Effect of Scutellariae radix ingredients on prostaglandin E(2) production and COX-2 expression by LPS-activated macrophage.

We previously reported that Sairei-to concentration- dependently modified lipopolysaccharide (LPS)-stimulated prostaglandin E 2 (PGE 2 ) production in mouse macrophage- like RAW264.7 cells. Among twelve major ingredients of Sairei- to, Scutellariae radix inhibited the LPS-stimulated PGE 2 production to the greatest extent, followed by Zingiberis rhizoma, Glycyrrhizae radix, Atractylodis lanceae rhizoma and Pinelliae tuber. Scutellariae radix contained several major flavonoids such as baicalin, baicalein and wogonin. We investigated the effect of these flavonoids on PGE 2 production and COX-2 expression by LPS-activated RAW264.7 cells. Wogonin inhibited PGE 2 production most efficiently, followed by baicalein and then baicalin, in the same order as their membrane permeability. It was unexpected that wogonin and all other compounds would fail to inhibit the expression of COX-2 at both protein and mRNA levels, suggesting the importance of re-evaluating the point of action of wogonin. Sairei-to, one of the Kampo medicines, is composed of 12 major ingredients (Bupleuri radix, Pinelliae tuber, Scutellariae radix, Zizyphi fructus, Ginseng radix, Glycyrrhizae radix, Zingiberis rhizoma, Cinnamomi cortex, Atractylodis lanceae rhizoma, Hoelen, Polyporus and Alismatis rhizoma), and has been used for the treatment of dermatitis or mucositis such as systemic lupus erythematosus, an autoimmune disease. We previously proposed that Chinese medicines can be separated into two groups (Groups I and II), based on their actions on nitric oxide (NO) production by activated macrophages. Sho-saiko-to, Hange-shashin-to and Sairei-to (tentatively classified as Group I) significantly reduced the extracellular concentration of NO in the lipopolysaccharide (LPS)-stimulated mouse macrophage-like RAW264.7 cells