The properties of Woad
Isatis Tinctoria has been used in traditional Chinese medicine since ancient times. Its leaves and roots, known as Daqingye and Banlangen, respectively, are frequently used as anti-leukemia, antipyretic, anti-inflammatory and anti-influenza agents. Many compounds have been isolated from Isatis Tinctoria, including indigotin, indirubin, isatin, isatan A, isatan B, trytanthrin, purin, isaindigotidione, organic acids and a variety of amino acids. The biological activity of indigotin and indirubin has been reported, which are used as the markers for quality control due to their unique pharmaceutical activities. The Isatis indigotica root and phenolic Chinese herbs were frequently used for the prevention of severe acute respiratory syndrome (SARS) during the SARS outbreaks in China, Hong Kong, and Taiwan in 2003(1047).
Isatidis folium is a flowering plant belonging to the family Brassicaceae. The leaves of Isatidis Folium are traditionally used for the treatment of sore throat, redness of skin, and as an antipyretic. Isatidis Folium has also been used to treat encephalitis, acute dysentery, hepatitis, measles, pneumonia, influenza, epidemic cerebrospinal meningitis, encephalitis B, viral pneumonia, mumps, and diabetics. Tryptanthrin, an alkaloid isolated from Isatidis leaves, has shown anti-inflammatory effect due to its strong inhibitory effect on the COX-2 enzyme. Several derivatives of hydroxycinnamic acid, including ferulic acid and sinapic acid, are also thought to be important to inhibit inflammation. Isatidis Folium possesses valuable viricidal effect in the control of pseudorabies infection in swine.
Isatidis radix belongs to the family Brassicaceae. Traditionally, it used to cool blood. The dry root of Isatidis Radix has many pharmacological activities such as antibiotic, anti-diabetic, and immune-stimulating effects and is used to treat encephalitis B and viral infections. Methanolic extracts of Isatidis Radix can significantly inhibit the release of inflammatory mediators from the macrophages, such as NO, PGE2, and pro-inflammatory cytokines. Isatidis Radix has also been demonstrated to suppress the growth of E. coli and H. pylori and increases blood neutrophil phagocytosis of 32P-labeled Sta. aureus. Syringic acid isolated from Isatidis Radix inhibited LPS-induced endotoxin shock. Besides, Isatidis Radix is found to be clinically effective against the infections caused by various subtypes and strains of influenza viruses including Severe Acute Respiratory Syndrome (SARS)(1024).
Isatis Tinctoria root and phenolic Chinese herbs were frequently used for the prevention of SARS during the SARS outbreaks in China, Hong Kong, and Taiwan. I. indigotica root (Radix isatidis), belonging to the family Cruciferae, is native to China. Antiviral effects of Isatis Tinctoria root were found against influenza, hepatitis A and Japanese encephalitis. Isatis Tinctoria root contains indigo, indirubin, indican (indoxyl-β-d-glucoside), β-sitosterol, γ-sitosterol, sinigrin, etc. Indigo and indirubin were identified as the promiscuous chymotrypsin inhibitors. Recently, an anti-influenza virus effect of indirubin has been demonstrated. In addition, several herb-derived phenolics aloeemodin, hesperetin, quercetin, and naringenin have been accredited with antiviral effects against poliovirus, vesicular stomatitis virus, Sindbis virus, herpes simplex virus types 1 and 2, parainfluenza virus, and vaccinia virus(1046).