Comparative evaluation of flavonoid content in assessing quality of wild and cultivated vegetables for human consumption

BACKGROUND: Owing to the demand for 'health foods', commercial development of wild vegetables may find a sizable market niche if adequate agricultural methods are used to domesticate such species. Available techniques of cultivation (even in traditional farming) may provide many advantages, such as enhancement of the content of active principles in plants and improvement in the quality of the raw material to be processed on an industrial scale. In this context, the flavonoid composition and content of roots and leaves from five varieties of wild herbs (Cichorium intybus, Portulaca oleracea, Tragopogon porrifolius, Urtica dioica and Valerianella eriocarpa) and their cultivated relatives in central Italy were compared. The aims of the study were (i) to reveal the metabolic profile of particular bioactive metabolites present in some unusual food species by using a simple method of analysis, (ii) to quantify and compare the amount of polyphenolic metabolites in wild and cultivated plants and (iii) to evaluate the effect of growing conditions on polyphenolic variability. Data were subjected to statistical analysis.