Globe artichoke: Background. Actions

Historical Note

Artichoke has a long history of use as a vegetable delicacy and medicinal agent, and its cultivation in Europe dates backto ancient Greece and Rome. Traditional use of artichoke has always pertained to the liver where it is considered to increase bile flow and act as a protective agent against various toxins. As such, it has been used for jaundice, dyspepsia, nausea, gout, pruritis and urinary stones. It is still a popular medicine in Europe today.

Common Name

Artichoke

Other Names

Alcachofa, artichaut, alcaucil, carciofo, cynara

Botanical Name / Family

Cynara scolymus L. (family [Compositae] Asteraceae)

Plant Part Used

Leaf

Chemical Components

Key constituents of the leaf include phenolic acids, mainly caffeic acid derivatives (e.g. chlorogenic acid), sesquiterpenes, lactones (e.g. cynaropicrin) and flavonoids (e.g. cynaroside, luteolin derivatives), phytosterols, inulin and free luteolin.

Main Actions

The main pharmacologically active constituents are thought to be the phenolic acids and flavonoids.

ANTIOXIDANT

Artichoke leaf extract exerts antioxidant effects, according to in vitro tests.

HEPATOPROTECTIVE

Improved hepatic regeneration, improved hepatic blood flow, increased hepatocyte counts, increased hepatic RNA concentrations and a stimulation of hepatic cytogen-esis have been associated with artichoke extract in animal studies.

Tests with primary hepatocyte cultures suggest that artichoke extracts have marked antioxidative and hepatoprotective potential.

CHOLERETIC AND CHOLAGOGUE

A significant increase in bile flow has been demonstrated in studies using isolated perfused rat liver in vivo after acute treatment, as well as after repeated administration. Choleretic activity has also been reported in a double-blind placebo controlled study, with maximal effects on mean bile secretion observed 60 minutes after a single dose.

A study that evaluated the effects of four extracts and phenolic content on bile flow and liver protection demonstrated that the extract with the highest concentration of phenolic derivatives exerted the strongest effect.

One study determined that treatment does not produce changes to the liver enzymes gamma-GT, AST, ALT or glutamic dehydrogenase.

DIURETIC

Artichoke administration stimulated urine excretion in animal studies.

LIPID-LOWERING

Artichoke leaf extract inhibited cholesterol biosynthesis in primary cultured rat hepatocytes and indirect modulation of hydroxymethylglutaryl-CoA-reductase activity is the most likely inhibitory mechanism. When several known constituents were screened for activity, cynaroside, and particularly its aglycone luteolin, were mainly responsible for the effect. These results have been confirmed recently.

Other Actions

Artichoke administration had beneficial effects on lowering blood glucose levels in alloxan-treated rabbits. One study using artichoke leaf juice showed it improved endothelial reactivity, most likely by its antioxidant constituents. According to German commission E, human studies have confirmed carminative, spasmolytic and anti-emetic actions.

Clinical note — Inulin: a natural prebiotic

Inulin is a plant-derived carbohydrate that is not digested or absorbed in the small intestine, but is fermented in the colon by beneficial bacteria. It functions as a prebiotic, stimulating growth of bifidobacteria in the intestine and has been associated with enhanced function of the gastrointestinal system and immune system. Increasing levels of beneficial bacteria, such as bifidobacteria, allows them to ‘out compete’ potentially detrimental organisms and improve the health of the host. Inulin also increases calcium and magnesium absorption, influences blood glucose levels and reduces the levels of cholesterol and serum lipids. Globe artichoke contains 3% of fresh-weight inulin and smaller amounts are found in the leaves.