HerbalEGram: Volume 17, Issue 6, June 2020

By Jenny Perez^a and Amanda Reat^b

^aABC Education Coordinator

^bABC Dietetic Intern (Texas State, 2013)

Editor’s note: Every other month, HerbalEGram highlights a conventional food and briefly explores its history, traditional uses, nutritional profile, and modern medicinal research. We also feature a nutritious recipe for an easy-to-prepare dish with each article to encourage readers to experience the extensive benefits of these whole foods. With this series, we hope our readers will gain a new appreciation for the foods they see at the supermarket and frequently include in their diets. We would like to acknowledge ABC Chief Science Officer Stefan Gafner, PhD, and HerbalGram Associate Editor Hannah Bauman for their contributions to this project.

Overview

Plants belonging to the genus Cynara are known as thistles and typically are large and spiny. These members of the daisy family (Asteraceae) are native to the Mediterranean region, northwest Africa, and the Canary Islands.^1-4 The cultivated artichoke (Cynara cardunculus ssp. scolymus) and the cultivated leafy cardoon (C. cardunculus var. altilis) both descended from the wild cardoon (C. cardunculus).^5,6 The subspecies name comes from the word scolymos, which means “spiny” in ancient Greek, and refers to thistles in general and specifically to the spines found on the bracts that enclose the flower heads of the edible portion of artichoke.^6,7 The wild cardoon evolved into these common food crops through human cultivation and selection pressure for desirable traits such as large, non-spiny heads (artichoke) or non-spiny, large-stalked tender leaves (cardoon).

In dry, subtropical climates, the artichoke plant is cultivated as an herbaceous perennial while the cardoon is grown as an annual.^1,6 Both have deeply toothed, greyish-green leaves with pointed lobes that grow up to three feet long. The sturdy flower stalks arise from a basal rosette and can grow eight feet tall, producing three to five fleshy flower heads that are enclosed in thick, green, edible bracts.^2,5 The most commonly consumed part of artichokes are the large immature flowers that are harvested when very young or before the numerous triangular-shaped bracts curl away, which indicates that the flower head will soon open and no longer be edible.^3,7,8 At the base of each flower head is an edible fleshy receptacle known as the artichoke heart. The immature florets, called the choke, are inedible and removed before processing the artichoke heart for culinary applications.^8,9 If flowers are allowed to open and mature, they produce a thistle-like violet-blue bloom and can reach up to seven inches across.⁵ The cardoon is cultivated for its fleshy stems and leaf stalks.

Historical and Commercial Uses

The history of the Cynara genus dates back to ancient Greece. The first written record of Cynara appeared in the writings of Theophrastus in the fourth century BCE.⁴ In the first century CE, Pliny the Elder recommended artichoke and cardoon for intestinal distress and freshening the breath; he also recommended it for more unusual applications, including curing baldness and the conception of boys.¹⁰ Both Greeks and Romans used the artichoke leaf as a choleretic (bile-increasing) agent and a diuretic.¹

While cardoon originally was domesticated within Spain or France, artichokes were first cultivated in the Naples region of Italy in the mid-15th century and gradually continued throughout other parts of Europe.^5,6,8 Italian noblewoman Catherine de Medici introduced artichokes to France when she became queen in 1547. The artichoke also gained a reputation as an aphrodisiac and eventually became known throughout Europe. It even appeared on the tables of monarchs, including Henry VIII of England. French colonists brought the artichoke to North America in the 1800s and by the early 20th century, artichokes were extensively cultivated in California.⁵

Today, artichokes are still enjoyed as an important vegetable, especially in France, Italy, Spain, and Belgium, where it is commonly cultivated.⁸ In the United States, 100% of all commercially grown artichokes are cultivated in California.¹¹ Numerous cultivars have been developed to improve flavor and hardiness.³

