Flavonoids classification

It was concluded from the data that flavonoid patterns are systematically informative at the infrageneric level and may facilitate the taxonomic classification of these types of plant species [155],... 

Cos, P. et al., Structure-activity relationship and classification of flavonoids as inhibitors of xanthine oxidase and superoxide scavengers, J. Nat. Prod., 61, 71, 1998. 

Williams, C.A., Greenham, J., and Harbome, J.B., The role of lipophilic and polar flavonoids in the classification of temperate members of the Anthemideae, Biochem. Syst. Ecol., 29, 929, 2001. 

Williams, C.A. et al., Flavonoid patterns and the revised classification of Australian Restionaceae,... 

Hegnauer, R. and Grayer-Barkmeijer, R.J., Relevance of seed polysaccharides and flavonoids for the classification of the Leguminosae a chemotaxonomic approach. Phytochemistry, 34, 3, 1993. 

SM Lunte. Structural classification of flavonoids in beverages by liquid chromatoaphy with ultraviolet-visible and electrochemical detection. J Chromatogr 384 371-382, 1987. 

There is growing evidence from human feeding studies that the absorption and bioavailability and thus bioactivity of phenolic compounds and flavonoids are very much dependent on the nature of their chemical structure. Their chemical classification and dietary occurrence is briefly discussed in the following section. 

Further systematic classification at the level of families and subfamilies using the patterns of betalains is possible only in a few cases (see below). The majority of chemotaxonomic work on members of the Caryophyllales has been concentrated on flavonoids (101). More investigations, especially on the basis of sound phytochemical work as well as extensive screening data, for example, with the aid of HPLC, are needed. Table I summarizes the distribution of betalains in the Caryophyllales (only well-characterized compounds are listed). 

Tanacetum species contain mainly sesquiterpenoids and flavonoids, whereas the other terpenoids and phenolic compounds are rarely found. Sesquiterpenoids which are the main constituents of the genus, supposed to be bioactive principles of the plants. Flavonoids and essential oils are also pointed out as active substances in some species. On the other hand, there is a confusion on the systematic position and classification of several species of Asteraceae, therefore chemotaxonomy of the species will help the systematic studies. 

One more widely known classification of flavonoids consists of two main groups, namely flavonoids (in the narrow sense) and isoflavonoids, the first with a C6-C3-C6 skeleton based on 1, 3-diphenylpropane and the latter based on 1, 2-diphenylpropane. So, flavonoids include the above mentioned subclasses (except isoflavones) and other groups such as chalcones, and the isoflavonoid group principally include isoflavones. 

Whereas LC-MS has been applied in the detection and characterization of other plant natnral prodnets, it was decided to foens on plant phenols, especially flavonoids. A general classification of plant phenols is given in Table 15.1. The application of MS to plant phenol characterization was reviewed [1]. 

Williams, C. A. Harbome, J. B. De Menezes, N. L., The utility of leaf flavonoids as taxonomic markers in the subfamily and generic classification of the Velloziaceae, Biochem. Syst EcoL, 1991, 19, 483-495. 

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