METHODS: The inhibitory effect of chrysin, kaempferol, morin, silibinin, quercetin, diosmin and hesperidin upon nitric oxide (NO), prostaglandin E(2) (PGE(2)) and tumour necrosis factor-alpha (TNF-alpha) secretion from the LPS-induced RAW 264.7 monocytic macrophage was assessed and IC(50) values obtained. Flavonoids that showed reasonable inhibitory effects in at least two out of the three assays were combined in a series of fixed IC(50) ratios and reassessed for inhibition of NO, PGE(2) and TNF-alpha. Dose-response curves were generated and interactions were analysed using isobolographic analysis.
RESULTS: The experiments showed that only chrysin, kaempferol, morin, and silibinin were potent enough to produce dose-response effects upon at least two out of the three mediators assayed. Combinations of these four flavonoids showed that several combinations afforded highly significant synergistic effects.
CONCLUSIONS: Some flavonoids are synergistic in their anti-inflammatory effects when combined. In particular chrysin and kaempferol significantly synergised in their inhibitory effect upon NO, PGE(2) and TNF-alpha secretion. These findings open further avenues of research into combinatorial therapeutics of inflammatory-related diseases and the pharmacology of flavonoid synergy.
METHODS: The antioxidant and anti-inflammatory activity of DE'RAAQSIN was assessed by measuring the levels of ROS and nitric oxide (NO) produced, using the DCF-DA assay and the Griess reagent assay, respectively. The molecular pathways activated by DE'RAAQSIN were investigated via qPCR.
RESULTS: LPS stimulation of RAW264.7 cells increased the production of nitric oxide (NO) and ROS and resulted in the overexpression of the inducible nitric oxide synthase (iNOS) gene. Furthermore, LPS induced the upregulation of the expression of key proinflammatory genes (IL-6, TNF-α, IL-1β, and CXCL1) and of the antioxidant gene heme oxygenase-1 (HO-1). DE'RAAQSIN demonstrated potent antioxidant and anti-inflammatory activity by significantly reducing the levels of ROS and of secreted NO, simultaneously counteracting the LPS-induced overexpression of iNOS, IL-6, TNF-α, IL-1β, and HO-1. These findings were corroborated by in silico activity prediction and physicochemical analysis of the main agarwood oil components.
CONCLUSIONS: We propose DE'RAAQSIN as a promising alternative managing inflammatory disorders, opening the platform for further studies aimed at understanding the effectiveness of DE'RAAQSIN.
OBJECTIVE: In this study, we aim to investigate the involvement of heme oxygenase-1 (HO-1) in the anti-inflammatory effects of ZnC in lipopolysaccharide (LPS)-induced RAW 264.7 murine macrophages.
MATERIALS AND METHODS: We used immunoblotting analysis to evaluate the involvement of HO-1 in the anti-inflammatory effects of ZnC and the signaling pathway involved was measured using Dual luciferase reporter assay.
RESULTS: Results from immunoblotting analysis demonstrated that pretreatment of cells with ZnC enhanced the expression of HO-1 in RAW 264.7 cells. Pretreatment of cells with HO-1 inhibitor (tin protoporphyrin IX dichloride) significantly attenuated the inhibitory effects of ZnC on nitric oxide (NO) production, inducible nitric oxide synthase (iNOS) expression and NF-κB activation in LPS-induced RAW 264.7 cells, suggesting that HO-1 play an important role in the suppression of inflammatory responses induced by ZnC. Furthermore, results from co-immunoprecipitation of Nrf2 and Keap1 and dual luciferase reporter assay showed that pretreatment of ZnC was able to activate the Nrf2 signaling pathway. Treatment of cells with p38 inhibitor (SB203580), c-Jun N-terminal kinase inhibitor (SP600125), and MEK 1/2 inhibitor (U0126) did not significantly suppress the induction of HO-1 by ZnC. Moreover, our present findings suggest that the effects of ZnC on NO production, HO-1 expression, and Nrf2 activation were attributed to its Zn subcomponent, but not l-carnosine.
CONCLUSION: Pretreatment with ZnC was able to activate Nrf2/HO-1 signaling pathway, thus suppressing the expression of inflammatory mediators, such as NO and iNOS in LPS-induced RAW 264.7 cells.