When artichokes are served whole, the leaf bracts are pulled off one by one and scraped against the teeth to eat the pulp at its base. After the leaves are removed, the choke is peeled away to reveal the sweet and tender artichoke heart.¹² Artichokes, whole or the hearts, are commonly preserved in brine or spiced oil and are also stuffed, eaten with butter or cream sauce, or in salads or casseroles.⁸ Cardoon leaves are enjoyed as a regional cuisine in Mediterranean countries where they are baked, boiled, fried, or braised.¹³ Mature artichoke and cardoon flowers contain proteolytic enzymes that act as natural coagulants and are used as a vegetarian alternative to rennet in cheese-making.^14,15

Many of the traditional uses of artichoke and cardoon focus on liver health as a hepatoprotective agent.¹ However, the plant has also been traditionally used to stimulate appetite and enhance digestion by increasing bile flow from the liver, which has natural laxative effects.^1,7,16,17 In Germany, Sweden, and Finland, herbal preparations made from artichoke leaves are still used for these purposes and as an appetite stimulant in pediatric populations.^1,18 Cynar, an Italian liqueur made from artichoke, is bittersweet and consumed either before (aperitif) or after (digestif) meals to enhance digestion.¹⁴

Nutrients and Phytochemicals

A traditional component of Mediterranean diets, artichokes are a low-calorie vegetable, providing only 60 calories per 100-gram serving.^4,8 The edible portion of an artichoke contains cholesterol-lowering dietary fiber and has no fat or cholesterol.^11,19 Artichoke hearts are an excellent dietary source of vitamin C and folate and a good source of minerals, including magnesium, potassium, and phosphorus.^4,8 Artichoke hearts are high in fiber and can counteract constipation.²⁰ Beyond its basic nutritional value, artichoke hearts are considered a functional food with natural components that reduce the risk of specific diseases.^14,21 An indigestible carbohydrate known as inulin is most concentrated in the external bracts and flower heads of the artichoke.⁷ Inulin has been used to replace fat in table spreads, baked goods, fillings, dairy products, frozen desserts and salad dressings.¹⁵ Inulin acts as a natural prebiotic that “feeds” the beneficial bacteria, specifically Bifidobacterium, in the large intestine of humans and animals, increasing the efficiency and frequency of bowel movements.^6,14 Enhanced gut microflora is associated with improvements in mineral absorption, blood lipid composition, and the prevention of colon cancer.⁷

The heads and leaves of artichoke and cardoon have high levels of important phytochemicals. Phenols, flavonoids, and anthocyanins are all potent antioxidants which protect the cells of the body from damage and inhibit low-density lipoprotein (LDL) cholesterol oxidation. The total antioxidant capacity of artichoke flower heads is one of the highest reported for vegetables, and artichokes are ranked seventh on the USDA’s Top 20 Foods High in Antioxidants.²³ This is attributed to the high levels of bioactive polyphenols such as caffeoyquinic acids (e.g., cynarin and chlorogenic acid) and flavonoids in the artichoke’s inner bracts and receptacles.²¹ While cooking artichoke can decrease its overall flavonoid concentration, steaming has been found to increase its antioxidant capacity considerably.^15,24 In addition to cynarin and chlorogenic acid, research indicates that artichoke and cardoon contain other phytochemicals that reduce cholesterol and inflammation and have potential cancer-preventing properties. These phytochemicals and their associated properties are listed in Table 1.

Table 1: Polyphenols in Artichokes and Cardoons

Modern Research and Potential Health Benefits

Current research supports the long-standing medicinal uses of artichoke and cardoon leaf extracts as a cardioprotective, hepatoprotective, and intestinal soothing agent, as well as its cancer chemopreventive properties. The main biological activities attributed to both artichokes and cardoons are hepatoprotection, prevention of colon cancer, stimulation of bile secretion, and lowering of cholesterol.^14,16,25 A limitation of current research is the lack of studies that have specifically investigated the effects of artichoke heart consumption.¹⁹ Further studies are necessary to further investigate artichoke metabolites and their mechanisms of action.¹⁴

Cardioprotective Effects

High cholesterol is a risk factor for cardiovascular disease. There is an increasing interest in natural lipid-lowering compounds that may delay or circumvent conventional antihypercholesterolemic drug therapy.²⁶ Artichoke and cardoon are a fundamental part of the Mediterranean diet, which offers an array of nutrients and phytochemicals that promote overall health.

