Introduction

Scutellaria baicalensis, also known as “Chinese skullcap” or “Huang Qin,” is a root extract that has been used in both traditional Chinese and Japanese medicine for centuries.

Skullcap is also widely used as a backbone in herbal formulas in the western world, where it is often referred to as “scute.”

Skullcap is believed to have cardio-protective, relaxant, anti-anxiety, anti-inflammatory, antioxidant, and antibacterial properties and is purported to relieve menstrual cramping and tension headaches.

It is generally thought that skullcap is poorly researched, but let’s look at what research there is on this commonly used herbal medicine.

What Is Skullcap?

Skullcap is a plant of the Lamiaceae or mint family. Related but different forms of Scutellaria are used in different healing traditions. Scutellaria baicalensis is used in Chinese medicine, while Scutellaria lateriflora is used in western herbalism.

Scutellaria contains bioactive compounds, including flavonoids and phenols. Two key related bioactive compounds in skullcap are baicalen and baicalein, which are generally considered to be potent anti-inflammatories.

Skullcap is frequently used in formulations for respiratory conditions in both traditional eastern medicine and western herbal medicine.

Skullcap is a key component in a Japanese and Chinese herbal formation known as Kampo (Tsumara saiboku or TJ-96). Kampo is often used as a steroid-sparing agent.

In general, skullcap is poorly water soluble and, for this reason, skullcap tinctures are preferred to teas.

Is There Any Research?

There are over 1,700 papers on skullcap, including 25 clinical trials. To put this into context, there are over 200 published clinical trials on lavender.

Does Skullcap Fight Cancer Cells?

There are three clinical studies looking at the effect of skullcap in cancer. Two of these studies were done in the laboratory but were based on patient-derived cancer cells, while just one study was done on patients.

The first study looked at cancer cells from children with acute lymphocytic leukemia. Baicalin from an extract of Scutellaria baicalensis was noted to increase the killing of cancer cells (apoptosis) and the overall immune function of T-cells derived from these children (1).

The second study was a phase-one pre-clinical study done on breast cancer cells where skullcap was found to induce cell death in the breast cancer cells (2).

This encouraging preclinical data was followed by a study in Hollywood, which looked at 2,700 women with confirmed metastatic breast cancer who were heavily pretreated with chemotherapy (3). These women were treated with four different doses of Scutellaria barbata. It was found that the Scutellaria was safe, well tolerated, and showed some promising clinical anticancer activity.

Bottom Line

It is too early to say if skullcap has significant anticancer activity at this time.

Does It Calm Anxiety?

There are two clinical trials looking at the effect of Scutellaria on anxiety and mood.

This first was a placebo-controlled, double-blind, crossover study in 43 healthy volunteers in the UK (4). The study participants were randomized to Scutellaria lateriflora 350 milligrams or a placebo daily for two weeks. The study found a statistically significant decrease in anxiety in volunteers treated with skullcap, but not in the placebo group.

Additionally, Scutellaria lateriflora enhanced global mood, but without a reduction in energy or cognition. The researchers concluded that Scutellaria may have a valuable role to play in subjects with anxiety.

The second study reports positive benefits of skullcap on mood in healthy volunteers (5). There is only an abstract available for this study and, as such, it is not possible to assess the quality of the data in this study.

Bottom Line

There is a single study suggesting that skullcap can play a role in calming anxiety.

Does It Reduce Inflammation?

There is one clinical trial looking at the anti-inflammatory effects of skullcap. The study was done in 79 men and women in Florida who had a diagnosis of mild to moderate osteoarthritis (6). Study subjects received either naproxen as pain relief, or a combination of Scutellaria baicalensis and Acacia catechu (UP446) daily for a week.

The study found that both the naproxen and UP446 group experienced reduced pain, but only the UP446 group reported an enhanced ability to endure more rigorous activities. The authors of the study observed that they could not offer an explanation for this observation, and considered it counter-intuitive.

Considering the fact that both agents reduced pain, they expected that both groups should have an enhanced exercise tolerance, but that was not the case. The authors of the study recommend that further studies are done to specifically look at the effects of UP446 on mobility.

The study found no change in the levels of pro-inflammatory markers such as CRP, IL-6, and IL-1b in either treatment group.

Bottom Line

Skullcap has a long history of use as an anti-inflammatory. The single clinical study looking at skullcap as an anti-inflammatory is inconclusive, and the topic needs further work.

Does It Help Insomnia?

There are no specific clinical trials evaluating the effect of skullcap on sleep and insomnia (7). There is one study from China which comments on the fact that Scutellaria radix root drug extract was noted to contain melatonin. Therefore, it is biologically plausible that Scutellaria could have a role in sleep.

Bottom Line

There is no clinical data to support the role of skullcap in sleep at present.

Does It Reduce Risk of Heart Disease?

There are no clinical trials evaluating the effect of skullcap on heart disease. Studies in rats show that Scutellaria improves vascular elasticity and stimulates catalase activity and thereby exerted a cardioprotective effect (8). It also improves myocardial contractility in rats with lipopolysaccharide-induced sepsis (9).

Bottom Line

There is currently no clinical evidence to support a role for Scutellaria in reducing the risk of heart disease.

Does It Lower Fevers Resulting From the Flu?

There are no human clinical trials looking at the effect of skullcap in influenza.

Studies of Huang Qin derived from the roots of Scutellaria baicalensis Georgi showed that it is more potent than the flu drug Tamiflu against laboratory strains of the H1N1 virus (10).

A second study identified that Scutellaria baicalensis Georgi exhibits anti-influenza A activity via induction of interferon-gamma (11).

The anti-influenza activity of skullcap was also confirmed in a more recent study using a new anti-neuraminidase assay in 2016 (12).

Bottom Line

There is preclinical but no clinical data to support the role of skullcap as an anti-influenza agent.

Does It Treat Epilepsy?

There are no human clinical trials looking at the effect of skullcap on epilepsy. A study showed that male rats with artificially induced epilepsy who were given a combination of three herbal fluid extracts (Scutellaria lateriflora, Gelsemium, and Jimson Weed ) remained seizure-free as compared to rats who just received tap water (13).

Further support for the role of skullcap in epilepsy comes from a laboratory-based study in Korea which suggests that the anticonvulsant activity of skullcap is mediated via the benzodiazepine binding site of GABA receptors and relates to a dihydroxy group present on the flavonoids of Scutellaria (14).

Bottom Line

There are no clinical studies to support the role of skullcap in epilepsy.

Is Skullcap Safe?

Single oral doses of 100-2,800 mg of baicalein extracted from skullcap have been shown to be safe and well tolerated by healthy subjects (15).

However, there are reports of adulteration of skullcap with Teucrium species, which is known to be hepatotoxic (16). It is therefore advisable to buy skullcap from a reputable company.

Skullcap is an inhibitor of the cytochrome P450 drug-metabolizing system and can cause toxicity if co-administered with other drugs metabolized by this pathway, e.g. some drugs used in HIV disease.

Like many other herbal medicines, skullcap can increase the risk of bleeding in people taking blood-thinning or anticoagulant therapies.

Skullcap can also decrease the effectiveness of lipid-lowering statin drugs.

Conclusion

The lack of quality research on skullcap makes it very difficult to take an informed stand on this herbal remedy for any indication.