Anti-Inflammatory Effects of New Flavonoids from Streptomyces sp. BT01 in Lipopolysaccharide-Stimulated RAW 264.7 Murine Macrophages via Inhibition of NF-KappaB Activation
Thongchai Taechowisan *
Department of Microbiology, Faculty of Science, Silpakorn University, Nakorn Pathom 73000, Thailand.
Srisakul Chanaphat
Department of Microbiology, Faculty of Science, Silpakorn University, Nakorn Pathom 73000, Thailand.
Wanwikar Ruensamran
Department of Chemistry, Faculty of Science, Silpakorn University, Nakorn Pathom 73000, Thailand.
Waya S. Phutdhawong
Department of Chemistry, Faculty of Science, Silpakorn University, Nakorn Pathom 73000, Thailand.
*Author to whom correspondence should be addressed.
Abstract
Most flavonoids are known to have anti-oxidant, anti-bacterial and analgesic properties. In this study, the new flavonoids, 7-methoxy-3,3’,4’,6-tetrahydroxyflavone (1) and 2’,7-dihydroxy-4’5’-dimethoxyisoflavone (2) isolated from Streptomyces sp. BT01 inhibited the pro-inflammatory mediators including cytokines by blocking nuclear factor-kappaB (NF-κB) signalling in lipopolysaccharide (LPS)-stimulated RAW 264.7 cells. These flavonoids suppressed mRNA and protein expression of inducible nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2) in LPS-stimulated RAW 264.7 cells. The molecular mechanism was associated with the inhibition of NF-κB activation. These results suggest that these flavonoids have anti-inflammatory effects by suppressing expression of iNOS, COX-2 and cytokines by blocking the NF-κB signalling in LPS-stimulated RAW 264.7 cells.
Keywords: Anti-inflammatory effects, flavonoids, RAW 264.7, Streptomyces sp