Effect of three herbal extracts on NO and PGE2 production by activated mouse macrophage-like cells

Three Chinese herbal extracts, Drynaria baronii, Angelica sinensis and Cornus officinalis Sieb. et Zucc (referred to as DB, AS, CO, respectively), were investigated for their possible anti-inflammatory activity. DB, AS and CO inhibited nitric oxide (NO) production by lipopolysaccharide (LPS)-activated mouse macrophage-like RAW264.7 cells. Western blot and RT-PCR analyses demonstrated that this was due to the inhibition of inducible NO synthase (iNOS) expression at both protein and mRNA levels. Electron-spin resonance spectroscopy showed that DB, AS and CO dose-dependently scavenged the NO radical produced by NOC-7 in the presence of carboxy-PTIO. In order to confirm the anti-inflammatory potency, effects on prostaglandin (PG) E(2) production and the expression of enzymes involved in the arachidonic acid pathway were next investigated. DB and CO effectively inhibited the PGE(2) production by LPS-stimulated RAW264.7 cells, although the extent of inhibition of PGE(2) production was slightly lower than that of NO production. AS only marginally inhibited the LPS-stimulated PGE(2) production. DB, AS and CO inhibited cyclooxygenase (COX)-2 expression at both protein and mRNA levels, but to much lesser extents as compared with that for iNOS expression. These data further substantiate the anti-inflammatory potency of DB, AS and CO.