Isorhamnetin as a novel inhibitor of pneumolysin against Streptococcus pneumoniae infection in vivo/in vitro.

The increasing incidence of Streptococcus pneumoniae (S. pneumoniae) infection severely threatened the global public heath, causing a significant fatality in immunocompromised hosts. Notably, pneumolysin (PLY) as a pore-forming cytolysin plays a crucial role in the pathogenesis of pneumococcal pneumonia and lung injury. In this study, a natural flavonoid isorhamnetin was identified as a PLY inhibition to suppress PLY-induced hemolysis by engaging the predicted residues and attenuate cytolysin PLY-mediated A549 cells injury. Underlying mechanisms revealed that PLY inhibitor isorhamnetin further contributed to decrease the formation of bacterial biofilms without affecting the expression of PLY. In vivo S. pneumoniae infection confirmed that the pathological injury of lung tissue evoked by S. pneumoniae was ameliorated by isorhamnetin treatment. Collectively, these results presented that isorhamnetin could inhibit the biological activity of PLY, thus reducing the pathogenicity of S. pneumoniae. In summary, our study laid a foundation for the feasible anti-virulence strategy targeting PLY, and provided a promising PLY inhibitor for the treatment of S. pneumoniae infection.

Therapeutic potential of kaempferol on Streptococcus pneumoniae infection.

Co-infections with pathogens and secondary bacterial infections play significant roles during the pandemic coronavirus disease 2019 (COVID-19) pathogenetic process, caused by Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2). Notably, co-infections with Streptococcus pneumoniae (S. pneumoniae), as a major Gram-positive pathogen causing pneumonia or meningitis, severely threaten the diagnosis, therapy, and prognosis of COVID-19 worldwide. Accumulating evidences have emerged indicating that S. pneumoniae evolves multiple virulence factors, including pneumolysin (PLY) and sortase A (SrtA), which have been extensively explored as alternative anti-infection targets. In our study, natural flavonoid kaempferol was identified as a potential candidate drug for infection therapeutics via anti-virulence mechanisms. We found that kaempferol could interfere with the pore-forming activity of PLY by engaging with catalytic active sites and consequently inhibit PLY-mediated cytotoxicity. Additionally, exposed to kaempferol significantly reduced the SrtA peptidase activity by occupying the active sites of SrtA. Further, the biofilms formation and bacterial adhesion to the host cells could be significantly thwarted by kaempferol incubation. In vivo infection model by S. pneumoniae highlighted that kaempferol oral administration exhibited notable treatment benefits, as evidenced by decreased bacterial burden, suggesting that kaempferol has tremendous potential to attenuate S. pneumoniae pathogenicity. Scientifically, our study implies that kaempferol is a promising therapeutic option by targeting bacterial virulence factors.

Shionone-Targeted Pneumolysin to Ameliorate Acute Lung Injury Induced by Streptococcus pneumoniae In Vivo and In Vitro.

Streptococcus pneumoniae (S. pneumoniae), as a Gram-positive bacterium, can cause severe bacterial pneumonia, and result in high morbidity and mortality in infected people. Meanwhile, isolated drug-resistant S. pneumoniae is growing, which raises concerns about strategies for combatting S. pneumoniae infection. To disturb S. pneumoniae pathogenicity and its drug-resistance, developing novel anti-infective strategies or compounds is urgent. In this study, the anti-infective effect of shionone was explored. A minimum inhibitory concentration (MIC) assay and growth curve determination were performed to evaluate the effect of the tetracyclic triterpenoid compound shionone against S. pneumoniae. Hemolysis tests, western blotting, oligomerization inhibition assays, and molecular docking were carried out to explore the anti-infective mechanism of shionone. Moreover, the protective effect of shionone was also confirmed in a mousepneumonia model. The results showed that the excellent hemolytic inhibitory activity of shionone was observed at less than 8 µg/mL. Meanwhile, shionone could disturb the oligomerization of pneumolysin (PLY) but did not interfere with PLY expression at less than 4 µg/mL. Molecular docking suggested that shionone targeted the ASP-59, ILE-60, THR-57, PHE-344, and ASN-346 amino acid sites to reduce S. pneumoniae pathogenicity. Furthermore, shionone alleviated lung histopathologic injury and decreased lung bacterial colonization in vivo. The above results showed that shionone could bind to the PLY active pocket under the concentrations of 8 µg/mL and neutralize PLY hemolysis activity to reduce S. pneumoniae pathogenicity in vitro and in vivo.

