Molecular pattern of Chinese artichoke (Stachys affinis Bunge)

Stachys affinis Bunge, also known with the common name of Chinese artichoke, is a perennial herbaceous plant belonging to the Lamiaceae family. This species is mainly known for its tubers which are used in gastronomy as root vegetables in several parts of the world comprising its origin area (Eastern Asia) as well as Europe where it is now fairly cultivated. In this work, we report the profile of S. affinis tubers, collected in December, 2014 in the town of Gazoldo degli Ippoliti, province of Mantova (geographic coordinates: 45°11'25" N, 10°34'40" E) at an altitude of 35 m a.s.l. where it was cultivated. We investigated both primary and secondary metabolites using HPLC and GC both coupled with MS for the study of the primary metabolites and CC, NMR and ESI-MS for separation and identification of the secondary metabolites, respectively. Primary metabolite pattern is composed by carbohydrates, proteins, fibers and fatty acids while secondary metabolite pattern is mainly constituted by phenyl-ethanoid glycosides (PhGs) and iridoids. The secondary pattern is in agreement with the botanical classification having found the typical compounds of the genus. Yet, it is also noteworthy to mention the important contribution that all the primary metabolites give to the nutritional properties of the rhizomes providing a rationale for their traditional culinary use, then. Moreover, PhGs and iridoids, that are endowed with interesting biological activities 4,5, ascribe functional properties to this food and might also contritube to the characteristic bitter-sweet taste of the tubers.