Ethnopharmacological relevance: The rhizomes of Kaempferia parviflora Wall. ex Baker have been used in Thailand for treatment of gout, apthous ulcer, peptic ulcer and abscesses.
Aim of the study: In our previous study, the crude ethanol extract of Kaempferia parviflora and its compound (5, 5-hydroxy-3,7,3',4'-tetramethoxyflavone), was reported to show nitric oxide (NO) inhibition in RAW 264.7 cells. The present study is thus investigated the anti-inflammatory mechanism of Kaempferia parviflora extract and compound 5 against inducible nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2) mRNA expressions.
Materials and methods: The extract of Kaempferia parviflora and its compound were tested against NO and prostaglandin E(2) (PGE(2)) releases using RAW264.7 cells as well as studied on anti-inflammatory activity in carrageenan-induced rat paw edema and acute toxicity in mice.
Results: The results revealed that the ethanol extract of Kaempferia parviflora markedly inhibited PGE(2) release with an IC(50) value of 9.2 microg/ml. This plant extract and compound 5 also suppressed mRNA expression of iNOS in dose-dependent manners, whereas COX-2 mRNA expression was partly affected. According to the in vivo study, chloroform and hexane fractions greater decreased rat paw edema than ethanol, ethyl acetate and water fractions.
Conclusion: The mechanisms for anti-inflammatory activity of Kaempferia parviflora and compound 5 are mainly due to the inhibition of iNOS mRNA expression but partly through that of COX-2 mRNA.