Alnustone inhibits Streptococcus pneumoniae virulence by targeting pneumolysin and sortase A.

Streptococcus pneumoniae (S. pneumoniae) is a major Gram-positive opportunistic pathogen that causes pneumonia, bacteremia, and other fatal infections. This bacterium is responsible for more deaths than any other single pathogen in the world. Inexplicably, these symptoms persist despite the administration of effective antibiotics. Targeting pneumolysin (PLY) and sortase A (SrtA), the major virulence factors of S. pneumoniae, this study uncovered a novel resistance mechanism to S. pneumoniae infection. Using protein phenotype assays, we determined that the small molecule inhibitor alnustone is a potent drug that inhibits both PLY and SrtA. As essential virulence factors of S. pneumoniae, PLY and SrtA play a significant role in the occurrence of infection. Furthermore, evaluation using PLY-mediated hemolysis assay demonstrated alunstone had the potential to interrupt the haemolytic activity of PLY with treatment alunstone (4 µg/ml). Co-incubation of S. pneumoniae D39 SrtA with small-molecule inhibitors decreases cell wall-bound Nan A (pneumococcal-anchored surface protein SrtA), inhibits biofilm formation, and reduces biomass significantly. The protective effect of invasive pneumococcal disease (IPD) on murine S. pneumoniae was demonstrated further. Our study proposes a comprehensive bacteriostatic mechanism for S. pneumoniae and highlights the significant translational potential of targeting both PLY and SrtA to prevent pneumococcal infections. Our findings indicate that the antibacterial strategy of directly targeting PLY and SrtA with alnustone is a promising treatment option for S. pneumoniae and that alnustone is a potent inhibitor of PLY and SrtA.

Corilagin: A Novel Antivirulence Strategy to Alleviate Streptococcus pneumoniae Infection by Diminishing Pneumolysin Oligomers.

Pneumolysin (PLY) is a significant virulence factor of Streptococcus pneumoniae (S. pneumoniae), able to break through the defense system of a host and mediate the occurrence of a series of infections. Therefore, PLY as the most ideal target to prevent S. pneumoniae infection has received more and more attention and research. Corilagin is a tannic acid that exhibits excellent inhibition of PLY oligomers without bacteriostatic activity to S. pneumoniae. Herein, hemolytic activity assays, cell viability tests and western blot experiments are executed to evaluate the antivirulence efficacy of corilagin against PLY in vitro. Colony observation, hematoxylin and eosin (H&E) staining and cytokines of bronchoalveolar lavage fluid (BALF) are applied to assess the therapeutic effect of corilagin in mice infected by S. pneumoniae. The results indicate the related genes of corilagin act mainly via enrichment in pathways associated with pneumonia disease. Furthermore, molecular docking and molecular dynamics simulations show that corilagin might bind with domains 3 and 4 of PLY and interfere with its hemolytic activity, which is further confirmed by the site-directed mutagenesis of PLY. Additionally, corilagin limits PLY oligomer production without impacting PLY expression in S. pneumoniae cultures. Moreover, corilagin effectively relieves PLY-mediated cell injury without any cytotoxicity, even then reducing the colony count in the lung and the levels of pro-inflammatory factors in BALF and remarkably improving lung lesions. All the results demonstrate that corilagin may be a novel strategy to cope with S. pneumoniae infection by inhibiting PLY oligomerization.

Quercetin, a pneumolysin inhibitor, protects mice against Streptococcus pneumoniae infection.

