by Krista Molien
In a recent review article published in Phytomedicine, the author presents compelling evidence for the use of globe artichoke leaf extract (Cynara scolymus L., Asteraceae) in high cholesterol, dyspepsia (indigestion), and for liver protective effects (Kraft, 1997). A variety of clinical, in vitro, and in vivo studies on artichoke all confirm these traditional uses. In addition, researchers have identified some of the important constituents of the plant, including luteolin and the glycosides scolymoside and cynaroside.
Based on recent clinical studies with artichoke leaf, the author predicts that this plant will become a more common primary treatment for hypercholesterolemia (high cholesterol). In one multicenter study, 557 patients taking an average of 1.5 g of artichoke leaf extract daily experienced a significant decline in serum cholesterol and triglycerides over a 43-day period (Fintelmann and Menssen, 1995). Double-blind, placebo-controlled clinical studies as well as in vitro studies have also demonstrated artichoke extract's ability to increase healthful levels of high density lipoprotein (HDL) and to inhibit low density lipoprotein (LDL) oxidation. Researchers believe that artichoke leaf extract works by enhancing cholesterol elimination and reducing cholesterol synthesis in the liver. According to recent in vitro studies, the constituent luteolin has been found to inhibit cholesterol biosynthesis by up to 60 percent (Gebhardt, 1996).
A relative of milk thistle (Silybum marianum [L.] Gaertner, Asteraceae), artichoke leaf appears to offer similar liver protective and antioxidant benefits. In liver cell studies, 10 mg/ml artichoke extract protected liver cells from carbon tetrachloride toxicity (Recknagel and Glende, 1973). Treatment of liver cell cultures with 1 mg plant extract/ml incubation fluid inhibited harmful malondialdehyde production and cell death after exposure to coumen hydroperoxide and t-butylhydroperoxide (Gebhardt, 1996). Artichoke also appears to stimulate tissue regeneration, numbers of binucleate liver cells, RNA content, and cell division in liver cells pretreated with artichoke extract and then exposed to a variety of toxins in laboratory experiments. To date, these effects have not been confirmed in controlled clinical trials.
Artichoke leaf extract also has the ability to significantly increase the number and size of bile vesicles within the liver cells, which aids digestion (especially of fatty foods) by stimulating bile secretion. This was discovered recently during studies using liver cell cultures treated with 0.1 mg/ml artichoke leaf extract (Gebhardt, 1996). Several double-blind, placebo-controlled clinical studies have demonstrated the benefits of artichoke leaf extract in dyspepsia, a condition characterized by abdominal pain, heartburn, appetite loss, constipation, diarrhea, nausea, and other symptoms. Unfortunately, the review author failed to report the amount and type of artichoke extract used in these large-scale studies.
After review of the existing clinical research on artichoke, the author noted that the plant extract appeared to be well tolerated by 95 percent of all subjects. Contraindications for use include gall bladder or bile duct blockages. Although no allergic reactions have been reported, those with known sensitivities to Asteraceae (daisy family) plants should avoid artichoke leaf extract.
[Fintelmann V, Menssen HG. Recent results of research on artichoke leaf extract with lipid metabolism and dyspepsia [German]. Dtsch Apoth Ztg. 1996; 136: 1405.
Gebhardt R. Antioxidant and hepatoprotective effects of artichoke extracts and constituents in cultured rat hepatocytes. Internat Workshop on in vitro Toxicology. 1996; 6: 24-28.
Kraft K. Artichoke leaf extract -- Recent findings reflecting effects on lipid metabolism, liver, and gastrointestinal tracts. Phytomedicine. 1997; 4(4): 369-378.
Recknagel RO, Glende RA. Carbon tetrachloride hepatotoxicity: an example of lethal cleavage. Crit Rev Toxicol. 1973; 2: 263.]