Scullcap Herb

Common Forms

Capsules: 300 mg, 425 mg, 429 mg

Liquid extract: 1 oz, 2 oz

Powder: 10 oz

Source

The leaves and roots of the plants Scutellaria laterifolia and Scutellaria baicalensis are prepared as hot water or methanolic extracts. Scullcap is native to temperate regions of North America.

Chemical Components

Scutellaria species contain flavonoids (apigenin, luteolin, hispidulin, scutellarein, scutellarin, baicalein, baicalin), an iridoid (catalpol), limonene, terpineol, carophyllene, cadinene, and other sesquiterpenes in the volatile oils. Wogonin, lignin, resin, and tannins are also present. Actions

Scullcap is believed to have anticonvulsant and sedative actions. An aqueous extract was found to have mild anthelmintic properties in vitro. Other studies found bacteriostatic or bactericidal effects in vitro. One study showed that concomitant Use of baicalin with several beta­lactam antibiotics lowered the minimum inhibitory concentrations when tested against MRSA .

A root extract of scull cap showed anti-inflammatory action by inhibiting interleukin-1 and inhibited the synthesis of prostaglandin E 2 and leukotriene B4 . Another study noted the inhibitory effects of scullcap flavonoids on sialidase-an agent associated with certain cancers-in mice. Scullcap extracts decreased 5-fluoro­uracil and cyclophosphamide myelotoxicity as well as tumor cell viability in mice .

The extracts (flavonoids) of scullcap have demonstrated antiviral effects against the influenza virus and human T-cell leukemia virus type 1. Investigators believe that the inhibitory effect of the extract is dose­dependent . Another agent, baicalin, inhibited both HIV-1 infection and replication in human peripheral blood cells . In vitro data suggest that scullcap may also inhibit EpsteinBarr virus early antigen activation.

Extracts from S. baicalensis decreased cardiomyocyte cell death after an ischemia-reperfusion experiment. The authors of the study suggested that baicalin’s protective effect could be attributed to the flavonoid’s ability to scavenge superoxide, hydrogen peroxide, and hydroxyl radicals .

Reported Uses

Scullcap has been used traditionally as an anticonvulsant, an anti­inflammatory, a cholesterol-lowering agent, and an agent for movement disorders and spasticity. Little, if any, information exists to support the use of this herb in humans.

Scullcap has also been used as an antiviral and has demonstrated some efficacy in animal studies in vitro. One study found that the addition of scullcap to chemotherapy prompted an increase in serum immunoglobulin levels in patients with lung cancer who were theophyl­line-resistant . In another study of patients receiving chemotherapy for lung cancer, the addition of a dry scullcap extract promoted hematopoiesis and an increase in the circulating precursors of erythroid and granulocyte colony-stimulating factors .

Other foreign reports in humans have suggested a role for scullcap in therapy of stroke and cerebral thromboembolism.

Dosage

Doses have been administered P.O., I.V., and LM.

Dried herb: 1 to 2 g as a tea P.O. t.i.d.

Liquid extract (1:1 in 25% alcohol): 2 to 4 ml P.O. t.i.d.

Tincture (1:5 in 45% alcohol): 1 to 2 ml P.O. t.i.d.

Adverse Reactions

GI: hepatotoxicity.

Excessive doses of tincture:

CNS: confusion, giddiness, seizures, stupor.

CV: arrhythmias.

Musculoskeletal: fasciculations.

Interactions

Disulfiram: Disulfiram reaction can occur if herbal form contains alcohol. Avoid concurrent use.

Immunosuppressants: May alter effect on serum immunoglobulin levels. Do not use with scullcap.

Contraindications and Precautions

Avoid using scullcap in pregnant or breast-feeding patients; effects are unknown.

Special Considerations

• Monitor liver function test results periodically.
• Advise the patient to avoid taking large doses of scullcap tincture because of possible toxicities.
• Inform the patient that commercial sources of scullcap have been found to be contaminated with other herbs.
• Inform the patient that insufficient evidence exists to recommend scullcap for any condition or disease.
• Advise women to avoid using scullcap during pregnancy or when breast-feeding.

Points of Interest

• Scullcap has been demonstrated to be adulterated with Teucrium species. Some species of Teucrium (T. chamaedrys-Germander) have also been linked with hepatotoxicity.

Commentary

Although several animal and in vitro studies have demonstrated the inhibitory effects of scullcap on pathologic viruses, there is little, if any, clinical trial evidence to support this application in humans. Furthermore, in vitro studies claiming antibiotic or cardioprotective properties have not been substantiated by human trials. Human studies have demonstrated some benefit of scull cap consumption in lung cancer, which points out the need for vigorous follow-up clinical investigation.

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