How It Works
Bottom Line:Scutellaria baicalensis has been used in traditional medicine to treat many medical conditions. Studies on its anticancer effects are underway.
Scutellaria baicalensis, also known as Huang Qin or Chinese skullcap, is a root extract used in traditional medicine, often in combination with other herbs. Scientists are not sure exactly how it works; it has been studied to some extent in the laboratory, but not in humans. Isolated liver cancer and leukemia cell lines, when exposed to extracts from this herb, undergo apoptosis (cell death). The extracts also reduce inflammation, act as antioxidants, and kill gram-positive bacteria in the laboratory setting. In animals, the extracts help lower blood cholesterol levels under certain conditions. However, it is not yet clear if any of these effects occur in the human body.
Purported Uses
To treat atherosclerosis
Studies in animals show that extracts of this herb may help lower blood cholesterol levels under certain conditions, but there is no proof from clinical trials that this effect occurs in the human body.
To treat cancer
Extracts from this herb cause cell death in isolated liver cancer and leukemia cell lines in the laboratory setting, but there is no proof that this herb can treat cancer in humans.
To treat hepatitis
The herbal formulation sho-saiko-to, which contains Huang Qin, has been studied for its possible liver-protectant effects.
To reduce inflammation
Limited laboratory data support this use, but there is no proof from clinical trials that this effect occurs in humans.
Research Evidence
Scutellaria baicalensis has not been studied in clinical trials as a single agent, but only in combination with other herbs in formulations such as
PC-SPES and
sho-saiko-to. (Please see these monographs for more information).
Warnings
Some products that contain scullcap have been found to be contaminated with a similar-looking plant known as germander (Teucrium chamaedrys), which can cause liver damage.
This product is regulated by the FDA as a dietary supplement. Unlike approved drugs, supplements are not required to be manufactured under specific standardized conditions. This product may not contain the labeled amount or may be contaminated. In addition, it may not have been tested for safety or effectiveness.
Do Not Take If
You are taking warfarin or other blood thinners (scullcap can increase the risk of bruising and bleeding).
Side Effects
Liver damage (it is not known whether this is caused by contamination, or by the herb itself);
Pneumonitis (inflammation of the lung due to bacterial or viral infection);
Stupor, confusion, and seizures have been reported in high doses.
Scientific Name
Scutellaria baicalensis
Common Name
Huang Qin, baikal skullcap, Chinese skullcap
Clinical Summary
Scutellaria baicalensis is an used in traditional Chinese medicine to treat a variety of conditions including epilepsy, hepatitis, infections, and cancer. It often is found in combination with other botanicals (e.g. PC-SPES and Sho-saiko-to). In vitro and limited animal data suggest that its bioflavonoid components cause apoptosis in hepatoma cell lines, but additional research is necessary
(2) (3). The flavonoid components of this plant also possess neuroprotective capabilities as seen in vivo Parkinson's and Alzheimer's disease models, possibly through reducing inflammation and oxidative stress
(4) (5). In addition, sedative and anticonvulsant effects have been reported using in vivo models
(6). Signs of toxicity include stupor, confusion, and seizures
(7).
Purported uses
Atherosclerosis
Cancer treatment
Epilepsy
Hepatitis
Infections
Inflammation
Insomnia
Constituents
Flavonoids: Baicalin, baicalein, scutellarein, wogonin, apigenin, hispidulin, luteolin, scutellarein
Iridoids: Catalpol
Volatile oils: Limonene, terpineol, beta-humulene, caryophyllene
Others: Lignin, resin, tannin
(8) (9)
Mechanism of Action
In vitro studies suggest that flavonoid components of this plant has anticancer activity. Induction of apoptosis in hepatoma G2, 3B, and SK-Hep1 cell lines occurs following 48 hours of exposure to baicalein, baicalin, and wogonin at concentrations of 25-100 mcg/ml. Wogonin causes arrest at G1 phase while baicalin and baicalein cause G2/M accumulation (2). Additional in vitro studies show baicalin at concentrations of 50-200 mcg/ml activates caspase-3, resulting in apoptosis of Jurkat cells (leukemia-derived T cells). Baicalin also exhibits anti-inflammatory, antioxidant, and gram-positive antibacterial activity in vitro (3). The neuroprotective effects of flavinoids from this plant were ameliorated by diazepam, a GABAA receptor agonist, suggesting that the components influence GABA receptor activity (5). The flavonoids also prevent ethanol-induced hyperlipidemia, histamine release from mast cells, and catecholamine-induced lipolysis in animal models (8).