While artichoke hearts provide sufficient cholesterol-lowering fiber, recent clinical trials have shown that artichoke leaf extract (ALE) has greater potential to reduce total cholesterol and LDL cholesterol levels and, in some cases, reduce trigylceride levels and increase high-density lipoprotein (HDL) cholesterol levels.^18,27-31 Artichoke and cardoon’s ability to lower cholesterol is in part attributed to improving bile salt excretion via bowel movements.³² Additionally, the inulin in the plant has been shown to increase production of beneficial bacteria (i.e., Bifidobacteria) which, in turn, produces positive effects on blood lipid composition.⁴

A 2013 Cochrane Review of three randomized, controlled trials for ALE found a modest positive effect on total and LDL cholesterol levels, with the suggestion that patients with severely elevated cholesterol levels may benefit more from ALE treatment than those with moderately high levels.³¹ Reported adverse events were mild, transient, and infrequent. While the available clinical trial literature was insufficient for the authors to recommend ALE as a treatment for high cholesterol, they concluded that the lipid-lowering effects shown in in vitro and animal studies, along with the clinical trials reviewed, were promising enough that larger and better-controlled clinical trials were needed to establish whether ALE was a safe and effective treatment for patients with high cholesterol on a long-term basis as a lipid-lowering therapy.

A 2017 meta-analysis by Sahebkar et al. reviewed nine randomized, controlled clinical trials investigating the LDL-lowering effects of ALE. ALE supplementation, ranging from 500-2,700 mg per day, was associated with significantly reduced total cholesterol and LDL cholesterol levels in patients with moderate-to-severe hypercholesterolemia with an average baseline LDL level of 213 mg/dL.²⁶ The cholesterol-lowering effect appeared to be unrelated to dose and duration of treatment, but ALE’s efficacy was directed related to baseline LDL cholesterol levels.²⁶ These findings are similar to those of the 2013 Cochrane Review. Overall, the data support the potential clinical use of ALE supplementation to achieve a mild but significant reduction in LDL cholesterol. ALE treatment did not have any effect on reducing triglyceride levels or increasing HDL cholesterol levels. Further clinical trials are needed to determine if ALE, alone or in combination with lipid-lowering drugs such as statins, can reduce risk of atherosclerosis and improve long-term clinical outcomes in the treatment of high LDL cholesterol.¹⁹

Gastrointestinal Effects

Although less research has focused on the gastrointestinal benefits of artichoke, studies show that ALE is associated with improvements in dyspepsia (abdominal discomfort) symptoms.^33,34 More specifically, supplementation with ALE has been shown to significantly reduce abdominal pain and discomfort, cramps, acid reflux, the feelings of fullness, pressure, bloating, nausea, and vomiting.^18.34,35 Due to the significant overlap between symptoms of dyspepsia and irritable bowel syndrome (IBS), one-third of individuals with functional dyspepsia also suffer from IBS.¹⁸ Several studies have indicated that artichoke leaf extract can be an effective treatment for IBS symptoms.^18,36 Furthermore, ALE is also thought to be an antispasmodic agent, a property that may contribute to the relief of intestinal cramps, nausea, and vomiting.³⁵ Research suggests that the moderate amounts of cynaropicrin present in ALE greatly contribute to its widespread use for relieving dyspeptic symptoms.

Hepatoprotective Effects

Nonalcoholic fatty liver disease (NAFLD) is the most common cause of chronic liver disease globally, and other than dietary modification and regular exercise, there are limited therapeutic treatments available. This disease occurs when the liver’s ability to metabolize fats is impaired, making it more susceptible to injury and inflammation.³² NAFLD is associated with metabolic syndrome; therefore, obesity, insulin resistance, impaired glucose tolerance, and high cholesterol often are disease cofactors. Weight loss alone may not be enough to reverse the progression of liver damage.

