Inhibitors of inducible nitric oxide synthase expression fromartemisia iwayomogi

Abstract

Nitric oxide (NO) is an important bioactive agent that mediates a wide variety of physiological and pathophysiological events. NO overproduction by inducible nitric oxide synthase (iNOS) results in severe hypotension and inflammation. This investigation is part of a study to discover new iNOS inhibitors from medicinal plants using a macrophage cell culture system. Two sesquiterpenes (1 and 2) were isolated from Artemisia iwayomogi (Compositae) and were found to inhibit NO synthesis (IC50 3.64 microg/mL and 2.81 microg/mL, respectively) in lipopolysaccharide (LPS)-activated RAW 264.7 cells. Their structures were identified as 3-O-methyl-isosecotanapartholide (1) and iso-secotanapartholide (2). Compounds 1 and 2 inhibited the LPS-induced expression of the iNOS enzyme in the RAW 264.7 cells. The inhibition of NO production via the down regulation of iNOS expression may substantially modulate the inflammatory responses.

Phenolic Compounds from Artemisia iwayomogi and Their Effects on Osteoblastic MC3T3-E1 Cells

“…Additionally, 2 mM of compounds 7, 12, and 13 also induced 123, 115, and 125% increases in cell viability, respectively. Thus, in terms of structure-activity, coumarin types (3, 4), acetophenone types (7,8), tachioside (11), benzoic acid (12), and caffeic acid methyl ester (13) were apparently key functional elements determining cell viability.…”

“…5,6) Methanol extracts of A. iwayomogi inhibit nitric oxide production of lipopolysaccharide-activated macrophages 7) and two sesquiterpenes from A. iwayomogi were reported to inhibit the expression of inducible nitric oxide synthetase (iNOS). 8) In another study, MeOH extracts of A. iwayomogi scavenged peroxynitrite (ONOO Ϫ ), a potent cytotoxic oxidant formed by the reaction of nitric oxide (NO) with superoxide radical (O 2Ϫ ). 9) Additionally, an aqueous extract of A. iwayomogi prevented immediate-type allergic reactions and inflammatory cytokine secretions in mast cells.…”

Chemical Composition and Antibacterial Activity Against Oral Bacteria by the Essential Oil of Artemisia iwayomogi

“…Moreover, two sesquiterpenes isolated from A. iwayomogi are identified as inhibitors of iNOS expression in LPSactivated macrophages (1). The polysaccharide fraction AIP1 from A. iwayomogi suppresses apoptotic death of the mouse spleen cells in culture (11).…”

Immunostimulatory and Anti-inflammatory Polysaccharides fromTripterygium wilfordii.: Comparison with Organic Extracts

“…The ethyl acetate extract of T. wilfordii possessed a strong inhibition against LPS-induced NO production in macrophages (IC 50 1.7 µg/mL) equal to or stronger than organic extracts prepared from other plants such as from Ginkgo biloba L. (IC 50 100 µg/mL; Kobuchi et al, 1997) and Artemisia iwayomogi Kitamura (two sesquiterpenes with IC 50 values of 3.6 and 2.8 µg/mL, respectively) (Ahn et al, 2003). Similarly, EA compared favorably with furanocoumarins from various plants (IC 50 9.8-19.5 µg/mL) (Wang et al, 2000), natural sesquiterpenoids from plants of the Zingiberaceae (IC 50 1.0-4.6 µg/mL) (Lee et al, 2002), a gallate compound from the root of Paeonia lactiflora Pall.…”