Baical skullcap (Scutellaria baicalensis)

Traditional Indications

Baical skullcap is anondyne, anti-allergic, antibacterial, anticoagulant, anti-inflammatory, anti-microbial, antioxidant, antispasmodic, diuretic, expectorant, hypocholesterolaemic, nervine, sedative and vasodilatory. Baical skullcap is considered to be one of the 50 fundamental herbs in Traditional Chinese Medicine (TCM) and is used primarily in treating "hot and damp" conditions such as dysentery and diarrhoea. It has been used medicinally for over 2,000 years and recent research has found that the roots contain flavonoids that greatly enhance liver function and also have anti-inflammatory and anti allergenic effects (1).

In TCM baical skullcap is known as Huáng qín. Huáng qín in bitter and cold and enters the Gallbladder, Large Intestine, Lung and Stomach channels. Huáng qín clears heat and drains fire in the Upper Jiao and is indicated for fever, irritability, thirst and cough. Huáng qín clears Stomach Heat and dries Damp and is indicated for diarrhoea, dysentery, thirst with no desire to drink, Lin syndrome (urinary tract infections) and jaundice. Huáng qín clears Heat and is used to stop bleeding, heamoptemesis, nosebleed and blood in stool. Huáng qín is also said to clear Heat and calm foetus and is prescribed for restless foetus due to heat. Huáng qín sedates Liver Yang and treats headache, irritability, red eyes bitter taste and halitosis (2).

Pharmacognosy

Scutellaria baicalensis contains the active constituents include the flavonoids baicalein and baicalin (3). Baicalein and Baicalin are flavones, a type of flavonoid, originally isolated from the roots of Chinese skullcap (Scutellaria baicalensis) and skullcap (Scutellaria lateriflora) (4). Baicalein and baicalin inhibit colon cancer using two distinct fashions of apoptosis and senescence (5). Baicalein and baicalin are potent inhibitors of angiogenesis: Inhibition of endothelial cell proliferation, migration and differentiation (6).
Baicalein is a strong iron chelator under physiological conditions and hence may play a vital role in modulating the body's iron homeostasis (7).
Baical Skullcap has been widely used as a dietary ingredient and traditional herbal medicine owing to its anti-inflammatory and anti-mutagenic properties. The anti-allergic effects of skullcap and its active compounds, were examined and the active compound wogonin was found to significantly inhibit the inflammatory cytokine interleukin (IL)-4 (8). Radix scuttelaria has been found in clinical trials to inhibiting halitosis-correlated bacteria (9).

Baicalin exhibits biphasic effects on sleep-wake regulation; the decrease of SWS during the light period and increases of SWS and REMS during the dark period. Inhibition of IL-1 action and enhancement of GABA (A) receptor activity may mediate baicalin's effects during the light and dark period, respectively (10).

Scientific evidence supports the use of baical skullcap for allergies such as asthma, allergic rhinitis (hay fever), eczema and urticaria. Skullcap administration significantly inhibited T Helper cells 17 cytokine (IL-17), and Th2-related cytokines (IL-4, IL-5, IL-10, and IL-13), which increase with food allergy (11). Herbal compounds in Scut baicalensis were demonstrated to induce vasoconstriction and proved effective in relieving patients’ nasal congestion and was statistically superior to placebo (12).

The active constituent in skullcap, Skullcap flavone II inhibits airway inflammation in a mouse model of asthma (13).

A study has found chemical and pharmacological evaluations on the extract of Scutellaria baicalensis show S. baicalensis inhibits cytochrome P450 Phase II liver enzymes this is desirable in bioaccumulation and persistent organic pollutant overload. The active consituents of Scutellaria baicalensis, baicalein and baicalin, both have broad anti-tumour activity in vivo and are regarded as a potent anticancer agent (5, 14).

Baicalin, has a potential therapeutic effect against SARS-CoV-2 infection. Baicalin exhibits a significant inhibitory effect on PLpro and Mpro/3CLpro of SARS-CoV-2, possibly by direct binding on the catalytic site of these enzymes. Moreover, baicalin has potential on manipulating inflammation-related pathways that possibly diminishing the cytokine storm syndrome which may occur in severe cases of COVID-19. Our findings suggested that continuous research is needed to develop baicalin as a supportive treatment therapeutic for COVID-19.Our study indicated that baicalin, a natural compound that has been used in traditional Chinese medicine with minimal side effects, has a potential therapeutic effect against SARS-CoV-2 infection (15).

In 2019 Clinicaltrails.gov describe a designed by randomised, double-blind, placebo controlled, multicentre and phase Ⅱa clinical trial in order to evaluate the Baicalein tablets' safety and efficiency for adults with influenza (16).