Cynarin is associated with artichoke and cardoon’s choleretic and hepatoprotective properties.¹⁴ ALE supplementation reduces high cholesterol, especially LDL cholesterol. In a pilot clinical trial that tested the ability of ALE to improve NAFLD, patients receiving ALE for a two-month period showed significant improvements in NAFLD severity (reduced liver size and portal vein diameter and increased blood flow to the liver) as determined by liver sonography, compared to placebo.³² Total bilirubin, aspartate aminotransferase (AST), alanine aminotransferase (ALT), and uric acid levels were significantly reduced. In addition, the AST/ALT ratio and the AST/platelet ratio (APRI) improved, indicating improved liver function in the patients supplementing with ALE. Finally, patients supplementing with ALE experienced an indirect improvement of NAFLD indices via a decrease in body mass index (BMI), which is crucial to improving NAFLD patient outcomes.

According to the World Health Organization, approximately 700,000 people die annually from hepatitis C-related liver diseases.³⁵ Managing oxidative stress and subsequent liver damage is crucial to slowing the progression of hepatitis-C viral (HCV) infections. Cynaropicrin, a water-soluble compound isolated from artichoke, is a powerful antioxidant and anti-inflammatory compound. In vitro and in vivo studies have demonstrated the protective and regenerative effects that cynarin and cynaropicrin, present in ALE, have on liver health. Cynaropicrin, specifically, appears to be an anti-HCV entry inhibitor and may play a key role in helping patients with end-stage liver diseases undergoing liver transplantation, where reinfection of the graft is common and can accelerate progression of liver diseases. Clinical trials on ALE have demonstrated that it is safe and well tolerated, with little to no adverse effects reported. However, these finding need to be confirmed with larger, randomized clinical trials to further investigate ALE’s clinical efficacy.^16,32

Consumer Considerations

During the last 20 years, artichoke consumption has increased by 40%.¹⁵ Currently, Italy is the leading producer of artichokes, followed by Spain, France, and Greece.^4,14 Cardoon has much more limited cultivation, though it has traditional importance as both food and medicine in northern Mediterranean areas. Commercially, globe artichokes are available fresh, canned, or frozen. More than 1,678,872 tons of artichokes are produced annually, of which more than 60% is produced in Europe.^14, North African countries, including Egypt, Morocco, and Algeria, also contribute to worldwide artichoke production. China is the only Asian country that is among the top 10 global artichoke producers.³⁶ The United States is the ninth largest producer of artichokes, with most of the crop originating in the state of California.

Artichoke and cardoon thrive in dry Mediterranean conditions where most rainfall occurs during the winter season.¹³ Their deep root systems helps them withstand periods of low rainfall. The bitter compounds present in the leaves, such as cynaropicrin, make them less appealing to common garden pests.^4,21,35

Given that artichokes are grown for only their immature flower heads, a significant amount of biomass (80-85%) from the inedible parts of the artichoke, including the leaves, external bracts, and stems, still contains high levels of polyphenols and inulin, and these byproducts are being investigated for use as a food additive, plant dye, biofuel, and in paper-pulp production.^4,14 Plants and stems are traditionally used as nutritious forage for hens, goats, and other farm animals.^14,15

Nutrient Profile³⁸
Per 1 medium artichoke (approx. 128 g)

Macronutrients

60 calories
4.2 g protein
13.5 g carbohydrate
0.2 g fat

Micronutrients

Excellent source of:

Dietary Fiber: 6.9 g (27.6% DV)
Vitamin C: 15 mg (25% DV)
Vitamin K: 18.9 mcg (24% DV)
Folate: 87 mcg (21.8% DV)

Very good source of:

Magnesium: 77 mg (19.3% DV)
Potassium: 474 mg (13.5% DV)
Phosphorus: 115 mg (11.5% DV)

Good source of:

Iron: 1.64 mg (9% DV)
Niacin: 1.34 mg (6.7% DV)
Calcium: 56 mg (5.6% DV)

DV = Daily Value as established by the US Food and Drug Administration, based on a 2,000-calorie diet.

