Activation of Nrf2 by Esculetin Mitigates Inflammatory Responses through Suppression of NF-κB Signaling Cascade in RAW 264.7 Cells.

Inflammation is a major root of several diseases such as allergy, cancer, Alzheimer's, and several others, and the present state of existing drugs provoked researchers to search for new treatment strategies. Plants are regarded to be unique sources of active compounds holding pharmacological properties, and they offer novel designs in the development of therapeutic agents. Therefore, this study aimed to explore the anti-inflammatory mechanism of esculetin in lipoteichoic acid (LTA)-induced macrophage cells (RAW 264.7). The relative expression of inducible nitric oxide synthase (iNOS), nitric oxide (NO) production and COX-2 expression were intensified in LTA-induced RAW cells. The phosphorylation status of mitogen-activated protein kinases (extracellular signal-regulated kinase (ERK)1/2, p38 MAPK, and c-Jun N-terminal kinase (JNK)) and nuclear factor kappa B (NF-κB) p65 were detected by using Western blot assay. The nuclear translocation of p65 was assessed by confocal microscopic image analysis. Esculetin significantly and concentration-dependently inhibited LTA-induced NO production and iNOS expression, but not COX-2 expression, in RAW cells. Esculetin was not effective in LTA-induced MAPK molecules (ERK, p38 and JNK). However, esculetin recovered LTA-induced IκBα degradation and NF-κB p65 phosphorylation. Moreover, esculetin at a higher concentration of 20 µM evidently inhibited the nuclear translocation of NF-κB p65. At the same high concentration, esculetin augmented Nrf2 expression and decreased DPPH radical generation in RAW 264.7 cells. This study exhibits the value of esculetin for the treatment of LTA-induced inflammation by targeting NF-κB signaling pathways via its antioxidant properties.

Decreased Human Platelet Activation and Mouse Pulmonary Thrombosis by Rutaecarpine and Comparison of the Relative Effectiveness with BAY11-7082: Crucial Signals of p38-NF-κB.

Platelets play a critical role in arterial thrombosis. Rutaecarpine (RUT) was purified from Tetradium ruticarpum, a well-known Chinese medicine. This study examined the relative activity of RUT with NF-κB inhibitors in human platelets. BAY11-7082 (an inhibitor of IκB kinase [IKK]), Ro106-9920 (an inhibitor of proteasomes), and RUT concentration-dependently (1-6 µM) inhibited platelet aggregation and P-selectin expression. RUT was found to have a similar effect to that of BAY11-7082; however, it exhibits more effectiveness than Ro106-9920. RUT suppresses the NF-κB pathway as it inhibits IKK, IκBα, and p65 phosphorylation and reverses IκBα degradation in activated platelets. This study also investigated the role of p38 and NF-κB in cell signaling events and found that SB203580 (an inhibitor of p38) markedly reduced p38, IKK, and p65 phosphorylation and reversed IκBα degradation as well as p65 activation in a confocal microscope, whereas BAY11-7082 had no effects in p38 phosphorylation. The 2,2-diphenyl-1-picrylhydrazyl (DPPH) assay shows that RUT and BAY11-7082 did not exhibit free radical scavenging activity. In the in vivo study, compared with BAY11-7082, RUT more effectively reduced mortality in adenosine diphosphate (ADP)-induced acute pulmonary thromboembolism without affecting the bleeding time. In conclusion, a distinctive pathway of p38-mediated NF-κB activation may involve RUT-mediated antiplatelet activation, and RUT could act as a strong prophylactic or therapeutic drug for cardiovascular diseases.

Rutaecarpine, an Alkaloid from Evodia rutaecarpa, Can Prevent Platelet Activation in Humans and Reduce Microvascular Thrombosis in Mice: Crucial Role of the PI3K/Akt/GSK3ß Signal Axis through a Cyclic Nucleotides/VASP-Independent Mechanism.

The role of activated platelets in acute and chronic cardiovascular diseases (CVDs) is well established. Therefore, antiplatelet drugs significantly reduce the risk of severe CVDs. Evodia rutaecarpa (Wu-Chu-Yu) is a well-known Chinese medicine, and rutaecarpine (Rut) is a main bioactive component with substantial beneficial properties including vasodilation. To address a research gap, we investigated the inhibitory mechanisms of Rut in washed human platelets and experimental mice. At low concentrations (1-5 µM), Rut strongly inhibited collagen-induced platelet aggregation, whereas it exerted only a slight or no effect on platelets stimulated with other agonists (e.g., thrombin). Rut markedly inhibited P-selectin expression; adenosine triphosphate release; [Ca2+]i mobilization; hydroxyl radical formation; and phospholipase C (PLC)γ2/protein kinase C (PKC), mitogen-activated protein kinase, and phosphoinositide 3-kinase (PI3K)/Akt/glycogen synthase kinase-3ß (GSK3ß) phosphorylation stimulated by collagen. SQ22536 (an adenylate cyclase inhibitor) or ODQ (a guanylate cyclase inhibitor) did not reverse Rut-mediated antiplatelet aggregation. Rut was not directly responding to vasodilator-stimulated phosphoprotein phosphorylation. Rut significantly increased the occlusion time of fluorescence irradiated thrombotic platelet plug formation. The findings demonstrated that Rut exerts a strong effect against platelet activation through the PLCγ2/PKC and PI3K/Akt/GSK3ß pathways. Thus, Rut can be a potential therapeutic agent for thromboembolic disorders.

