Effects of 3-(2-Hydroxyphenyl)-1-(5-methyl-furan-2-y-l) propenone (HMP) upon signalling pathways of lipopolysaccharide-induced iNOS synthesis in RAW 264.7 cells

Euryfuranyl compounds from edible species of cuttlefish as potential anti-inflammatory leads attenuating NF-κB signaling cascade in lipopolysaccharide-activated macrophages

Nuclear factor-kappa B is an inducible transcription element, which was considered as an important regulator of immune functions, and plays a critical role to induce inflammatory reactions. In this study, we have demonstrated the anti-inflammatory potentials of previously undescribed (4 → 13)-abeo-euryfuranyls (1-2) from the spineless cuttlefish Sepiella inermis in lipopolysaccharide-stimulated macrophages. The euryfuranyl bearing (4 → 13)-abeo-euryfuranyl-2-ene-6-hydroxymethyl-propanoate framework (compound 1) displayed prominent inhibitory effects against pro-inflammatory cyclooxygenase-2 (IC₅₀ 0.36 mM) and 5-lipoxygenase (IC₅₀ 0.70 mM). Additionally, it suppressed the generation of inducible nitric oxide synthase along with cyclooxygenase-2 and 5-lipoxygenase in lipopolysaccharide-stimulated macrophages. The euryfuranyl analogue (1) down-regulated the mRNA expression of cyclooxygenase-2 and nuclear factor-κB signaling pathway in lipopolysaccharide-activated macrophage cells by hindering the degradation of inhibitor-κB proteins, and transfer of the subunit NF-κB p⁶⁵ to the nucleus from the cytosol. These results demonstrated that the euryfuranyl analogue could be explored as a promising anti-inflammatory therapeutic lead attenuating nuclear factor-κB signaling cascade.

(E)-1-(Furan-2-yl)-(substituted phenyl)prop-2-en-1-one Derivatives as Tyrosinase Inhibitors and Melanogenesis Inhibition: An In Vitro and In Silico Study

A series of (E)-1-(furan-2-yl)prop-2-en-1-one derivatives (compounds 1–8) were synthesized and evaluated for their mushroom tyrosinase inhibitory activity. Among these series, compound 8 (2,4-dihydroxy group bearing benzylidene) showed potent tyrosinase inhibitory activity, with respective IC₅₀ values of 0.0433 µM and 0.28 µM for the monophenolase and diphenolase as substrates in comparison to kojic acid as standard compound 19.97 µM and 33.47 µM. Moreover, the enzyme kinetics of compound 8 were determined to be of the mixed inhibition type and inhibition constant (K_i) values of 0.012 µM and 0.165 µM using the Lineweaver-Burk plot. Molecular docking results indicated that compound 8 can bind to the catalytic and allosteric sites 1 and 2 of tyrosinase to inhibit enzyme activity. The computational molecular dynamics analysis further revealed that compound 8 interacted with two residues in the tyrosinase active site pocket, such as ASN260 and MET280. In addition, compound 8 attenuated melanin synthesis and cellular tyrosinase activity, simulated by α-melanocyte-stimulating hormone and 1-methyl-3-isobutylxanthine. Compound 8 also decreased tyrosinase expressions in B16F10 cells. Based on in vitro and computational studies, we propose that compound 8 might be a worthy candidate for the development of an antipigmentation agent.

Anti-Inflammatory Effects of Formononetin 7-O-phosphate, a Novel Biorenovation Product, on LPS-Stimulated RAW 264.7 Macrophage Cells

Biorenovation is a microbial enzyme-catalyzed structural modification of organic compounds with the potential benefits of reduced toxicity and improved biological properties relative to their precursor compounds. In this study, we synthesized a novel compound verified as formononetin 7-O-phosphate (FMP) from formononetin (FM) using microbial biotransformation. We further compared the anti-inflammatory properties of FMP to FM in lipopolysaccharide (LPS)-treated RAW264.7 macrophage cells. We observed that cell viabilities and inhibitory effects on LPS-induced nitric oxide (NO) production were greater in FMP-treated RAW 264.7 cells than in their FM-treated counterparts. In addition, FMP treatment suppressed the production of proinflammatory cytokines such as prostaglandin-E₂ (PGE₂), interleukin-6 (IL-6), and interleukin-1β (IL-1β) in a dose-dependent manner and concomitantly decreased the mRNA expression of inducible NO synthase (iNOS) and cyclooxygenase-2 (COX-2). We also found that FMP exerted its anti-inflammatory effects through the downregulation of the extracellular signal-regulated kinase (ERK), c-Jun N-terminal kinase (JNK), and nuclear factor kappa B (NF-κB) signaling pathways. In conclusion, we generated a novel anti-inflammatory compound using biorenovation and demonstrated its efficacy in cell-based in vitro assays.