Image credits:

All images ©2020 Steven Foster

References

1. Blumenthal M, Goldberg A, Brinckmann J, eds. Herbal Medicine: Expanded Commission E Monographs. Austin, TX: American Botanical Council; Newton, MA: Integrative Medicine Communications; 2000.
2. Artichoke. Encyclopedia Britannica Online. Available at: www.britannica.com/plant/artichoke. Accessed April 21, 2020.
3. Artichoke. New World Encyclopedia Online. Available at: www.newworldencyclopedia.org/entry/artichoke. Accessed May 27, 2020.
4. Christaki E, Bonos E, Florou-Paneri P. Nutritional and functional properties of Cynara crops (globe artichoke and cardoon) and their potential applications: A review. International Journal of Applied Science and Technology. 2012;2(2):64-70.
5. National Geographic Society. Edible: An Illustrated Guide to the World’s Food Plants. Lane Cove, Australia: Global Book Publishing; 2008.
6. Sonnate G, Pignone D, Hammer K. The domestication of artichoke and cardoon: From Roman times to the genomic age. Annals of Botany. 2007;100:1095-1100.
7. Lattanzio V, Kroon PA, Linsalata V, Cardinali A. Globe artichoke: A functional food and source of nutraceutical ingredients. Journal of Functional Foods. 2009;1:131-144.
8. Van Wyk B-E. Food Plants of the World. Portland, OR: Timber Press; 2006.
9. Artichoke. Louis Bonduelle Foundation. Available at: www.fondation-louisbonduelle.org/en/vegetable/artichoke/. Accessed May 26, 2020.
10. Rupp R. The history of artichokes. National Geographic website. November 12, 2014. www.nationalgeographic.com/culture/food/the-plate/2014/11/12/artichokes/. Accessed March 23, 2015.
11. Artichoke. California Artichoke Advisory Board website. Available at: http://artichokes.org/. Accessed May 27, 2020.
12. Artichoke hearts. University of Wyoming College of Agriculture and Natural Resources Extension website. Available at: https://uwyoextension.org/uwnutrition/2015/04/09/artichoke-hearts/. Accessed May 27, 2020.
13. Traditional crops: Cardoon. Food and Agriculture Organization of the United Nations website. Available at: www.fao.org/traditional-crops/cardoon/en/. Accessed May 4, 2020.
14. de Falco B, Incerti G, Amato M, et al. Artichoke: botanical, agronomical, phytochemical, and pharmacological overview. Phytochemistry Reviews. 2015;14:993-1018.
15. Gostin AI and Waisundara VY. Edible flowers as functional food: A review on artichoke (Cynara cardunculus). Trends in Food Science and Technology. 2019;(86):381-391.
16. Aksu O and Altinerim B. Hepatoprotective effects of artichoke (Cynara scolymus). Bilim ve Genclik Dergisi. 2013;1(2):44-49.
17. Choleretic. The Naturopathic Herbalist website. Available at: https://thenaturopathicherbalist.com/herbal-actions/b-d/choleretic/ Accessed May 26, 2020.
18. Walker AF, Middleton RW, Petrowicz O. Artichoke leaf extract reduces symptoms of irritable bowel syndrome in a post-marketing surveillance study. Phytotherapy Research, 2001;15:58-61.
19. Santos H, Bueno A, Mota J. The effect of artichoke on lipid profile: A review of possible mechanisms of action. Pharmacological Research. 2018;137:170-178.
20. Mentel I, Cieslik E, Walkowska I, et al. Content of nutritive components, dietary fiber, and energy value of artichoke depending on the variety. Acta Scientiarum Polonorum Technologia Alimentaria. 2012;11(2):201-207.
21. Ceccarelli N, Curadi M, Picciarelli, et al. Globe artichoke as a functional food. Mediterranean Journal of Nutrition and Metabolism. June 2010;3:197-201.
22. Salehi B, Venditti, Sharif-Rad M, et al. The therapeutic potential of apigenin. International Journal of Molecular Sciences. 2019;(2);1305-1331.
23. Reilly CT. Top 20 Foods High in Antioxidants. St. John’s Health website. Available at: www.stjohns.health/documents/cognitive-health/top-20-foods-high-in-antioxidants.pdf. Accessed May 27, 2020.
