Fucosterol isolated from Undaria pinnatifida inhibits lipopolysaccharide-induced production of nitric oxide and pro-inflammatory cytokines via the inactivation of nuclear factor-κB and p38 mitogen-activated protein kinase in RAW264.7 macrophages.

It has been reported that fucosterol has anti-diabetic, anti-oxidant, and anti-osteoporotic effects. We investigated the anti-inflammatory effects and the underlying molecular mechanism of fucosterol in lipopolysaccharide (LPS)-induced RAW 264.7 macrophages. Fucosterol suppressed the expressions of inducible nitric oxide synthase (iNOS), tumour necrosis factor-α (TNF-α), and interleukin-6 (IL-6) by downregulating their transcriptions, and subsequently inhibited the productions of nitric oxide, TNF-α, and IL-6. In addition, fucosterol attenuated LPS-induced DNA binding and the transcriptional activity of nuclear factor-κB (NF-κB). These reductions were accompanied by parallel reductions in the phosphorylation and nuclear translocation of NF-κB. Furthermore, fucosterol attenuated the phosphorylations of mitogen-activated protein kinase kinases 3/6 (MKK3/6) and mitogen-activated protein kinase-activated protein kinase 2 (MK2), which are both involved in the p38 MAPK pathway. These results suggest that the anti-inflammatory effects of fucosterol are associated with the suppression of the NF-κB and p38 MAPK pathways.

Anti-inflammatory and anti-arthritic effects of new synthetic 3-(4-hydroxyphenyl)-4-(4-thiomethoxyphenyl)-1H-pyrrole-2,5-dione.

We previously reported that 3-(4-hydroxyphenyl)-4-(4-thiomethoxyphenyl)-1H-pyrrole-2,5-dione (1, HMP) has a strong inhibitory effect on prostaglandin E(2) (PGE(2)) production. In this study, the anti-inflammatory and anti-arthritic effects of HMP were evaluated on LPS-induced RAW 264.7 macrophages and rats with carrageenan-induced paw edema and adjuvant-induced arthritis (AIA). The attenuation of PGE(2) production by HMP was found to be caused by the inhibition of cyclooxygenase-2 (COX-2) activity, but not COX-1 activity. However, HMP did not affect COX-2 at the protein or mRNA levels, whereas it suppressed the releases and expressions of inflammatory cytokines, such as, interleukin-1ß (IL-1ß) and IL-6 in LPS-induced macrophages. Furthermore, HMP suppressed LPS-induced nitric oxide (NO) production by down regulating the protein and mRNA expressions of inducible nitric oxide synthase (iNOS). In rats with carrageenan-injected acute inflammation, oral administration of HMP (25 or 50mg/kg, po) reduced paw swelling, and PGE(2) release and myeloperoxidase (MPO) activity in tissue. Furthermore, HMP (25 or 50mg/kg, po) significantly reduced paw swelling, arthritic indices and plasma PGE(2) concentrations in rat with AIA. These results show that HMP reduces swelling in a model acute inflammation and inhibits arthritic responses in a model of chronic inflammation via the inhibition of PGE(2) production. These results suggest that HMP is a potential therapeutic agent for the treatment of arthritis and associated disorders.

4'-bromo-5,6,7-trimethoxyflavone represses lipopolysaccharide-induced iNOS and COX-2 expressions by suppressing the NF-κB signaling pathway in RAW 264.7 macrophages.

The regulations of the NO and PGE(2) productions are research topics of interest in the field of anti-inflammatory drug development. In the present study, 5,6,7-trimethoxy- and 5,6,7-trihydroxyflavones 3a-3g were synthesized from cinnamic acid derivatives. In particular, 4'-bromo-5,6,7-trimethoxyflavone (3b) most potently inhibited the productions of NO and PGE(2) in LPS-treated RAW 264.7 cells (IC(50)=14.22 ± 1.25 and 10.98 ± 6.25 µM, respectively), and these inhibitory effects were more potent than those of oroxylin A or baicalein. Consistent with these findings, 3b concentration-dependently reduced the LPS-induced expressions of iNOS and COX-2 at the protein and mRNA levels. In addition, the release of TNF-α, IL-6, and IL-1ß and the mRNA expressions of these cytokines were reduced by 3b in a concentration-dependent manner. Furthermore, 3b attenuated the LPS-induced transcriptional activities of NF-κB and this was accompanied by parallel reductions in the degradation and phosphorylation of IκB-α, and consequently by a decrease in the nuclear translocation of the p65 subunit of NF-κB. Taken together, these results suggest that suppressions of the expressions of iNOS, COX-2, TNF-α, IL-6, and IL-1ß via NF-κB inactivation are responsible for the anti-inflammatory effects of 3b.

BRN-103, a novel nicotinamide derivative, inhibits VEGF-induced angiogenesis and proliferation in human umbilical vein endothelial cells.

Anti-angiogenesis is regarded as an effective strategy for cancer treatment, and vascular endothelial growth factor (VEGF) plays a key role in the regulations of angiogenesis and vasculogenesis. In the present study, the authors synthesized five novel nicotinamide derivatives which structurally mimic the receptor tyrosine kinase inhibitor sunitinib and evaluated their anti-angiogenic effects. Transwell migration assays revealed that 2-(1-benzylpiperidin-4-yl) amino-N-(3-chlorophenyl) nicotinamide (BRN-103), among the five derivatives most potently inhibited VEGF-induced human umbilical vein endothelial cells (HUVECs). In addition, BRN-103 dose-dependently inhibited VEGF-induced migration, proliferation, and capillary-like tube formation of HUVECs and vessel sprouting from mouse aortic rings. To understand the molecular mechanisms responsible for these activities, the authors examined the effect of BRN-103 on VEGF signaling pathways in HUVECs. BRN-103 was found to suppress the VEGF-induced phosphorylation of VEGF receptor 2 (VEGR2) and the activations of AKT and eNOS. Taken together, these results suggest that BRN-103 inhibits VEGF-mediated angiogenesis signaling in human endothelial cells.