Protective effects of extract of Cleistocalyx operculatus flower buds and its isolated major constituent against LPS-induced endotoxic shock by activating the Nrf2/HO-1 pathway.

The flower buds of Cleistocalyx operculatus are used as an important ingredient in herbal tea and herbal products in several tropical countries. However, their protective effects and underlying mechanisms on lipopolysaccharide (LPS)-induced endotoxic shock remain unclear. The aim of this study was to investigate the anti-inflammatory effects of ethanol extract of C. operculatus flower buds (ECO) and its major constituent 2',4'-dihydroxy-6'-methoxy-3',5'-dimethylchalcone (DMC) in macrophages and in an experimental LPS-induced sepsis mouse model. ECO inhibited the LPS-induced production and expression of pro-inflammatory mediators in macrophages. In an endotoxic shock mouse model, the oral administration of ECO rescued LPS-induced mortality, and attenuated LPS-induced increases in the serum levels of pro-inflammatory mediators, and damage of the lung and liver tissues. ECO increased the nuclear translocation of the nuclear factor erythroid 2-related factor 2 (Nrf2), as well as the expression of Nrf2 target genes, including heme oxygenase-1 (HO-1), in macrophages. Similar to the effects of ECO, DMC also inhibited the LPS-induced inflammatory response in macrophages and endotoxic shock in mice, and activated the Nrf2/HO-1 pathway. In conclusion, our findings suggested that ECO and its major constituent, DMC, attenuated LPS-induced endotoxic shock by activating the Nrf2/HO-1 pathway.

Anti-inflammatory effects of alkaloid enriched extract from roots of Eurycoma longifolia Jack

Objective: To examine the in vitro and in vivo anti-inflammatory effects of the alkaloid enriched extract (ELA) from the roots of Eurycoma longifolia. Methods: The in vitro antiinflammatory effects of ELA were evaluated by examining its inhibitory activities against nitric oxide (NO) production and inducible nitric oxide synthase (iNOS) and cyclooxygenase 2 (COX-2) expressions in lipopolysaccharide (LPS)-stimulated RAW264.7 cells. The level of NO produced in the culture media was determined by Griess method. The iNOS and COX-2 protein expressions were analyzed by Western blot. The in vivo effect of ELA was evaluated on LPS-induced septic shock in mice model. Mice mortality was monitored for 5 days after injection of LPS. The chemical contents of the ELA were determined by using various chromatographic and spectroscopic techniques. Results: The ELA was found to exhibit a significant anti-inflammatory effect in both in vitro and in vivo models. The results demonstrated that ELA dose-dependently inhibited LPS-induced NO production as well as the protein iNOS and COX-2 expressions. In the septic shock model, ELA dose-dependently protected mice from LPS-induced mortality. Further study on the isolated components of ELA indicated that 9,10-dimethoxycanthin-6-one may contribute significantly to the anti-inflammatory effects of the extract. Conclusions: These results suggest that ELA exhibits the anti-inflammatory activity via suppression of pro-inflammatory mediators such as NO, iNOS, and COX-2 and protects mice from LPS-induced mortality in septic shock model.

Lactones from the pericarps of Litsea japonica and their anti-inflammatory activities.

Five new lactones, litsenolide F1 (1), lisealactone H1 (10), lisealactone H2 (11), akolactone D (13), and akolactone E (14), along with thirteen known compounds were isolated from the pericarps of Litsea japonica (Thunb.) Jussieu. Their chemical structures were elucidated by extensive spectroscopic analyses, including 1D and 2D NMR, HRMS, and chemical methods. The isolated compounds were evaluated for their inhibitory effects on NO production in lipopolysaccharide (LPS)-stimulated RAW264.7 cells. Among them, 2-alkylidene-3-hydroxy-4-methylbutanolide derivatives (compounds 1-9) exhibited the most potent activity, with IC50 values in the range of 2.9-12.8 µM. In additon, compounds 1, 3, 4, and 6 showed inhibition of iNOS and COX-2 expression in concentration-dependent manner. Compound 3 suppresses mRNA expression of iNOS, COX-2, IL-6, and TNF-α in LPS-stimulated RAW264.7 cells. Based on these evidence, the isolated lactones from L. japonica could be promissing candidates for the development of new anti-inflammatory agents.

A prenylated flavonoid, 10-oxomornigrol F, exhibits anti-inflammatory effects by activating the Nrf2/heme oxygenase-1 pathway in macrophage cells.

Prenylated flavonoids are a unique class of naturally occurring flavonoids that have various pharmacological activities. In the present study, we investigated the anti-inflammatory effect in murine macrophages of a prenylated flavonoid, 10-oxomornigrol F (OMF), which was isolated from the twigs of Morus alba (Moraceae). OMF inhibited the lipopolysaccharide (LPS)-induced production of nitric oxide (NO), tumor necrosis factor-α (TNF-α), interleukin (IL)-1ß, and IL-6 in RAW264.7 cells, as well as in mouse bone marrow-derived macrophages (BMMs). OMF also rescued LPS-induced septic mortality in ICR mice. LPS-induced expression of inducible nitric oxide synthase (iNOS), cyclooxygenase-2 (COX-2), TNF-α and IL-6 was also significantly suppressed by OMF treatment in RAW264.7 cells. Treatment of RAW264.7 cells with OMF induced heme oxygenase (HO)-1 mRNA and protein expression and increased the nuclear translocation of the nuclear factor-E2-related factor 2 (Nrf2) as well as the expression of Nrf2 target genes, such as NAD(P)H:quinone oxidoreductase 1 (NQO1). Treatment of RAW264.7 cells with OMF increased the intracellular level of reactive oxygen species (ROS) and the phosphorylation levels of p38 mitogen-activated protein kinase (MAPK); co-treatment with the antioxidant N-acetyl-cysteine (NAC) blocked this OMF-induced p38 MAPK phosphorylation. Moreover, NAC, or SB203580 (a p38 MAPK inhibitor), blocked the OMF-induced nuclear translocation of Nrf2 and HO-1 expression, suggesting that OMF induces HO-1 expression by activating Nrf2 through the p38 MAPK pathway. Consistent with the notion that the Nrf2/HO-1 pathway has anti-inflammatory properties, inhibiting HO-1 significantly abrogated the anti-inflammatory effects of OMF in LPS-stimulated RAW264.7 cells. Taken together, these findings suggest that OMF exerts its anti-inflammatory effect by activating the Nrf2/HO-1 pathway, and may be a potential Nrf2 activator to prevent or treat inflammatory diseases.