Natural Remedies A-Z
Milk thistle |
Milk Thistle (Silybum marianum) is becoming a very widely used herb these days, and has recieved considerable press. It is most famously used as a liver remedy, but was traditionally used to promote milk flow in breast feeding mothers - hence its name! This spikey biennial grows up to 1 meter in height and is topped by a rugged pinky flower. The leaves have a distinctive white mottling along the veins.
Constituents
Flavolignans: silymarin
Flavanoids: quercetin, taxifolin, dehydrokaempferol
Lipids: linoleic acid, oleic acid, palmitic acid
Antioxidant action
Part of milk thistle’s protective action is due to its antioxidant capabilities. Silymarin is a potent antioxidant that reportedly inhibits lipid peroxidation (Barnes et al 2002:342). It has also been shown to increase levels of glutahione in the liver (2002:342), which is part of the body’s own antioxidant systems, and a detoxifier to boot.
As free radicals play a significant role in the pathogenesis of many liver disorders, it is believed that the antioxidant activity of this herb contributes greatly to its hepatoprotective action.
Hepatoprotective and hepatorestorative actions
Milk thistle has shown time and time again to be astoundingly protective against liver damage following exposure from a wide range of toxic substances including alcohol. One double blind placebo-controlled trial consisting of 33 patients suffering with toxic liver damage, the group taking milk thistle extract showed greatly improved levels of ALT and AST levels (markers of hepatocyte damage)(Boon & Smith 2004:216). This activity maybe in part due to a point raised previously. This is the increase in glutathione levels in the liver. Glutathione is a potent antioxidant that transforms and detoxifies a wide range of harmful chemicals. Silymarin also displays a competitive binding activity with some toxins, thus disarming them.
Another property of milk thistle is as a hepatoregenerative action. This action is belived to arise again from silymarin. It seems to cause a stimulation of DNA polymerase A. Stimulation of this enzyme increases the synthesis of ribosome proteins thus stimulating cell development and regeneration (2004:216).
Use in cancer
There has been some interesting research on the impact of milk thistle upon cancerous cells. Although one must note that these studies have been conducted in vitro. Studies showed an inhibition in growth of Human ovarian and breast cancer cells, and also showed a synergistic action with the antineoplastic drug cisplatin (Bone 2003:327). A similar action has been shown on isolated prostate tumour cells, where an inhibition in a specific growth factor was inhibited (Barnes et al 2002:343). It must remain in mind that these studies were all conducted in vitro and therefore may not represent things that would occur within the body.
References
Barnes J, Anderson LA, Phillipson JD (2002). Herbel Medicines (2nd ed). UK,London: Pharmaceutical Press).
Bone K (2003). Clinical guide to blending liquid herbs. Churchill Livingstone.
Boon H, Smith M (2004). The 50 most common medicinal herbs. Canada, Toronto: Robert Rose Inc.