Pharmacokinetics
Urinary pharmacokinetic analysis of baicalein, wogonin, and their glycosides in humans indicated that excretion of conjugated metabolites of wogonin was greater than those of baicalein (11.6 versus 7.2% of the dose)
(10). The low recovery of both compounds may be due to bile excretion or metabolism by enteric bacteria. In addition, in vitro studies revealed that baicalein is capable of crossing the gut epithelium as well as the blood-brain barrier
(11).
Warnings
Products have been found to be contaminated with a similar-looking plant known as germander (
Teucrium chamaedrys) that can cause hepatitis
(8).
Adverse Reactions
Reported: Hepatotoxicity, pneumonitis
(7)Toxicity: Stupor, confusion, seizures
(8)
Herb-Drug Interactions
Anticoagulants / Antiplatelets: May cause additive effects
(12).
Literature Summary and Critique
Scutellaria baicalensis has been studied in combination with other botanicals in formulations such as PC-SPES and sho-saiko-to.
References
1. Bonham M, Posakony J, Coleman I, Montgomery B, Simon J, Nelson PS.
Characterization of chemical constituents in Scutellaria baicalensis with antiandrogenic and growth-inhibitory activities toward prostate carcinoma. Clin Cancer Res 2005;11(10):3905-14.
2. Chang WH, Chen CH, Lu, FJ.
Different effects of baicalein, baicalin, and wogonin on mitochondrial function, glutathione content and cell cycle progression in human hepatoma cell lines. Planta Medica 2002;68:128-32.
3. Ueda S, Nakamura H, Masutani H, et al.
Baicalin induces apoptosis via mitochondrial pathway as prooxidant. Molecular Immunology 2002;38:781-91.
4. Cheng Y, He G, Mu X, et al.
Neuroprotective effect of baicalein against MPTP neurotoxicity: Behavioral, biochemical and immunohistochemical profile. Neurosci Lett. Aug 15 2008;441(1):16-20.
5. Kim DH, Kim S, Jeon SJ, et al.
The effects of acute and repeated oroxylin A treatments on Abeta(25-35)-induced memory impairment in mice. Neuropharmacology. Jul 10 2008. 6. Park HG, Yoon SY, Choi JY, et al.
Anticonvulsant effect of wogonin isolated from Scutellaria baicalensis. Eur J Pharmacol. Nov 28 2007;574(2-3):112-119.
7. Takeshita K, Saisho Y, Kitamura K, et al.
Pneumonitis induced by Ou-gon (scullcap). Internal Medicine 2001;40:764-8.
8. Newall CA, Anderson LA, Phillipson JD. Herbal Medicines: A Guide for Health-Care Professionals. 1st ed. London: Pharmaceutical Press; 1996.
9. Huang KC. The Pharmacology of Chinese Herbs. 2nd ed. New York: CRC Press; 1999.
10. Lai MY, Hsiu SL, Chen CC, Hou YC, Chao PD.
Urinary pharmacokinetics of baicalein, wogonin and their glycosides after oral administration of Scutellariae Radix in humans. Biol Pharm Bull. Jan 2003;26(1):79-83.
11. Tarrago T, Kichik N, Claasen B, Prades R, Teixido M, Giralt E.
Baicalin, a prodrug able to reach the CNS, is a prolyl oligopeptidase inhibitor. Bioorg Med Chem. Apr 29 2008.
12. Brinker F. Herb Contraindications and Drug Interactions. 3rd ed. Sandy (OR): Eclectic Medical Publications; 2001.
