Blessed Thistle

JUN 2008

Cnicus benedictus Family: L. Asteraceae (daisies)

Holy thistle , St. Benedict's thistle , cardin , spotted thistle , carduus benedictus

Uses

Blessed thistle is used to stimulate secretion of gastric juices and saliva, to increase appetite and facilitate digestion, and to stimulate the flow of bile. It has been used as a minor component of the alternative cancer remedy FlorEssence and has antibacterial and antifungal activity. Other pharmacologic activities for blessed thistle include blockade of gonadotropin and antiinflammatory properties. However, there are no reported human clinical trials for any of these uses.

Dosing

There are no clinical studies to justify dosing of blessed thistle. Traditionally, 4 to 6 g of blessed thistle is used daily.

Contraindications

Because of its irritating effect, blessed thistle is contraindicated in gastric ulcer or in inflammatory bowel conditions such as Crohn disease.

Pregnancy/Lactation

Blessed thistle should not be used in pregnancy. No evidence exists to support the efficacy of its common use to promote lactation.

Interactions

None well documented.

Adverse Reactions

People sensitive to the sesquiterpene lactones of other asteraceous plants should use blessed thistle with caution. Blessed thistle extract was strongly sensitizing in a study of 12 species in the family Asteraceae.

Toxicology

At high single doses (5 to 6 g) blessed thistle is known to be emetic.

Blessed thistle is native to North Africa, southern Europe, and western Asia. It grows most often in stony, uncultivated places. It is an annual, growing about 0.7 m in height, with pale yellow, prickly flowers. The whole plant is covered with down.

The plant was widely cultivated in the Middle Ages in Europe. Its medicinal use was mentioned by Shakespeare in his play Much Ado About Nothing and was prominent in many of the herbals of the period. ^1, It was thought to be useful in treating plague; however, its main uses were for digestive complaints, gout, fever, and headache. ² Blessed thistle also was recommended as an emmenagogue, galactogogue, and abortifacient. The dried leaves, stems, and flowers are used medicinally. It is used in flavoring Benedictine liqueur and has GRAS (generally recognized as safe) status for alcoholic beverage use only. Blessed thistle has been used as a secondary component of the polyherbal alternative cancer treatment FlorEssence (Flora Manufacturing and Distributing, Inc.). It is available as a single herb and in homeopathic preparations. Blessed thistle was approved by the German Commission E for treatment of dyspepsia and loss of appetite.

The most prominent constituent of blessed thistle is the bitter sesquiterpene lactone ester cnicin. ^3, Other germacrane sesquiterpenes include salonitenolide and artemisiifolin. ^4, The bitter lignans arctiin, arctigenin, and nortracheloside are also present. ^5, Two C13 polyacetylenes have been isolated as well. ^6, A patent discloses antifungal proteins active against plant pathogenic fungi, isolated from the seed of blessed thistle. ⁷

Bitter principles such as cnicin stimulate secretion of gastric juices and saliva, thereby increasing appetite and facilitating digestion. They are also capable of stimulating the flow of bile.

Blessed thistle is a minor component of the alternative cancer remedy FlorEssence , one of 8 herbs in the formulation. ^8, In this context, cnicin is cytotoxic to leukemia cells, while sesquitepenes, lacking the ester moiety, had lesser activity. ^9, , ^10, The same structural requirements apply to antibacterial activity. ^11, Similarly, cnicin was the most active sesquiterpene against a variety of fungi in another study. ¹²

Other pharmacologic activity found for blessed thistle include blockade of gonadotropin. ^13, Cnicin has been shown to have antiinflammatory properties in a rat paw edema test. ¹⁴

There are no reported human clinical trials for any of these indications.

There are no clinical studies to justify dosing of blessed thistle. Traditionally, 4 to 6 g of blessed thistle is used daily.

Blessed thistle should not be used in pregnancy. No evidence exists to support the efficacy of its common use to promote lactation.

None well documented.

People sensitive to the sesquiterpene lactones of other asteraceous plants should use blessed thistle with caution. Blessed thistle extract was found to be strongly sensitizing in a study of 12 species in the family Asteraceae.

Cnicin is strongly irritating upon intraperitoneal injection. ^14, Because of this irritating effect, blessed thistle is contraindicated in gastric ulcer or in inflammatory bowel conditions such as Crohn disease. At high doses (5 to 6 g), blessed thistle is known to be emetic. The oral median lethal dose for cnicin in mice was 1.6 to 3.2 mmol/kg. ¹⁴

1. Shakespeare W . Much Ado about Nothing . 3.4. London: Oxford University Press; 1914.

2. Grieve MA . Modern Herbal . London: Jonathan Cape, Ltd.; 1931.

3. VanhaelenFastré R . Cnicus benedictus . Separation of antimicrobial constituents . Plantes Medicinales et Phytotherapie . 1968;2:294.

4. VanhaelenFastré R , Vanhaelen M . Presence of salonitenolide in Cnicus benedictus [in French]. Planta Med . 1974;26:375379. PubMed

5. Vanhaelen M , VanhaelenFastré R . Lactonic lignans from Cnicus benedictus . Phytochemistry . 1975;14:2709.

6. VanhaelenFastré R . Polyacetylene compounds from Cnicus benedictus . Planta Med . 1974;25:4759. PubMed

7. Broekaert WF, et al . A family of fungicidal and bactericidal proteins from plant seeds. WO Patent No. 9305153.

8. Tamayo C , Richardson MA , Diamond S , Skoda I . The chemistry and biological activity of herbs used in FlorEssence herbal tonic and Essiac . Phytother Res . 2000;14:114.

9. VanhaelenFastré R . Antibiotic and cytotoxic activity of cnicin isolated from Cnicus benedictus [in French]. Pharm Belg . 1972;27:683688. PubMed

10. VanhaelenFastré R , Vanhaelen M . Antibiotic and cytotoxic activity of cnicin and of its hydrolysis products. Chemical structure  biological activity relationship . Planta Med . 1976;29:179189. PubMed

11. Bruno M , Rosselli S , Maggio A , Raccuglia RA , Napolitano F , Senatore F . Antibacterial evaluation of cnicin and some natural and semisynthetic analogues . Planta Med . 2003;69:277281.

12. Panagouleas C , Skaltsa H , Lazari D , Skaltsounis AL , Sokovic M . Antifungal activity of secondary metabolites of Centaurea raphanina ssp. mixta, growing wild in Greece . Pharm Bio . 2003;41:266.

13. Graham RC , Noble Rl . Comparison of in vitro activity of various species of Lithospermum and other plants to inactivate gonadotropin . Endocrinology . 1955;56:239247. PubMed

14. Schneider G , Lachner I . Analysis and action of cnicin [in German]. Planta Med . 1987;53:247251.