hnopharmacological relevance: Pluchea indica Less.: (Asteraceae) is a Thai medicinal plant used in
traditional medicine for the treatment of hemorrhoids, lumbago, leucorrhoea and inflammation. This
study investigated the molecular mechanism of anti-inflammatory activity of Pluchea indica leaf extract
in lipopolysaccharide (LPS)-stimulated RAW 264.7 macrophages and also determined its action in acute
inflammation animal models.
Materials and methods: The inhibitory effect of Pluchea indica leaf extract on LPS-induced nitric oxide
(NO) production was evaluated by Griess reaction. Protein and mRNA expressions were determined by
real time RT-PCR and Western blotting analysis, respectively. Inducible nitric oxide synthase (iNOS)
promoter activity was evaluated by iNOS promoter based reporter gene assay. In vivo anti-inflammatory
effect was examined in ethylphenylpropiolate (EPP)-induced ear edema and carrageenan-induced paw
edema in rat models.
Results: Ethyl acetate fraction of ethanol extract of Pluchea indica leaves (EFPI) exhibited the potent
inhibitory effect on NO production in LPS-induced macrophages and also inhibited PGE2 release. EFPI
reduced iNOS mRNA and protein expression through suppressed iNOS promoter activity and nuclear
translocation of subunit p65 of nuclear factor-kB, but did not inhibit phosphorylation of the mitogenactivated
protein kinases (MAPKs). Moreover, EFPI possessed anti-inflammatory activities on acute phase
of inflammation as seen in EPP-induced ear edema and carrageenan-induced paw edema in rats.
Conclusions: These data support the pharmacological basis of Pluchea indica plant as a traditional herbal
medicine for treatment of inflammation