Cynarine is a polyphenol that was first isolated and identified from the artichoke (Cynara scolymus) in 1954.1
The artichoke plant is able to synthesize cynarine from a quinic acid and two units of caffeic acid (see figure below).
The artichoke is an important part of the Mediterranean diet and has been studied for a variety of health promoting properties. A search of PubMed will find there are about 1,000 research articles on artichoke. 
One area of interest for artichoke has been its possible cholesterol lowering activity. For example, pre-clinical studies using cells and animal models have found that artichoke and a compound in artichoke, cynarine, can lower cholesterol.2
The possible mechanisms for lowering cholesterol that have been suggested include:
- Inhibiting cholesterol synthesis
- Inhibiting LDL oxidation by scavenging for free radicals.
These mechanisms were identified using cell based techniques, however, it is unclear if these same mechanisms will be observed in a living organism (i.e. animals or humans).
Another consideration is that cynarine is often studied as an artichoke extract. This means that there are many different phytochemicals present in the extract that could have cholesterol lowering properties.
For example, luteolin is a flavonoid, that could also be responsible for lowering cholesterol levels.3
The prescription drugs known as “Statins” lower cholesterol by directly inhibiting HMG-CoA reductase, the enzyme responsible for making cholesterol. Examples of statins including simvastatin (Zocor®), lovastatin (Mevacor), fluvastatin (Pravastatin®), and rosuvastatin (Crestor®).
Studies have found that the luteolin does not inhibit the HMG-CoA reductase enzyme the way same way statins do suggesting a slightly different mechanism.4
The mechanism appears to be different in that the overall activity of the enzyme is decreased. This action appears to be an “indirect inhibition” as opposed to a “direct inhibition”.
Here is a clinical trial that recently studied artichoke extract for lowering cholesterol with very interesting results.
With regard to cynarine the mechanism is not described, however, there is some structural similarity between the luetolin and cynarine.
Take away message
Compounds present in the artichoke leaf including cynarine may contribute to the cholesterol lowering activity observed in clinical trials. The mechanism is not fully understood, however, the evidence suggests that it may work through a mechanism different than the prescription statin drugs on the market. More research is needed to understand cynarine can inhibit cholesterol synthesis by an ‘indirect’ inhibition of key enzymes in cholesterol synthesis.
References
1. Luigi Panizzi & Maria Luisa Scarpati. Constitution of Cynarine, the Active Principle of the Artichoke. Nature volume 174, page 1062 (04 December 1954)
2. Ben Salem M, et al. Pharmacological Studies of Artichoke Leaf Extract and Their Health Benefits. Plants Foods for Human Nutrition. 2015 December; Volume 70 (Issue 4): Pages 441-53.
3. Wong T,y et al. Apigenin and luteolin display differential hypocholesterolemic mechanisms in mice fed a high-fat diet. Biomedicine and Pharmacotherapy. Volume 96, December 2017, Pages 1000-1007
4. Sa C, et al. Effects on Liver Lipid Metabolism of the Naturally Occurring Dietary Flavone Luteolin-7-glucoside. Evidence-Based Complementary and Alternative Medicine. Volume 2015 (2015), Article ID 647832
His research on plant medicine has led to more than 45 publications and abstracts.This research has been presented at international meetings in the USA, France, Turkey, Peru, Israel, Austria, and Italy.
Categories: Antioxidant, Cholesterol, Inflammation, Liver