Effect of Field Trial on Silymarin Complex Composition and Antioxidant Assessment of Milk Thistle (Silybum marianum L. Gaertner).

Plant foods are receiving increasing attention as a valuable source of health beneficial compounds. Understanding the impact of growing conditions on the quality of milk thistle is critical for determining appropriate agro-ecological and agro-economic parameters for its production and, subsequently, food products rich in health-beneficial compounds. For this purpose, a randomized milk thistle cultivation trial was established in the experimental field of Agritec Plant Research Plc. in Šumperk, Czech Republic, and carried out for two subsequent growing seasons in 2020 and 2021. The milk thistle achenes, variety Mirel, were sown in the row width of 12.5, 25 and 37 cm; and the qualitative parameters of each field trial such as achenes yields, silymarin complex determination and also antioxidant assessment (total phenolic content, total flavonoids content, DPPH and ABTS radical scavenging activity) were evaluated. The environmental impact of the extraction process was reduced by using pressurized liquid extraction with 60% EtOH (v/v). The weather conditions during the trial as well as the row spacing of milk thistle sowing were revealed to have a significant influence on the evaluated parameters (p ≤ 0.05). The highest yields of evaluated parameters were obtained for the growing season 2021 and the row spacing of 37 cm.