Milk Thistle (Silybum marianum)

Milk thistle (Silybum marianum) is a flowering plant native to the Mediterranean and parts of Europe and Asia. Its seeds contain a flavonoid complex called silymarin, which is the primary active ingredient used in dietary-supplement form for supporting liver health and antioxidant protection. The herb has been used for centuries as a “liver-protective” agent, and modern research focuses on its hepatoprotective, anti-inflammatory, and antioxidant properties.

• Composition: Silymarin is a mixture of flavonolignans; the most studied component is silybin (also called silibinin), a dihydroflavonol with a 1-phenyl-2-hydroxy-3-(4-hydroxy-3-methoxy-phenyl)-propen-1-one structure.
• Molecular Formula: The molecular formula of silybin A is C₂₅H₂₂O₁₀ (IUPAC: (2S,4R)-2-(4-hydroxy-3-methoxy-phenyl)-3-[2-(4-hydroxy-3-methoxy-phenyl)-2-oxo-2-(2-hydroxy-2-methylpropyl)-1-phenylpropyl]-2-hydroxy-4-(p-hydroxy-phenyl)-3-hydroxy-1-propen-1-one).
• Key Features:
  • A catechol moiety (ortho-dihydroxy phenyl) that confers strong radical-scavenging activity.
  • A lactone ring that contributes to membrane-stabilizing properties.
• Antioxidant Capacity: The flavonolignan composition (silybin A/B ≈ 50 % of silymarin) determines the antioxidant capacity.
• Phytosome Technology: The “silybin-phosphatidylcholine complex” (phytosome) improves lipophilicity and intestinal absorption (up to 7-fold increase versus standard extract).

• Cultivation: Milk thistle is cultivated worldwide, with major commercial cultivation in Italy, Spain, and the United States (California).
• Processing: Seeds are harvested, dried, and milled to a fine powder.
• Extraction:
  • The standard method uses ethanol or methanol–water mixtures (70 % ethanol) under controlled temperature to yield a 70-80 % silymarin extract.
  • Super-critical CO₂ extraction is increasingly used for higher purity and lower solvent residues.
• Phytosome Production: Phytosome technology (silybin-phosphatidylcholine) is produced by complexing silybin with soy or sunflower phosphatidylcholine under high-shear mixing.
• Quality Standards:
  • Require a minimum of 70 % silymarin content.
  • Low heavy-metal levels (< 10 ppb lead).
  • Absence of pesticide residues.
• Product Preferences: Certified organic, GMP-certified, and third-party tested products are preferred to ensure batch-to-batch consistency and safety.