Variation in Phenolic Composition of Knautia arvensis in Correlation with Geographic Area and Plant Organ.

Knautia arvensis (family Dipsacaceae) is usually found in grasslands of Europe, but can also be found in some parts of Africa and Asia, usually in dry meadows, pastures, dry hills, and open woods. The chemical composition of this species is relatively unknown. The aim of this study was to give a phenolic profile of this plant, and to show how its phenolic composition varies depending upon plant organ and geographic origin. The chemical analysis included quantification of free phenolics soluble in methanol, esters and glycosides, and phenolics that are insoluble in methanol. Fourteen different phenolic acids and eight flavonoids were quantified in total. According to this study, the chemical composition of individual plant parts can differ tremendously within one population, which does not have to be in correspondence with chemical variability between populations. As shown in this study, the variation in chemical composition between plant parts can exceed that between different populations (from different climates, altitudes, with different environmental factors), which implies that microhabitat conditions can greatly affect the composition of some plant parts, which was shown also after PCA and HCA analysis.