Silybum marianum (L.) Gaertn. – Milk thistle

Silybum marianum is herbaceous, annual medicinal plant in Asteraceae family / Carduoideae subfamily (Th). Milk thistle has taproot, the stem is erect, often branched 1.5-2.5 m tall. The stark leaves stand in a big leaf rosette, they are stalkless, oblong-elliptic, pinnatifid, the margins are thorny. The leaf surface is hairless, shiny with milk-white veins. The flower heads are 5-8 cm wide, ovate, thorny, purple or sometimes white colour. The flowering time lasts from June to July. Milk thistle’s fruit is oblong-ovate, brown achne with topknot on it. Thousand seed weight: 22-31 g.

Originally Silybum marianum is native to South Mediterranean, now it is distributed throughout the world. In Central Europe and Hungary, the plant is also intensively cultivated. Milk thistle prefers warm, sunny places, grows well on almost every soil types.

The ripe fruit (Silybi mariani fructus) of milk thistle is described in Hungarian Pharmacopoeia VIII. ESCOP- and E-monographs also mention the drug as Cardui mariae fructus (Milk Thistle Fruit). The standards require at least 1.5 % silybinin (silybin) in the fruits.

The therapeutic effect of milk thistle is caused by the flavonolignanes of the fruit pericarp. This substances occur in 1.5-3.0 %, and known as silymarin complex (silybinin, silydianin, silychristin). The drug contains flavonoids (taxifolin, quercetin, kaempferol, apigenin), fatty oil (20-25 %), sterols, mucus too.

The active substances of Silybum have anti-inflammatory, antioxidant, radical-scavenging, hepatoprotective activity. The mebrane lipid stabilisation effect is also proved. It is used in cases of liver diseases (cirrhosis, hepatitis) and claimed to protect the liver against poisons. In folk medicine it was used for healing jaundrice and increase lactation.