Antioxidative and Anti-Inflammatory Activities of Polyhydroxyflavonoids of Scutellaria baicalensis GEORGI

The active ingredients of 'golden root' of <I>Scutellaria baicalensis</I> GEORGI (Huang-Qin), a valuable traditional Chinese medicine, are polyhydroxyflavonoids, namely baicalein, oroxylin A and wogonin. With the objective of overcoming their poor solubility and to investigate their structure and activity relationships, baicaleinyl 7-<I>O</I>-sulfate was prepared, and extensive comparative antioxidative and anti-inflammatory tests were conducted. All the polyhydroxyflavonoids exhibited significant antioxidative and free-radical scavenging activities. In respect of their nitric oxide (NO) inhibition, wogonin was superior to all the other flavonoids, while oroxylin A was most potent in the inhibition of lipid peroxidation. Wogonin proved to be the most potent (82.9% inhibition, <I>p</I><0.05) in its anti-inflammatory activity against carrageenan-induced rat hind paw edema. There was a correlation between the <I>in-vivo</I> anti-inflammatory activity and the <I>in-vitro</I> antioxidative activities.