017 Silybum marianum (L.) Gaertner
Nome comune: Cardo di S. Maria, Cadro mariano, cardo lattario
Silybum marianum is a milk thistle, is an annual or biannual plant of the Asteraceae family. This fairly typical thistle has red to purple flowers and shiny pale green leaves with white veins. Originally a native of Southern Europe through to Asia, it is now found throughout the world. The medicinal parts of the plant are the ripe seeds.
Common names for this species include blessed milk thistle, Marian Thistle, Mary Thistle, St Mary's Thistle, Mediterranean Milk Thistle and Variegated Thistle.
It grows 40 to 100 cm tall. The stem is grooved and more or less cottony.
The leaves are oblong to lanceolate. They are either wavy loved or pinnated, have spiny edges. They are hairless, shiny green, with milk white veins.
The flower heads are 4 to 5 cm long and wide, of red-purple colour. They flower from June to August.
The bracts are hairless, with triangular, spine-edged appendages, tipped with a stout yellow spine.
The achenes are black, with simple long white pappus, surrounded by a yellow basal ring.
In herbalism, it is used in cases of liver diseases (cirrhosis, jaundice and hepatitis), gallbladder disease, and is claimed to protect the liver against poisons. Silibinin (syn. silybin, sylimarin I) is a hepatoprotective (antihepatotoxic), antioxidant (radical-scavenging agent), thus stabilizing and protecting the membrane lipids of the hepatocytes (liver cells). Silicristin inhibits the enzymes peroxidase and lipoxygenase. Silidianin is a plant growth regulator. A 2000 study of such claims by the AHRQ concluded that "clinical efficacy of milk thistle is not clearly established". However a more recent study did show activity against liver cancers. A 2005 Cochrane Review considered thirteen randomised clinical trials which assessed milk thistle in 915 patients with alcoholic and/or hepatitis B or C virus liver diseases. They question the beneficial effects of milk thistle for patients with alcoholic and/or hepatitis B or C virus liver diseases and highlight the lack of high-quality evidence to support this intervention. Cochrane concluded more good quality randomised clinical trials on milk thistle versus placebo are needed.
Its potent extract is used in medicine under the name silymarin (a flavonolignane complex consisting of silibinin A and B/silybin/silymarin I, isosilibinin A and B, silicristin/silymarin II, silidianin). Silibinin is used against poisoning by amanitas, such as the Death Cap (Amanita phalloides) as well as in cerebral edema and acute hepatitis therapy.
Mary thistle has been grown as a medicinal plant in monasterial gardens since ancient times.
Possibly native near the coast of south east England.It has been widely introduced outside its natural range, for example into North America, Australia, and New Zealand where it is considered an invasive weed. Cultivated fields for the production of raw-material for the pharmaceutical industry exists in bigger dimension in Austria (Region Waldviertel), Germany, Hungary, Poland, China and Argentina. In Europe it is sown yearly in March-April. The harvest in 2 steps (cutting and threshing) takes place in August, about 2–3 weeks after the flowering.
Due to potassium nitrate content, the plant has been found to be toxic to cattle and sheep. When potassium nitrate is eaten by ruminants, the bacteria in animal's stomach breaks the chemical down, producing a nitrite ion. Nitrite ion then combines with hemoglobin to produce methaemoglobin, blocking the transport of oxygen. The result is a form of oxygen deprivation. 
The extract is now also being used in a beverage called Rockstar Energy Drink as an energy enhancing agent.