Pneumolysin (PLY), a pore-forming cytotoxin and a major virulence determinant, is a member of the cholesterol-dependent cytolysin (CDC) family and essential for promoting Streptococcus pneumoniae (S.pneumoniae) infection. Due to the action characteristics of hemolysin itself, the pneumolysin released after killing bacteria with conventional antibiotics still has the ability to damage host cells; therefore, drug treatments directly inhibiting hemolysin activity are the most effective. Hemolysis assays were used to confirm that quercetin can inhibit the activity of PLY, protecting cells in vitro, and an oligomerization assay was used to determine the mechanism of quercetin to suppress PLY activity. Live/Dead testing, lactate dehydrogenase (LDH) release analysis and a murine model of endonasal pulmonary infection were used to explore the capability of quercetin to protect cells and mice from S. pneumoniae-mediated damage in vivo and in vitro. The results indicated that quercetin significantly reduced PLY-induced hemolytic activity and cytotoxicity via repressing the formation of oligomers. In addition, treatment with quercetin can reduce PLY-mediated cell injury, improve the survival rate of mice infected with a lethal dose of S. pneumoniae, alleviate the pathological damage of lung tissue and inhibit the release of cytokines (IL-1ß and TNF-α) in bronchoalveolar lavage fluid. Considering the importance of these events in antimicrobial resistant S. pneumoniae pathogenesis, our results indicated that quercetin may be a novel potential drug candidate for the treatment of clinical pneumococcal infections.

Morin reduces inflammatory responses and alleviates lipid accumulation in hepatocytes.

Morin (MO), a natural bioflavinoid, exists in many herbs. Previous studies have acclaimed MO's anti-inflammatory, antidiabetic, antioxidant, antifibrotic, anticancer, and antihyperglycemic biological effects. This study aimed to assess the molecular mechanism of MO involved in the oleic acid (OA)-induced inflammatory damage and lipid accumulation in HepG2 cell and tyloxapol (Ty)-induced hyperlipidemia in mice. We found that MO can efficaciously mitigate reactive tumor necrosis factor-α (TNF-α) level and triglyceride (TG) accumulation in OA-induced HepG2 cell and in tyloxapol-induced mice. Next, the study testified that MO apparently suppressed OA-excited nuclear factor-kappa B (NF-κB) and mitogen-activated protein kinases (MAPKs) signaling pathways in HepG2 cell. In addition, MO distinctly upregulated the expression of peroxisome proliferator-activated receptor α (PPARα) and decreased the expression of sterol regulatory element-binding protein 1c (SREBP-1c) in OA-induced HepG2 cell and in tyloxapol-induced mice, both of which are dependent upon the phosphorylation of acetyl-CoA carboxylase (ACC), adenosine 5'-monophosphate (AMP)-activated protein kinase (AMPK), and protein kinase B (AKT). In conclusion, these results suggest that MO has protective potential against hyperlipidemia and steatosis, and the potential mechanism may have a close relation with activation of PPARα and inhibition of SREBP-1c.

Isorhamnetin ameliorates LPS-induced inflammatory response through downregulation of NF-κB signaling.

Isorhamnetin, a flavonoid mainly found in Hippophae fhamnoides L. fruit, has been known for its antioxidant activity and its ability to regulate immune response. In this study, we investigated whether isorhamnetin exerts potent antiinflammatory effects in RAW264.7 cell and mouse model stimulated by LPS. The cytokine (TNF-α, IL-1ß, and IL-6) levels were determined. In the mouse model of acute lung injury, the phosphorylation of NF-κB proteins was analyzed and inhibitor of NF-κB signaling (PDTC) was used on mice. Our results showed that isorhamnetin markedly decreased TNF-α, IL-1ß, and IL-6 concentrations and suppressed the activation of NF-κB signaling. Meanwhile, isorhamnetin reduced the amount of inflammatory cells, the lung wet-to-dry weight ratio, protein leakage, and myeloperoxidase activity. Interference with specific inhibitor revealed that isorhamnetin-mediated suppression of cytokines and protein was via NF-κB signaling. So, it suggests that isorhamnetin might be a potential therapeutic agent for preventing inflammatory diseases.

Isorhamnetin protects mice from lipopolysaccharide-induced acute lung injury via the inhibition of inflammatory responses.

