Horny Goat Weed

Scientific Name(s): Epimedium grandiflorum L. Family: Berberidaceae (Barberry)

Common Name(s): Horny goat weed , Chien-Hsieh , Yin-Yang-Hua ( arrow-leaf barrenwort )

Uses

Historically, horny goat weed has been used in traditional Chinese medicine to “nourish” the kidney and as an aphrodisiac. However, clinical trial data are lacking to support these claims.

Dosing

There are no clinical studies of horny goat weed to provide a basis for dosage recommendations.

Contraindications

Contraindicated in patients with known hypersensitivity reactions to the Epimedium species.

Pregnancy/Lactation

Information regarding safety and efficacy in pregnancy and lactation is lacking. Avoid use.

Interactions

None well documented.

Adverse Reactions

High doses may cause a stimulatory effect and sweating. A case report of arrhythmia exists.

Toxicology

Information is limited.

Botany

Horny goat weed is a rhizomatous perennial herb. It is native to Japan, Korea, and parts of China and grows on hillsides, in cliff crevices, and in shady areas. The stems contain between 1 to 3 basal leaves. The plant has light yellow, violet, red, and white flowers, which appear in spring, along with oval fruits. 1 , 2

History

Historically, horny goat weed was thought to possess aphrodisiac effects and was used to treat impotence, spermatorrhea, and premature ejaculation. Herba Epimedii has been used traditionally in Korea, Japan, and China for more than 2,000 years to “nourish” the kidney. However, clinical trial data are lacking to support these claims. 2

Chemistry

A phytochemical review of the genus Epimedium has been published. 2 The medicinal properties of the plant are primarily contained within the leaves and roots, which contain flavonol glycosides and ikarisosides. The aerial parts of the plant contain more than 30 nonflavonoidal glycosides, including ionones, sesquiterepenes, and lignins. The glycosides of the dihydrophenanthrene and bibenzyl derivatives are found only in the genus Epimedium . In vitro studies have focused on the role of the constituent icariin in erectile dysfunction. 2 , 3 , 4 , 5 , 6 , 7

Uses and Pharmacology

Cardiovascular
Animal data

The results of a chemical study of the flavonoid icariin, isolated from the aerial parts of E. grandiflorum , referred to a hypotensive pharmacological effect. 8

Clinical data

Although clinical trials are lacking, Herba epimedii , a traditional Chinese medicine, was reported to exert a hypotensive effect in coronary heart disease. 2 Controlled clinical trials are lacking.

Erectile dysfunction
Animal data

Studies in rats have shown enhanced erectile tissue function and neurotrophic effects in vitro. 9 , 10 The effects have been attributed in part to the effect of the flavonol glycoside icariin in promoting release of nitric oxide in erectile tissue. 11 , 12 , 13 A combination preparation and its individual herbal components were tested for efficacy and safety in rats. Epimedium extract increased the penile erection index over control, but less than the combination preparation. 11 In vitro experiments have been conducted on extracts from a related plant, Epimedium brevicornum , while other studies suggest Epimedium species may exert estrogenic effects due to phytoestrogen constituents. 2

Clinical data

Controlled clinical trials are lacking.

Other uses
Antiviral

In vitro inhibitory action of E. grandiflorum has been demonstrated against the HIV virus. 14 E. grandiflorum has been used in combination with vitamin C in treating viral myocarditis. 15

Dosage

There are no clinical studies of horny goat weed to provide a basis for dosage recommendations. Tablets and capsules are sold in varying strengths (250 to 500 mg standardized to icariin content). 2

Pregnancy/Lactation

Information regarding safety and efficacy in pregnancy and lactation is lacking. Avoid use. Epimedium species may exert estrogenic effects due to phytoestrogen constituents. 2

Interactions

Information is lacking.

Adverse Reactions

Clinical trials are lacking to provide information regarding adverse reactions with the use of this product. High doses may cause a stimulatory effect and sweating. 2 A case report exists of tachyarrhythmia with consumption of horny goat weed, and the potential for products to be contaminated with other preparations has been noted. 16

Toxicology

Limited information exists. Studies on Herba Epimedii did not find mutagenicity or any important toxicity, although long-term administration has been associated with a decrease in thyroid activity in animal studies. 2

Bibliography

1. Lovejoy A. Epimediums . Horticulture . 1994;72:42-47.
2. Ma H, He X, Yang Y, Li M, Hao D, Jia ZJ. The genus Epimedium : an ethnopharmacological and phytochemical review. J Ethnopharmacol . 2011;134(3):519-541.
3. Fukai T, Nomura T. Seven prenylated flavonol glycosides from two Epimedium species. Phytochemistry . 1988;27(1):259-266.
4. Miyase T, Ueno A. Ionone and bibenzyl glycosides from Epimedium grandiflorum var. Thunbergianum . Phytochemistry . 1991;30(5):1727-1728.
5. Tokuoka Y, Daigo K, Takemoto T. Studies on the constituents of Epimedium . ΙΙΙ. Lignoids of Epimedium grandiflorum Morr. (author's transl) [in Japanese]. Yakugaku Zasshi . 1975;95(5):557-563.
6. Tokuoka Y, Daigo K, Takemoto T. Studies on the constituents of Epimedium . V. Flavonoids of Epimedium grandiflorum Morr. (4) (author's transl) [in Japanese]. Yakugaku Zasshi . 1975;95(7):825-829.
7. Yoshitama K. Anthocyanins and their distribution in the genus Epimedium . Bot Mag . 1984;97:429-435.
8. Zhu SC. Clinical observations on 36 cases of viral myocarditis treated with Epimedium grandiflorum Moor and vitamin C [in Chinese]. Zhong Xi Yi Jie He Za Zhi . 1984;4(9):523-524, 514.
9. Albersen M, Shindel AW, Mwamukonda KB, Lue TF. The future is today: emerging drugs for the treatment of erectile dysfunction. Expert Opin Emerg Drugs . 2010;15(3):467-480.
10. Shindel AW, Xin ZC, Lin G, et al. Erectogenic and neurotrophic effects of icariin, a purified extract of horny goat weed ( Epimedium spp.) in vitro and in vivo. J Sex Med . 2010;7(4 pt 1):1518-1528.
11. Qinna N, Taha H, Matalka KZ, Badwan AA. A new herbal combination, Etana , for enhancing erectile function: an efficacy and safety study in animals. Int J Impot Res . 2009;21(5):315-320.
12. Liu WJ, Xin ZC, Xin H, Yuan YM, Tian L, Guo YL. Effects of icariin on erectile function and expression of nitric oxide synthase isoforms in castrated rats. Asian J Androl . 2005;7(4):381-388.
13. Cirigliano MD, Szapary P. Horny goat weed for erectile dysfunction. Altern Med Alert . 2001;4:19-22.
14. In vitro screening of traditional medicines for anti-HIV activity: memorandum from a WHO meeting. Bull World Health Organ . 1989;67(6):613-618.
15. Kon L, Li Y, He A, Min A. Studies on HMQC and HMBC spectra of a hypotensive compound icariin. Chin J Magn Reson . 1996;13:595-600.
16. Partin JF, Pushkin YR. Tachyarrhythmia and hypomania with horny goat weed. Psychosomatics . 2004;45(6):536-537.

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