Silymarin and Fatty Acid Profiles of Milk Thistle (Silybum marianum L.) Genotypes

Milk thistle (Silybum marianum L.) seeds are known for their high amounts of bioactive silymarin complex and oil, both contributing to its potential as a functional food. This study aimed to evaluate the phytochemical composition of four milk thistle varieties (Silma, Silyb, Mirel, and Moravia 55), focusing on the silymarin complex, oil yield, and fatty acid profile. Silymarin content was quantified by high-performance liquid chromatography with diode-array detection (HPLC-DAD) following ultrasound-assisted extraction (USE). Pressurized liquid extraction (PLE) was employed for determining oil yield, and the fatty acid composition was performed by gas chromatography with flame ionization detection (GC-FID). Results showed significant variability between genotypes. The total silymarin content ranged from 12.69 to 20.28 mg·g⁻¹ DW, with silychristin, silybin A, and silybin B as major constituents. Oil content varied from 22.81 to 26.25%, with Mirel 2 showing the highest yield. Fatty acid analysis revealed a high proportion of unsaturated fatty acids (79.30-83.30%), with linoleic (53.53-62.27%) and oleic (20.17-24.57%) acids being the most abundant. The results were further evaluated by Principal Component Analysis and hierarchical cluster analysis. The study's findings may contribute to the strategic selection of milk thistle genotypes for pharmaceutical or nutritional applications, and support targeted cultivation to optimize phytochemical content.