OBJECTIVE AND DESIGN: Isorhamnetin (Isor), a 3-O-methylated metabolite of quercetin, has shown antioxidant and anti-proliferative effects in previous studies. In this study, we investigated the anti-inflammatory effect of Isor on LPS-induced acute lung injury (ALI). Accordingly, we evaluated the effect of Isor on cytokine production elevated by LPS (1 µg/ml) in vitro. An in vivo ALI murine model was also established via lipopolysaccharide inhalation (LPS, 20 mg/kg), and the cytokine levels and inflammatory cell count in bronchoalveolar lavage fluid (BALF) were evaluated. The observed lung injury was assessed using histopathologic sections via H&E straining. Furthermore, to investigate whether the anti-inflammatory effect of Isor is associated with NF-κB and MAPKs pathway activation, the phosphorylated levels of ERK, JNK, IκBa and NF-κB(p65) were determined. RESULTS: Isor significantly inhibited LPS-induced TNF-α, IL-1ß and IL-6 secretion both in vitro and in vivo. Neutrophil infiltration and edema in an ALI model were substantially alleviated. The histopathological changes induced by LPS were lessened by Isor. Additionally, Isor notably suppressed the phosphorylation of ERK, JNK, IκBa and NF-κB(p65) activated by LPS in vivo. CONCLUSIONS: Isor showed efficient protective effects on an LPS-induced ALI model. MAPKs and NF-κB pathways are critical for Isor to perform its protective effects.

Pretreatment with the compound asperuloside decreases acute lung injury via inhibiting MAPK and NF-κB signaling in a murine model.

Asperuloside, an iridoid glycoside found in Herba Paederiae, is a component from traditional Chinese herbal medicine. In this study, we aimed to investigate the protective effects and potential mechanisms of asperuloside action on inflammatory responses in lipopolysaccharide (LPS)-stimulated Raw 264.7 cells and an LPS-induced lung injury model. The pro-inflammatory cytokines and signaling pathways were measured by enzyme-linked immunosorbent assays (ELISA) and Western blotting to determine the effects of asperuloside. We found that asperuloside can significantly downregulate tumor necrosis factor alpha (TNF-α), interleukin (IL)-1ß, and IL-6 levels in vitro and in vivo, and treatment with asperuloside significantly reduced the lung wet-to-dry weight, histological alterations and myeloperoxidase activity in a murine model of LPS-induced acute lung injury (ALI). In addition, Western blot analysis that pretreatment with asperuloside remarkably blunted the phosphorylation of inhibitor of nuclear factor kappa-B (IκBα), extracellular signal-related kinases 1 and 2 (ERK1/2), c-Jun. N-terminal kinase (JNK) and p38 mitogen-activated protein kinase (p38MAPK) in LPS-stimulated inflammation. These results indicate that asperuloside exerts its anti-inflammatory effect in correlation with inhibition of a pro-inflammatory mediator through suppressing nuclear factor kappa-B (NF-κB) nuclear translocation and MAPK phosphorylation in a dose-dependent manner.

D(-)-Salicin inhibits the LPS-induced inflammation in RAW264.7 cells and mouse models.

D(-)-Salicin is a traditional medicine which has been known to exhibit anti-inflammation and other therapeutic activities. The present study aimed to investigate whether D(-)-Salicin inhibited the LPS-induced inflammation in vivo and in vitro. We evaluated the effect of D(-)-Salicin on cytokines (TNF-α, IL-1ß, IL-6 and IL-10) in vivo and in vitro by enzyme-linked immunosorbent assay and signaling pathways (MAPKs and NF-κB) in vivo by Western blot. The results showed that D(-)-Salicin markedly decreased TNF-α, IL-1ß and IL-6 concentrations and increased IL-10 concentration. In addition, western blot analysis indicated that D(-)-Salicin suppressed the activation of MAPKs and NF-κB signaling pathways stimulated by LPS. To examine whether D(-)-Salicin ameliorated LPS-induced lung inflammation, inhibitors of MAPKs and NF-κB signaling pathways were administrated intraperitoneally to mice. Interference with specific inhibitors revealed that D(-)-Salicin-mediated cytokine suppression was through MAPKs and NF-κB pathways. In the mouse model of acute lung injury, histopathologic examination indicted that D(-)-Salicin suppressed edema induced by LPS. So it is suggest that D(-)-Salicin might be a potential therapeutic agent against inflammatory diseases.