The Antithrombotic Agent Pterostilbene Interferes with Integrin αIIbß3-Mediated Inside-Out and Outside-In Signals in Human Platelets.

Platelets play a crucial role in the physiology of primary hemostasis and pathological processes such as arterial thrombosis; thus, developing a therapeutic target that prevents platelet activation can reduce arterial thrombosis. Pterostilbene (PTE) has remarkable pharmacological activities, including anticancer and neuroprotection. Few studies have reported the effects of pterostilbene on platelet activation. Thus, we examined the inhibitory mechanisms of pterostilbene in human platelets and its role in vascular thrombosis prevention in mice. At low concentrations (2-8 µM), pterostilbene strongly inhibited collagen-induced platelet aggregation. Furthermore, pterostilbene markedly diminished Lyn, Fyn, and Syk phosphorylation and hydroxyl radical formation stimulated by collagen. Moreover, PTE directly hindered integrin αIIbß3 activation through interfering with PAC-1 binding stimulated by collagen. In addition, pterostilbene affected integrin αIIbß3-mediated outside-in signaling, such as integrin ß3, Src, and FAK phosphorylation, and reduced the number of adherent platelets and the single platelet spreading area on immobilized fibrinogen as well as thrombin-stimulated fibrin clot retraction. Furthermore, pterostilbene substantially prolonged the occlusion time of thrombotic platelet plug formation in mice. This study demonstrated that pterostilbene exhibits a strong activity against platelet activation through the inhibition of integrin αIIbß3-mediated inside-out and outside-in signaling, suggesting that pterostilbene can serve as a therapeutic agent for thromboembolic disorders.

Dietary Supplementation of Magnesium Oxide (MgO) Nanoparticles for Better Survival and Growth of the Freshwater Prawn Macrobrachium rosenbergii Post-larvae.

This study was performed to assess the growth-promoting potential of dietary magnesium oxide nanoparticles (MgO NPs) in Macrobrachium rosenbergii post-larvae (PL). MgO NPs were supplemented at 0, 100, 200, 300, 400 and 500 mg kg-1 with the basal diet (containing 0.95 g Mg kg-1); the concentrations of Mg in MgO NP-supplemented diets were increased correspondingly (1.07, 1.15, 1.24, 1.37 and 1.46 g Mg kg-1 respectively). MgO NP-supplemented diets were fed to M. rosenbergii PL (initial weight 0.11 ± 0.04 g) for a period of 90 days. In the carcasses of experimental prawns, the content of Mg was found to be elevated significantly with respect to the individual diet (102.14, 183.29, 205.46, 221.03, 237.10 and 254.36 µg Mg g-1 respectively) when compared with that of the control. The contents of Cu, Zn, Fe, Ca, Na and K levels were also found to be elevated in the carcasses of experimental prawns. Significant (P < 0.05) improvements were observed in nutritional indices [survival rate (SR), weight gain (WG), specific growth rate (SGR), feed conversion ratio (FCR) and protein efficiency ratio (PER)], activities of digestive enzymes (protease, amylase and lipase), concentrations of basic biochemical constituents (total protein, amino acid, carbohydrate, lipid, profiles of amino acids and fatty acids) and population of haemocytes [total and differential (hyalinocytes, semigranulocytes and granulocytes)] in all the test PL. Maximum performance was recorded in 500 mg kg-1 MgO NP-supplemented-feed-fed PL. There were no significant elevations recorded in activities of antioxidant enzymes [superoxide dismutase (SOD) and catalase (CAT)], lipid peroxidation (LPO) and metabolic enzymes [glutamic oxaloacetic transaminase (GOT) and glutamic pyruvic transaminase (GPT)] recorded in any of the MgO NP-supplemented-feed-fed PL when compared with the control. Sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) showed increases in the staining intensity of polypeptide bands resolved in 500 mg kg-1 MgO NP-supplemented-feed-fed PL when compared with the control. Based on the gradual improvement in attaining survival, growth, FCR, biochemical constituents and haemocyte population, this study recommends MgO NP supplementation of 500 mg kg-1 for sustainable maintenance of M. rosenbergii PL. As the studied highest concentration of MgO NPs showed the best performance, it is necessary to study with beyond 500 mg kg-1 of MgO NPs to optimize the actual concentration.