Skullcap can be a little deceptive because there are two distinct varieties: American skullcap and Chinese skullcap. (1) Both belong to the Lamiaceae family of plants, but each variety may provide significantly different potential medicinal benefits in the body. Historically, American skullcap has been used for antioxidant support; supporting the brain, cognition, memory, mood and behavior. Alternatively, Chinese skullcap may be used to support the immune system, seasonal challenges, respiratory health, temporary relief from occasional pain, healthy blood sugar levels, and blood pressure already within the normal range.
The earliest known use of skullcap is believed to date back to China, around 1281 AD, when the physician Zhu Danxi of the Yuan Dynasty wrote about its use in Ancient Chinese medicine. (2) Herbalists who practiced medicine through Europe and much of the east suggested its use for the cardiovascular system, healthy aging, breathing disorders, and digestive challenges.
If using skullcap as a medicinal aid, ensuring which variety you choose is especially important, as taking the wrong herb may result in the absence of results or unwanted side effects. Continue reading to learn about the differences and similarities between these two varieties, and which of the two may be ideal for when seeking out herbal support for individual health and wellbeing.
What Is American Skullcap?
Scutellaria lateriflora, also known as American skullcap, blue skullcap, mad dog skullcap, and side-flowering skullcap, is a perennial herb that favors wetlands, marshes, meadows, and other moist habitats. The name skullcap comes from the shape of the flowers and seed capsules, described as resembling the helmets worn by the military in the Middle Ages. (3) It is native to North America but is now cultivated in Europe and has begun spreading to other areas of the world as demand grows. American skullcap can be found growing natively in areas between Quebec to British Columbia, south to California, and back east to Florida. (4)
American skullcap grows up to 3 feet tall and forms branches that square off from the central stem. The stem and branches are primarily green but can also present a reddish hue. The leaves are thin, smooth, and mostly grow opposite other leaves. They are around 3 inches long and 2 inches wide, are elongated in an oval shape with a lance-like point, and also have heart-like features. Their leaves show serrated edges and irregular veins. The flowers are often referred to as snapdragon-like for the appearance that is similar to a reptiles’ upper and lower jaw.
The flowers protrude forward with two distinct petals that curve and appear three dimensional when compared to the thin flower petals produced by many other plants. Skullcap flowers are typically blue, but may also appear violet or white. The lower petal is usually lighter. Up to 7 flowers grow in pairs along the roughly 6 inch stem, with auxiliary stems growing outward beneath each flower. They begin to bloom in the summer and fall, living about 2 months before being replaced by a seed pod that contains four nutlets. Flowers do not often bloom at the same time. The flowers are not aromatic and attract only a few insects and animals.
What Is Chinese Skullcap?
Scutellaria baicalensis, also known as Chinese skullcap, Huang Qun, and Haikal skullcap, is similar in many ways to American skullcap. Differences lie in the subtle change of appearance. Their leaves are not serrated and flower petals are more elongated. (5) Chinese skullcap is one of the 50 fundamental herbs in Traditional Chinese medicine. In this system of medicine, it is prescribed for “hot and damp” conditions such as inflammation, infection, and for calming the mind. (6) It is also suggested for a range of disorders in the liver, gastrointestinal tract, urinary tract, prostate, respiratory system, and joints. The root is the part of the plant that is used for medicinal purposes.
Skullcap is comprised of the natural plant compounds baicalin, wogonoside, oroxylin, neobaicalein, and a range of flavonoids and antioxidants that are found in smaller quantities. (7) The root structure contains the majority of these plant compounds. Most of these compounds are suggested to be readily absorbed in a healthy body, either through the cellular walls or when metabolized by intestinal microflora. These compounds have been researched and been found to provide support for the body in several days.
Baicalin, which is found in Chinese skullcap has been found to have a positive effect on HSP70, an element that helps to protect neurons from cell death that results from stroke, seizures, and other age-related diseases. (8)(9)
Oroxylin A, also from Chinese skullcap, has been shown to help regulate microglia activation. (10)(11) Microglia is a compound in the brain involved in mediating the secretion of inflammatory factors from the immune system. These results suggest that oroxylin A may be useful for helping to protect the brain from inflammation-related conditions. This compound has also been shown to be potentially beneficial to help address cognitive impairments resulting from nervous system dysfunctions. (12) These results have not yet been demonstrated on human subjects.
