Effects of compounds from Kaempferia parviflora on nitric oxide, prostaglandin E2 and tumor necrosis factor-alpha productions in RAW264.7 macrophage cells

Kaempferia parviflora Wall. ex Baker, is one of the plants in the Zingiberaceae family, locally known in Thai as kra-chai-dam. The rhizome of this plant has been used for treatment of gout, apthous ulcer and abscesses. Since K. parviflora rhizomes have long been used for treatment of inflammation and possessed marked nitric oxide (NO) inhibitory activity (IC50 = 7.8 μg/ml), we thus investigated the inhibitory activity of compounds isolated from this plant against lipopolysaccharide (LPS)-induced NO release in RAW264.7 cells.From bioassay-guided fractionation of K. parviflora, seven methoxyflavones were isolated from the hexane fraction and were tested for their anti-inflammatory effects. Among the isolated compounds, compound 5 (5-hydroxy-3,7,3′,4′-tetramethoxyflavone) exhibited the highest activity against NO release with an IC50 value of 16.1 μM, followed by 4 (IC50 = 24.5 μM) and 3 (IC50 = 30.6 μM). Compound 5 was also tested on LPS-induced prostaglandin E2 (PGE2) and tumor necrosis factor-alpha (TNF-α) releases from RAW264.7 cells. It was revealed that 5 showed appreciable inhibitory effect on PGE2 release (IC50 = 16.3 μM), but inactive on TNF-α (IC50 > 100 μM). These findings may support the use in Thai traditional medicine of K. parviflora for treatment of inflammatory-related diseases through the inhibition of NO and PGE2 releases but partly due to that of TNF-α.