

https://www.tu-braunschweig.de/ilc/forschung/akw/mitarbeiter/ehemalige/stolle