Skullcap (Scutellaria baicalensis) is an herb used in Traditional Chinese Medicine primarily for cardiovascular and cognitive health and for bleeding disorders.
Skullcap (also referred to as Chinese skullcap) is rich in flavonoids — a diverse group of phytonutrients; regular consumption has been associated with reduced risk of a number of chronic diseases, including cancer, cardiovascular disease and neurodegenerative disorders (1).
The flavonoids wogonin and baicalein have been identified as the main active ingredients of Scutellaria baicalensis. These bioactives are mainly present in the roots.
Skullcap has neuroprotective properties. The flavonoid baicalein, isolated from skullcap, has been shown to be rich in antioxidants. As such, researchers propose that its use may help prevent oxidative stress — a disturbance in the balance between the production of damaging free radicals and protective antioxidants (2).
Oxidative stress has been implicated in the development of several diseases, including Parkinson’s disease.
In a recent study, researchers investigated the effect of baicalein in mice induced with MPTP (a chemical that causes the damage of dopaminergic neurons as seen in Parkinson’s disease) with promising results.
Pretreatment with baicalein for a week was followed by challenge with MPTP for four consecutive days. Results showed that baicalein possesses potent neuroprotective activity and may be a potential anti-Parkinson’s disease drug that warrants further study.
Some of the mechanisms of action include increasing the counts of dopaminergic neurons (the degeneration of the dopaminergic neurons in the brain is thought to play a key role in the development of Parkinson’s disease) and inhibiting oxidative stress (3,4).
Skullcap has anti-inflammatory effects. To assess the herb’s anti-inflammatory potential, researchers studied the mechanism underlying the attenuation of cigarette smoke-induced respiratory inflammation by baicalin.
In vivo, mice were exposed to smoke of 15 cigarettes for 1 h/day, 6 days/week for 3 months and dosed with baicalin or dexamethasone. In vitro, human lung cells were incubated with baicalin or dexamethasone followed by treatments with cigarette smoke extract or TNF-α or trichostatin A.
Researchers found that baicalin significantly protected pulmonary function and attenuated cigarette smoke-induced inflammatory response by decreasing inflammatory cells and production of TNF-α (a protein in the body that causes inflammation), Interleukin 8 (a proinflammatory chemokine) and MMP-9 (regulatory enzymes in pathways of inflammatory disorders; increased expression of MMPs has been demonstrated in almost all inflammatory diseases) 5.
Skullcap may be useful for the treatment of cognitive impairments. In a study published in Neurobiology of Learning and Memory, researchers set out to investigate the effects of oroxylin A (a skullcap flavonoid) on memory impairment.
Mice were drug-induced to simulate amnesia and subjected to the passive avoidance test, the Y-maze test and the Morris water maze test.
Oroxylin A (5 mg/kg) significantly reversed cognitive impairments in mice by passive avoidance and the Y-maze testing. Oroxylin A also improved escape latencies in training trials and increased swimming times and distances within the target zone of the Morris water maze (6).
Skullcap may have attention-promoting properties. In a rat model of attention-deficit hyperactivity disorder (ADHD), the flavonoid oroxylin A repressed ADHD-like behaviors (hyperactivity, impulsivity and inattention) 7.
Skullcap may play a future role in cancer treatment. Botanical preparations are widely used by many cancer patients as an adjuvant treatment for certain types of cancer. In their studies of the efficacy of skullcap in the treatment of prostate cancer, researchers found that Scutellaria baicalensis and four of its flavonoids — baicalein, wogonin, neobaicalein and skullcapflavone — were capable of inhibiting prostate cancer cell proliferation.
Individual compounds exhibited antiandrogenic activities with reduced expression of the androgen receptor and androgen-regulated genes (several diseases such as prostate cancer are associated with alterations in androgen receptor function).
In vivo, baicalein reduced the growth of prostate cancer xenografts in nude mice by 55 percent at 2 weeks compared with placebo and delayed the average time for tumors to achieve a volume of approximately 1,000 mm(3) from 16 to 47 days.
It is believed that the anticancer activity is through inhibition of the androgen receptor signaling pathway. Researchers are confident that further clinical studies evaluating the efficacy of skullcap and its flavonoids in the context of chemoprevention or cancer treatment are warranted (8).
While some cancer cell lines undergo cell death when exposed to extracts from this herb, according to Memorial Sloan Kettering Cancer Center, there are some compounds in this herb that may have opposite effects. Additional studies are needed to confirm the circumstances under which this herb may be beneficial when treating cancer (9).
Skullcap may help prevent the development of obesity-related disorders and fatty liver. In an animal study, several assessments were made in rats fed a high-fat diet with or without baicalin treatment. In addition to examining weight, researchers analyzed serum biochemical parameters, liver histology and lipid profiles to determine whether the animals were suffering from metabolic disorders or fatty liver.
Results revealed that after 16-weeks, baicalin treatment (80 mg/kg) suppressed body weight gain and reduced visceral fat mass.
In addition, treatment significantly decreased the elevated serum cholesterol, free fatty acid and insulin concentrations caused by the high-fat diet, and reduced liver lipid accumulation (10).
There have been some reports of liver damage and lung inflammation with use.
In a case report, patients experienced acute livery injury following consumption of a formula containing baicalin derived for osteoarthritis (11).
Skullcap should not be taken with anticoagulants, antiplatelets or statins (drugs taken to lower cholesterol levels in the blood).
There is a lack of human evidence to currently recommend an optimal dosage. Future studies will clarify the safest and effective doses.
Skullcap is an herb traditionally used in Chinese medicine for cardiovascular and cognitive health. Also known as Chinese skullcap and Scutellaria baicalensis, it is rich in flavonoid components, namely wogonin and baicalein. Other important flavonoids include neobaicalein, skullcapflavone and oroxylin A.
Skullcap’s neuroprotective, anti-inflammatory and antioxidant potential make it a promising candidate for the treatment and prevention of a range of other medical conditions. Early research shows it may treat cognitive impairments, ADHD and certain cancers. It may also help prevent the development of obesity-related disorders and fatty liver.
Further clinical studies and trials are needed to learn more about the short-term and long-term side effects as well as the optimal dosage. There have been some reports of liver damage with use.