Anti-inflammatory effect of trans-4-methoxycinnamaldehyde from Etlingera pavieana in LPS-stimulated macrophages mediated through inactivation of NF-κB and JNK/c-Jun signaling pathways and in rat models of acute inflammation

Trans-4-methoxycinnamaldehyde (MCD) was isolated from the rhizomes of Etlingera pavieana (Pierre ex Gagnep.) R.M.Sm. MCD shows anti-inflammatory effects. However, the molecular mechanism underlying its anti-inflammatory action has not been described. In this study, we investigated this mechanism in lipopolysaccharide (LPS)-induced RAW 264.7 macrophages and found MCD significantly inhibited nitric oxide (NO) and prostaglandin E₂ (PGE₂) production in a concentration-dependent manner. MCD could decrease LPS- and Pam3CSK4- induced the expressions of both iNOS and COX-2. The phosphorylation of inhibitory κB (IκB) and translocation of nuclear factor-κB (NF-κB) p65 subunit into the nucleus were also inhibited by MCD. Moreover, MCD suppressed LPS-induced phosphorylation of JNK except for ERK and p38 mitogen-activated protein kinases (MAPKs). Moreover, MCD significantly reduced ethyl phenylpropiolate-induced ear edema and carrageenan-induced paw edema in rat models. These findings indicated MCD has anti-inflammatory activity by inhibiting the production of NO and PGE₂ by blocking NF-κB and JNK/c-Jun signaling pathways. Collectively, these data suggest that MCD could be developed as a novel therapeutic agent for inflammatory disorders.

18α-Glycyrrhetinic acid monoglucuronide as an anti-inflammatory agent through suppression of the NF-κB and MAPK signaling pathway

Based on the SAR analysis of glycyrrhizin, 18α-glycyrrhetinic acid monoglucuronide (18α-GAMG) with strong inhibition against LPS-induced NO and IL-6 production in RAW264.7 cells was discovered. Western blotting and immunofluorescence results showed that 18α-GAMG reduced the expression of iNOS, COX-2, and MAPKs, as well as activation of NF-κB in the LPS-stimulated RAW264.7 cells. Further in vivo results showed that 18α-GAMG could significantly improve the pathological changes of CCl4-induced hepatic fibrosis.

Immunosuppressive Effects of Natural α,β-Unsaturated Carbonyl-Based Compounds, and Their Analogs and Derivatives, on Immune Cells: A Review

The immune system is complex and pervasive as it functions to prevent or limit infections in the human body. In a healthy organism, the immune system and the redox balance of immune cells maintain homeostasis within the body. The failure to maintain the balance may lead to impaired immune response and either over activity or abnormally low activity of the immune cells resulting in autoimmune or immune deficiency diseases. Compounds containing α,β-unsaturated carbonyl-based moieties are often reactive. The reactivity of these groups is responsible for their diverse pharmacological activities, and the most important and widely studied include the natural compounds curcumin, chalcone, and zerumbone. Numerous studies have revealed the mainly immunosuppressive and anti-inflammatory activities of the aforesaid compounds. This review highlights the specific immunosuppressive effects of these natural α,β-unsaturated carbonyl-based compounds, and their analogs and derivatives on different types of immune cells of the innate (granulocytes, monocytes, macrophages, and dendritic cells) and adaptive (T cells, B cells, and natural killer cells) immune systems. The inhibitory effects of these compounds have been comprehensively studied on neutrophils, monocytes and macrophages but their effects on T cells, B cells, natural killer cells, and dendritic cells have not been well investigated. It is of paramount importance to continue generating experimental data on the mechanisms of action of α,β-unsaturated carbonyl-based compounds on immune cells to provide useful information for ensuing research to discover new immunomodulating agents.

Effects of chalcone derivatives on players of the immune system

The immune system is the defense mechanism in living organisms that protects against the invasion of foreign materials, microorganisms, and pathogens. It involves multiple organs and tissues in human body, such as lymph nodes, spleen, and mucosa-associated lymphoid tissues. However, the execution of immune activities depends on a number of specific cell types, such as B cells, T cells, macrophages, and granulocytes, which provide various immune responses against pathogens. In addition to normal physiological functions, abnormal proliferation, migration, and differentiation of these cells (in response to various chemical stimuli produced by invading pathogens) have been associated with several pathological disorders. The unwanted conditions related to these cells have made them prominent targets in the development of new therapeutic interventions against various pathological implications, such as atherosclerosis and autoimmune diseases. Chalcone derivatives exhibit a broad spectrum of pharmacological activities, such as immunomodulation, as well as anti-inflammatory, anticancer, antiviral, and antimicrobial properties. Many studies have been conducted to determine their inhibitory or stimulatory activities in immune cells, and the findings are of significance to provide a new direction for subsequent research. This review highlights the effects of chalcone derivatives in different types of immune cells.

The anti-inflammatory activity of a novel fused-cyclopentenone phosphonate and its potential in the local treatment of experimental colitis

A novel fused-cyclopentenone phosphonate compound, namely, diethyl 3-nonyl-5-oxo-3,5,6,6a-tetrahydro-1H-cyclopenta[c]furan-4-ylphosphonate (P-5), was prepared and tested in vitro (LPS-activated macrophages) for its cytotoxicity and anti-inflammatory activity and in vivo (DNBS induced rat model) for its potential to ameliorate induced colitis. Specifically, the competence of P-5 to reduce TNFα, IL-6, INFγ, MCP-1, IL-1α, MIP-1α, and RANTES in LPS-activated macrophages was measured. Experimental colitis was quantified in the rat model, macroscopically and by measuring the activity of tissue MPO and iNOS and levels of TNFα and IL-1β. It was found that P-5 decreased the levels of TNFα and the tested proinflammatory cytokines and chemokines in LPS-activated macrophages. In the colitis-induced rat model, P-5 was effective locally in reducing mucosal inflammation. This activity was equal to the activity of local treatment with 5-aminosalicylic acid. It is speculated that P-5 may be used for the local treatment of IBD (e.g., with the aid of colon-specific drug platforms). Its mode of action involves inhibition of the phosphorylation of MAPK ERK but not of p38 and had no effect on IκBα.