Skullcap
American skullcap; Mad-dog skullcap; Scullcap; Scutellaria lateriflora; Chinese skullcap; Huang Qin; Wogon; Scutellaria baicalensis
Skullcap can refer to 2 herbs: American skullcap (Scutellaria lateriflora) and Chinese skullcap (Scutellaria baicalensis). Both forms of skullcap are used to treat different conditions and are not interchangeable.
American skullcap is native to North America, but it is now widely cultivated in Europe and other areas of the world. It has been used for more than 200 years as a mild relaxant and as a therapy for anxiety, nervous tension, and convulsions. Studies show American skullcap has significant antioxidant effects, and may help protect against neurological disorders, such as Alzheimer's disease, Parkinson's disease, anxiety, and depression. There's even some evidence to suggest that American skullcap may inhibit food allergic response. Today, other herbs (such as valerian) are more commonly used, although American skullcap may be combined with other calming herbs in some preparations.
Most of the studies done on skullcap have examined Chinese skullcap. Native to China and parts of Russia, Chinese skullcap has been used in traditional Chinese medicine to treat allergies, infections, inflammation, cancer, and headaches. It may also have antifungal and antiviral effects. Animal studies suggest that Chinese skullcap may help reduce symptoms of diabetes and hypertension (high blood pressure), but scientists don't know if Chinese scullcap has the same effect in humans. In test tubes and animal studies, Chinese skullcap appears to have some cancer-fighting properties. More research is needed to determine any benefit.
Plant Description
American skullcap derives its name from the caplike appearance of the outer whorl of its small blue or purple flowers. It is a slender, heavily-branched plant that grows to a height of 2 to 4 feet and blooms each July. It grows wild in woods and meadows.
Chinese skullcap is related to and resembles American skullcap, but it is a different plant. Its single stems bear a profusion of blue or purple flowers.
Parts Used
American skullcapThe leaves are used for medicinal purposes. These are harvested in June from a 3- to 4-year-old skullcap plant.
Chinese skullcapThe root is used medicinally.
Available Forms
American skullcap is available as a powder or liquid extract.
Chinese skullcap is available as a powder.
How to Take It
PediatricNeither American skullcap nor Chinese skullcap is recommended for children.
AdultSkullcap is available as an encapsulated dried herb, tea, fluid extract, and tincture. Speak to your physician to find the right form and dose for your needs.
Chinese skullcap is often combined with other herbs into a preparation; follow dosing recommendations on the label.
Precautions
The use of herbs is a time-honored approach to strengthening the body and treating disease. However, herbs can trigger side effects, and can interact with other herbs, supplements, or medications. For these reasons, you should take herbs with care, under the supervision of a health care provider.
American skullcap- In the past, American skullcap has been contaminated with germander (Teucrium), a group of plants known to cause liver problems. It is important that American skullcap be obtained from a reliable source.
- High doses of the tincture may cause giddiness, stupor, mental confusion, twitching, irregular heartbeat, and seizures.
- American skullcap should not be used during pregnancy and breastfeeding.
- If you have diabetes, DO NOT take Chinese skullcap without your doctor's supervision. Chinese skullcap may lower blood sugar levels, raising the risk of hypoglycemia (low blood sugar).
- Avoid Chinese skullcap if you have stomach or spleen problems.
- Chinese skullcap should not be used during pregnancy or breastfeeding.
Possible Interactions
If you are being treated with any of the following medications, you should not use either American skullcap or Chinese skullcap without first talking to your health care provider.
SedativesBoth American skullcap and Chinese skullcap can increase the effect of drugs that have a sedating effect, including:
- Anticonvulsants, such as phenytoin (Dilantin) and valproic acid (Depakote)
- Barbiturates
- Benzodiazepines, such as alprazolam (Xanax) and diazepam (Valium)
- Drugs to treat insomnia, such as zolpidem (Ambien), zaleplon (Sonata), eszopiclone (Lunesta), and ramelteon (Rozerem)
- Tricyclic antidepressants, such as amitriptyline (Elavil)
- Alcohol
The same is true of herbs with a sedating effect, such as valerian, kava, and catnip.
Drugs for DiabetesChinese skullcap can lower blood sugar, and could strengthen the effects of drugs taken for diabetes, increasing the risk of hypoglycemia (low blood sugar).
Supporting Research
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Enomoto R, Suzuki C, Koshiba C, et al. Wogonin prevents immunosuppressive action but not anti-inflammatory effect induced by glucocorticoid. Ann NY Acad Sci. 2007;1095:412-417.
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Gao Z, Huang K, Xu H. Protective effects of flavonoids in the roots of Scutellaria baicalensis Georgi against hydrogen peroxide-induced oxidative stress in HS-SY5Y cells. Pharmacol Res. 2001;43:173-178.
Huang RL, Chen CC, Huang HL, et al. Anti-hepatitis B virus effects of wogonin isolated from Scutellaria baicalensis. Planta Med. 2000;66:694-698.
Ikemoto S, Sugimura K, Yoshida N, et al. Antitumor effects of Scutellariae radix and its components baicalein, baicalin, and wogonin on bladder cancer cell lines. Urology. 2000;55:951-955.
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Lohani M, Ahuja M, Buabeid MA, et al. Anti-oxidative and DNA protecting effects of flavonoids-rich Scutellaria lateriflora. Nat Prod Commun. 2013;8:1415-1418.
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Shin HS, Bae MJ, Jung SY, Shon DH. Inhibitory effect of skullcap (Scutellaria baicalensis) extract on ovalbumin permeation in vitro and in vivo. Food Chem. 2013;140:22-30.
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Review Date: 1/1/2017
Reviewed By: Steven D. Ehrlich, NMD, Solutions Acupuncture, a private practice specializing in complementary and alternative medicine, Phoenix, AZ. Review provided by VeriMed Healthcare Network. Also reviewed by the A.D.A.M. Editorial team.
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