The cytokine storm (CS) is a systemic inflammatory syndrome and a major cause of multi-organ failure and even death in COVID-19 patients. A study published in Frontiers in Pharmacology evaluated the therapeutic mechanism of baicalin against CS and to detect key targets of CS that may bind closely to baicalin through molecular docking found that mitogen-activated protein kinase 14 (MAPK14), IL2, FGF2, CASP3, PTGS2, PIK3CA, EGFR, and tumour necrosis factor (TNF) were the core targets. Baicalin was found to have bound most closely to TNF through molecular docking, and baicalin was demonstrated to effectively inhibit the elevation of TNF-α in vitro and in vivo. Furthermore, the study concluded that TNF and IL-17 signalling pathways may be potential key pathways for baicalin to treat CS (17).

1. PFAF. Scutellaria baicalensis 2019 [Available from: https://pfaf.org/user/Plant.aspx?LatinName=Scutellaria+baicalensis.
2. Lotus S. Huang Qin (Baical Skullcap Root) 2019 [Available from: https://www.sacredlotus.com/go/chinese-herbs/substance/huang-qin-baical-skullcap-root.
3. Zhao Q, Chen X-Y, Martin C. Scutellaria baicalensis, the golden herb from the garden of Chinese medicinal plants. Science Bulletin. 2016;61(18):1391-8.
4. You J, Cheng J, Yu B, Duan C, Peng J. Baicalin, a Chinese Herbal Medicine, Inhibits the Proliferation and Migration of Human Non-Small Cell Lung Carcinoma (NSCLC) Cells, A549 and H1299, by Activating the SIRT1/AMPK Signaling Pathway. Medical science monitor : international medical journal of experimental and clinical research. 2018;24:2126-33.
5. Dou J, Wang Z, Ma L, Peng B, Mao K, Li C, et al. Baicalein and baicalin inhibit colon cancer using two distinct fashions of apoptosis and senescence. Oncotarget. 2018;9(28):20089-102.
6. Liu J-J, Huang T-S, Cheng W-F, Lu F-J. Baicalein and baicalin are potent inhibitors of angiogenesis: Inhibition of endothelial cell proliferation, migration and differentiation. 2003;106(4):559-65.
7. Perez CA, Wei Y, Guo M. Iron-binding and anti-Fenton properties of baicalein and baicalin. Journal of Inorganic Biochemistry. 2009;103(3):326-32.
8. Shin HS, Bae MJ, Choi DW, Shon DH. Skullcap (Scutellaria baicalensis) extract and its active compound, wogonin, inhibit ovalbumin-induced Th2-mediated response. Molecules (Basel, Switzerland). 2014;19(2):2536-45.
9. Zhao X, He X, Zhong X. Anti-inflammatory and in-vitro antibacterial activities of Traditional Chinese Medicine Formula Qingdaisan. BMC complementary and alternative medicine. 2016;16(1):503-.
10. Chang H-H, Yi P-L, Cheng C-H, Lu C-Y, Hsiao Y-T, Tsai Y-F, et al. Biphasic effects of baicalin, an active constituent of Scutellaria baicalensis Georgi, in the spontaneous sleep–wake regulation. Journal of ethnopharmacology. 2011;135(2):359-68.
11. Shin HS, Bae MJ, Jung SY, Shon DH. Preventive effects of skullcap (Scutellaria baicalensis) extract in a mouse model of food allergy. Journal of ethnopharmacology. 2014;153(3):667-73.
12. Katotomichelakis M, Van Crombruggen K, Holtappels G, Kuhn FA, Fichandler CE, Kuhn-Glendye CA, et al. A herbal composition of Scutellaria baicalensis and Eleutherococcus senticosus shows vasocontrictive effects in an ex-vivo mucosal tissue model and in allergic rhinitis patients. 2017;3(1):21.
13. Jang HY, Ahn KS, Park MJ, Kwon OK, Lee HK, Oh SR. Skullcapflavone II inhibits ovalbumin-induced airway inflammation in a mouse model of asthma. International immunopharmacology. 2012;12(4):666-74.
14. Yu Y, Pei M, Li L. Baicalin induces apoptosis in hepatic cancer cells in vitro and suppresses tumor growth in vivo. International journal of clinical and experimental medicine. 2015;8(6):8958-67.
15. Lin C, Tsai FJ, Hsu YM, Ho TJ, Wang GK, Chiu YJ, et al. Study of Baicalin toward COVID-19 Treatment: In silico Target Analysis and in vitro Inhibitory Effects on SARS-CoV-2 Proteases. Biomedicine Hub. 2021;6(3):122-37.
16. ClinicalTrials.gov. A Randomized, Double-blind, Placebo-controlled, Multicenter and Phase Ⅱa Clinical Trial for the Effectiveness and Safety of Baicalein Tablets in the Treatment of Improve Other Aspects of Healthy Adult With Influenza Fever Bethesda, ‎Maryland, US: U.S. National Library of Medicine 2019 [Available from: https://clinicaltrials.gov/ct2/show/NCT03830684.
17. You J, Li H, Fan P, Yang X, Wei Y, Zheng L, et al. Inspiration for COVID-19 Treatment: Network Analysis and Experimental Validation of Baicalin for Cytokine Storm. Front Pharmacol. 2022;13:853496.