Profile of Selected Secondary Metabolites and Antioxidant Activity of Valerian and Lovage Grown in Organic and Low-Input Conventional System

In the present study, the roots of valerian (Valeriana officinalis L.) and lovage (Levisticum officinale Koch.) from the organic and low-input conventional cultivation systems were subjected to the analysis of selected groups of phenolic compounds (phenolic acids, flavonoids) and antioxidant activity. Plants were grown in two consecutive vegetation seasons in the experimental plots located in western Poland. Phenolic acids and flavonoids were determined by high performance liquid chromatography (HPLC/UV-Vis), while the antioxidant activity of the samples was measured with the use of DPPH radical scavenging activity assay. The concentrations of phenolic acids (sum) and flavonoids (sum) were found to be higher in the conventional lovage roots, as compared to the organically grown lovage roots, while in the case of valerian, no significant effects of the cultivation system on the levels of the sums of these analyzed compounds were found. Furthermore, no significant effect of the cultivation system on the antioxidant activity of herbs was observed. Additional efforts could be invested in enhancing the potential of organic medicinal plants to consistently present the expected high concentrations of health-promoting antioxidants, which could be effectively brought through their post-harvest handling, storage and processing, and thus meet consumers' expectations at the stage when they reach the market.