Milk thistle (also known as blessed milk thistle, Marian thistle, Saint Mary's thistle, Mediterranean milk thistle, variegated thistle, or Scotch thistle) is one of the best remedies for liver ailments in the Western herbal medicine. Botanically known as Silybum marianum, it belongs to the sunflower family (Asteraceae). The genus name Silybum is derived from the Greek word silybon for some thistle-like plant and the specific epithet applies to plants with mottled leaves. Due to its mottled leaves with white areas around the veins, it is called as dudhpattra in Dogri language.
DISTRIBUTION
Milk thistle is a native to the much of Europe, Central Asia, and India. It was introduced as a medicinal herb in many countries such as North America, Hawaii, Australia, New Zealand, and Colombia. However, it has naturalised in many parts of the world outside it natural range and become a highly invasive weed there. More recently, it has widely spread in many parts of Himachal Pradesh as an obnoxious weed.
MORPHOLOGY
Milk thistle is an upright herbaceous annual or biennial that can grow to a height of up to 2 m with nearly conical canopy architecture. The stem is shallowly grooved and is covered with fine cottony fuzz. The leaves are up to 60 cm long, pinnately lobed, and have spiny edges like in most of the thistles. The leaves are shiny pale green with milky white veins which gives it a name ‘milk thistle.’ The inflorescence is a red-purple coloured capitulum (head) up to 12 cm in size. The flower head is surround by large-sized triangular bracts terminating into a sharp spine. The fruits are black-coloured achenes with white pappus that acts as a parachute for long distance seed dispersal by wind.
CHEMICAL CONSTITUENTS
Milk thistle seeds chiefly contain polyphenolic flavonolignans. Seven closely related flavonolignans (silybin A, silybin B, isosilybin A, isosilybin B, silychristin, isosilychristin, silydianin) which are collectively known as silymarin, are principal bioactive constituents in milk thistle. Taxifolin (flavonoid), betaine, apigenin and silybonol also occur in the seeds.
MEDICINAL USES
Milk thistle has been used in the western countries for more than 2,000 years as an herbal treatment for liver and kidney ailments. The medicinal uses of milk thistle are discussed below:
1. Hepatoprotective Function
Milk thistle seeds are reported to have hepatoprotective and antioxidant properties. It recommended in complimentary western herbal medicine to restore the normal liver parameters.
2. Remedy for Liver Disease
Milk thistle is widely used for treating liver degenerative necrosis, hepatitis, and cirrhosis. It can help in repairing liver by growing new cells. It is often recommended to treating liver conditions associated with alcohol damage.
3. Useful in Viral Hepatitis
Milk thistle is recommended for the treatment of viral hepatitis especially hepatitis C.
4. Antidote to Mushroom Poisoning
Milk thistle is used as an antidote to poisoning caused by death cap mushroom (Amanita phalloides). It is reported to counteract the harmful effects of toxins like amatoxin present in poisonous mushrooms and significantly reduces the risk of liver damage and death in animal models.
5. Anti-Cancer Properties
Silymarin present in seeds of milk thistle is reported to have anti-cancer properties in lab studies. It is reported to inhibit cell division in cancer cells and to reduce blood supply to tumours.
6. Useful in Diabetes
Some reports consider milk thistle useful in lowering blood sugar level in with type 2 diabetes. A recent study on animal model has shown that milk thistle can help to reduce insulin resistance in people with type 2 diabetes.
7. Good for Skin Health
Research on animal models have shown that milk thistle oil helps to improve inflammatory skin conditions when applied topically. It has antioxidant and anti-aging effects on human skin cells in a laboratory environment.
8. Reduces Cholesterol
Some researchers have reported that milk thistle can lower blood cholesterol levels and is good for heart health.
9. Improves Asthma Symptoms
Various studies on animal models have shown that silymarin present in milk thistle seeds helps to protect against inflammation in the airways of mice with allergic asthma by regulating immune responses.
10. Improves Cognition
Milk thistle is reported to increase resistance to oxidative stress in animal studies. Oxidative stress is a major cause of degenerative conditions and Alzheimer’s disease. However, more research is required to prove its benefits on human beings.
CAUTION
Milk thistle seeds are highly prone to fungal infestation and may accumulate high concentration of mycotoxins. Mycotoxins are harmful to human beings. Milk thistle is reported to be toxic to cattle due to the presence of potassium nitrate. Bacteria living in the stomach of ruminants break down this chemical and produce nitrite ions which later combine with haemoglobin and block the transport of oxygen.
