RT Journal Article SR Electronic T1 Concentration-dependent Effect of Rikko-san on the Prostaglandin E2 Production by Mouse Macrophage-like Cells JF In Vivo JO In Vivo FD International Institute of Anticancer Research SP 491 OP 497 VO 20 IS 4 A1 NORIO HORIE A1 KEN HASHIMOTO A1 TAKAO KATO A1 TETSUO SHIMOYAMA A1 TADAYOSHI KANEKO A1 KAORU KUSAMA A1 HIROSHI SAKAGAMI YR 2006 UL http://iv.iiarjournals.org/content/20/4/491.abstract AB Rikko-san (RKS) and its ingredients were investigated for their activity to stimulate prostaglandin E2 (PGE2) production by unstimulated and lipopolysaccharide (LPS)-stimulated mouse macrophage-like Raw 264.7 cells. LPS significantly stimulated the production and extracellular secretion of PGE2 by Raw 264.7 cells. RKS dose-dependently modified the LPS-stimulated PGE2 production. A lower concentration (0.04-0.4 mg/ml) of RKS stimulated PGE2 production without or with LPS, whereas a higher concentration (4 mg/ml) of RKS inhibited the LPS-stimulated PGE2 production, suggesting the presence of both stimulator(s) and inhibitor(s) for PGE2 production. The inhibitory effect of a higher concentration of RKS was slightly neutralized by supplementation of exogenous arachidonic acid. Among five RKS ingredients, Kanzo inhibited the LPS-stimulated PGE2 production to the greatest extent, whereas other ingredients (Shoma, Ryutan, Saishin, Bofu) stimulated PGE2 production. Western blot analysis demonstrated that RKS and all its ingredients enhanced the intracellular concentration of cyclooxygenase-2, whereas RKS did not significantly affect the phospholipase A2 protein level. The present study demonstrates that the concentration-dependent effect of RKS on the PGE2 production by macrophage cannot be explained only by the expression levels of cyclooxygenase-2 or phospholipase A2.