Chinese skullcap may also provide support for memory during normal aging. Ibotenic acid, a toxin that causes memory-related disorders, has been found to improve spatial cognition, memory impairments, and helped to protect cells from oxidative damage. (13)(14)
Relaxation, Mood, and Behavior
The compound baicalin in Chinese skullcap may help to support a healthy sleep cycle when administered during dark periods of the day. (15) During light periods, the effect of baicalin was found to be blocked by receptors in the brain that regulate the wake-sleep cycle.
When tested on human volunteers, American skullcap was found to “enhanced global mood without a reduction in energy or cognition,” but further studies are needed to understand the mechanisms by which it affects mood. (16)
When tested for its role in helping to mediate hyperactive and attention-related disorders, oroxylin A helped to inhibit chemicals in the brain that can lead to inattention and impulsivity. (17)
Chinese skullcap may help to maintain blood pressure already within the normal range. (18) Flavones derived from the root of the plant were shown to stimulate endothelial nitric oxide generation, which is important for the development of the smooth lining found inside of arteries and vessels. When under pressure, the ability for these arteries and vessels to expand and contract is essential for blood pressure regulation and a healthy heart.
Blood Glucose and Body Weight
Chinese skullcap may help to maintain blood sugar levels already within the normal range and support healthy weight management. (19)(20) Up to 400 mg/kg extracts of the herb were found to reduce insulin levels in the body during a 4 week period, which was similar to the effects of 500 mg/kg of the diabetes medication metformin; however, metformin has been shown to provide results more quickly than skullcap. Skullcap was also found to support metabolic processes that can lead to a reduction in body weight.
Flavonoids in Chinese skullcap activate the protein PPARa, which helps to mediate fatty acid synthesis and oxidation. The activation of PPARa is believed to help reduce body weight and the development of fat tissue. (21) (22)
Chinese skullcap helps to regulate the release of histamines, with one study showing that 100 micrograms per kilogram of body weight halved the number of histamines released in response to allergy-causing compounds. (23) It also helped to inhibit the immune system response, which resulted in a reduced inflammation response.
Scutellarein, a compound found in all varieties of skullcap, has been studied for potentially inhibiting the metastasis of cells in connective tissue. In lab cultures, scutellarein suppressed the proliferation rate of HT1080 fibrosarcoma cells by helping to increase cell death. (24) It also inhibited cell migration and invasion. More research, including human studies may be necessary to validate these results.
American skullcap has shown to offer neuroprotective mechanisms that may support feelings of anxiety and brain health during normal aging. (25) Extracts from skullcap have been found to protect against oxidative stress that can cause DNA fragmentation and lead to the degradation of healthy cellular development.
The root structure of the Scutellaria species has been found to be effective in the treatment of ulcerative colitis in animal studies. (26) Results in animal testing show “improved macroscopic and histological damage scores, and enhanced recovery of normal colonic secretory function.”
Skullcap Dosage, Warnings, and Interactions
There is no established safe dosage of skullcap. Supplements can contain roots, leaves, flowers, stems, or other plant parts in amounts that range from under 100 mg to over 1,000 mg. Several studies suggest that taking up to 4,000 mg may be ideal for a desired result; however, individual results may vary. Consult with a primary care physician before beginning a regime of skullcap.
Skullcap may interact with other drugs or therapies, so if changes to health occur immediately contact a primary care physician. An overdose of skullcap may cause erratic mood or behavior, including dizziness, confusion, twitching, irregular pulse, and symptoms similar to epilepsy. Following the manufacturer recommended dose is believed to reduce the risk of side effects related to overdosing. If side effects occur, immediately stop use and consult a primary care physician. Pregnant women should not use skullcap, and it should never be given to children unless under the supervision of a primary care physician.
Skullcap can be contaminated with germander, a species of plants that have been found to cause liver problems. (27) In some clinical cases, skullcap has been found to cause hepatotoxicity and acute liver failure. (28) In small case studies, jaundice (the yellowing of skin and eyes) has been found to arise after 1 to 3 months of starting a regime of either Chinese of American skullcap. It is currently not understood why liver damage occurs. If symptoms of liver damage occur stop use immediately.
Shopping for Skullcap
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