24. Ferracane R, Pellegrini N, Visconti A, et al. Effects of different cooking methods on antioxidant profile, antioxidant capacity, and physical characteristics of artichoke. Journal of Agricultural and Food Chemistry. 2008;56(18):8601-8608.
25. Bekheet S, Sota V. Biodiversity and medicinal uses of globe artichoke (Cynara scolymus) plant. Journal of Biodiversity Conservation and Bioresource Management. 2019;5(1)39-54.
26. Sahebkar A, Pirro M, Banach M, et al. Lipid-lowering activity of artichoke extracts: A systematic review and meta-analysis. Critical Reviews in Food Science and Nutrition. 2017;58(15):2549-2556
27. Sannia A. Phytotherapy with a mixture of dry extracts with hepato-protective effects containing artichoke leaves in the management of functional dyspepsia symptoms. Minerva Gastroenterology Dietology. 2010;56(2):93-94.
28. Rondanelli M, Giacosa A, Opizzi A, et al. Beneficial effects of artichoke leaf extract supplementation on increasing HDL-cholesterol in subjects with primary mild hypercholesterolaemia: a double-blind, randomized, placebo-controlled trial. International Journal of Food Science Nutrition. 2013;64(1):7-15.
29. Bundy R, Walker AF, Middleton RW, et al. Artichoke leaf extract (Cynara scolymus) reduces plasma cholesterol in otherwise healthy hypercholesterolemic adults: A randomized, double blind, placebo controlled trial. Phytomedicine. 2008;15:668-675.
30. Lupattelli G, Marchesi S, Lombardini R, et al. Artichoke juice improves endothelial function in hyperlipemia. Life Sciences. 2004;76(7):775-782.
31. Wider B, Pittler MH, Thompson‐Coon J, Ernst E. Artichoke leaf extract for treating hypercholesterolaemia. Cochrane Database of Systematic Reviews. 2013;3.
32. Panahi Y, Kianpour P, Mohtashami R, et al. Efficacy of artichoke leaf extract in non-alcoholic fatty liver disease: a pilot double-blind randomized controlled trial. Phytotherapy Research. 2018;32:1382-1387.
33. Holtmann G, Adam B, Haag S, et al. Efficacy of artichoke leaf extract in the treatment of patients with functional dyspepsia: a six week placebo-controlled, double blind, multicentre trial. Alimentary Pharmacology Therapy. 2003;18:1099-1105.
34. Marakis G, Walker AF, Middleton RW, et al. Artichoke leaf extract reduces mild dyspepsia in an open study. Phytomedicine. 2002;9:694-699.
35. Elsebai M, Mocan A, Atanasov A. Cynaropicrin: a comprehensive research review and therapeutic potential as an anti-hepatitis C virus agent. Frontiers in Pharmacology. 2016;7(472):1-15.
36. Bekheet S. and Sota V. Biodiversity and medicinal uses of globe artichoke (Cynara scolymus) plant. Journal of Biodiversity, Conservation and Bioresource Management. 2019; 5(1):39-54.
37. Bundy R, Walker AF, Middleton RW, et al. Artichoke leaf extract reduces symptoms of irritable bowel syndrome and improves quality of life in otherwise healthy volunteers suffering from concomitant dyspepsia: a subset analysis. Journal of Alternative and Complementary Medicine. 2004 Aug;10(4):667-669.
38. Artichokes, (globe or french), raw. FoodData Central website. United States Department of Agriculture. Available at: https://fdc.nal.usda.gov/fdc-app.html#/food-details/169205/nutrients. Accessed May 19, 2020.
39. Karadsheh S. Mediterranean roasted artichokes. The Mediterranean Dish. Available at: www.themediterraneandish.com/mediterranean-roasted-artichoke-recipe/. Accessed May 5, 2020.
40. Bauman H, Applegate C. Food as Medicine: Shallot (Allium cepa var. aggregatum, Amaryllidaceae). HerbalEGram. 2017;14(2). Available at: http://cms.herbalgram.org/heg/volume14/02February/FAMShallot.html. Accessed June 4, 2020.
41. Bauman H, Silva M. Food as Medicine: Caper (Capparis spinosa, Capparaceae). HerbalEGram. 2017;14(5). Available at: http://cms.herbalgram.org/heg/volume14/05May/FoodasMedicineCaper.html. Accessed May 19, 2020.