Effect of Scutellariae radix (Huangqin) on preventing rhinovirus-provoked asthmatic inflammation in cultured human bronchial epithelia.

Scutellariae radix (SR), also known as Huangqin, is the dried root of Scutellaria baicalensis Georgi (Lamiaceae). It is listed in the Chinese Pharmacopoeia and is one of the most widely used Chinese herbal medicines against bacterial infection of the respiratory and the gastrointestinal tracts. The main components of SR (and of all Scutellaria species) are baicalein, baicalin, and wogonin. Rhinovirus (RV) infection is the major cause of common colds and the most frequent trigger (up to 85%) for asthma exacerbation.1 The cellular mechanism by which viral respiratory infections may induce asthma is complex. The bronchial epithelium is the primary target for respiratory viral infections. The viruses must pass through the epithelial barrier to enter the body. At the same time, the viruses infect and replicate in the bronchial epithelial cells. Such infection is associated with airway inflammation, which is partly due to the major basic protein (MBP), a product of the eosinophils. The MBP is increased in upper respiratory viral infections associated with asthma exacerbations,2 causing virus-induced cellular damage. The airway surface epithelium itself is responsible for the synthesis and release of cytokines that cause the selective recruitment, retention, and accumulation of various inflammatory cells.3 Certain inflammatory cytokines alter the fluid and electrolyte transport of the airway epithelium. Therefore, asthma can be considered a disease of the bronchial epithelium, which could contribute to the pathophysiology of airway inflammation. Damage of the surface airway epithelium in Hong Kong Med J 2014;20(Suppl 4):S34-6 RFCID project number: 10090872 WH Ko *, Y Huang