Prime-O-glucosylcimifugin attenuates lipopolysaccharide-induced acute lung injury in mice.

Prime-O-glucosylcimifugin is an active chromone isolated from Saposhnikovia root which has been reported to have various activities, such as anti-convulsant, anticancer, anti-inflammatory properties. The purpose of this study was to evaluate the effect of prime-O-glucosylcimifugin on acute lung injury (ALI) induced by lipopolysaccharide in mice. BALB/c mice received intraperitoneal injection of Prime-O-glucosylcimifugin 1h before intranasal instillation (i.n.) of lipopolysaccharide (LPS). Concentrations of tumor necrosis factor (TNF)-α, interleukin (IL)-1ß and interleukin (IL)-6 in bronchoalveolar lavage fluid (BALF) were measured by enzyme-linked immunosorbent assay (ELISA). Pulmonary histological changes were evaluated by hematoxylin-eosin, myeloperoxidase (MPO) activity in the lung tissue and lung wet/dry weight ratios were observed. Furthermore, the mitogen-activated protein kinases (MAPK) signaling pathway activation and the phosphorylation of IκBα protein were determined by Western blot analysis. Prime-O-glucosylcimifugin showed promising anti-inflammatory effect by inhibiting the activation of MAPK and NF-κB signaling pathway.

Suppression of LPS-induced inflammatory responses by gossypol in RAW 264.7 cells and mouse models.

Gossypol, a yellowish polyphenolic compound originally from cotton plant, has been known to exert a potential for anti-cancer, anti-inflammatory and other important therapeutic activities. The purpose of this investigation was to determine the protection of gossypol on inflammation in Lipopolysaccharide (LPS) stimulated RAW 264.7 cells and LPS induced in vivo lung injury model. The effects of gossypol on pro-inflammatory cytokines and signaling pathways were evaluated by enzyme-linked immunosorbent assay and Western blot. The results showed that gossypol significantly inhibited the production of LPS-induced TNF-α, IL-6 and IL-1ß both in vitro and vivo. Furthermore, gossypol blocked the phosphorylation of IκBα protein, p65, p38, c-Junterminal kinase (JNK) and extracellular signal-regulated kinase (ERK) in LPS stimulated RAW 264.7 cells. From the in vivo study, it was observed that gossypol attenuated lung histopathologic changes in mouse models. The present data suggest that gossypol suppresses the inflammation in vitro and vivo, and may be a potential therapeutic candidate for the treatment of inflammatory disorders.

p-Cymene modulates in vitro and in vivo cytokine production by inhibiting MAPK and NF-κB activation.

The present study was designed to investigate the effects of p-cymene on lipopolysaccharide (LPS)-induced inflammatory cytokine production both in vitro and in vivo. The production of tumor necrosis factor-α (TNF-α), interleukin-1ß (IL-1ß), interleukin-6 (IL-6), and interleukin-10 (IL-10) in LPS-stimulated RAW 264.7 cells and C57BL/6 mice was evaluated by sandwich ELISA. Meanwhile, the mRNA levels of cytokine genes were examined in vitro by semiquantitative RT-PCR. In a further study, we analyzed the activation of nuclear factor-κB (NF-κB) and mitogen-activated protein kinase (MAPK) signaling pathways by western blotting. We found that p-cymene significantly regulated TNF-α, IL-1ß, and IL-6 production in LPS-stimulated RAW 264.7 cells. Furthermore, the levels of relative mRNAs were also found to be downregulated. In in vivo trail, p-cymene markedly suppressed the production of TNF-α and IL-1ß and increased IL-10 secretion. We also found that p-cymene inhibited LPS-induced activation of extracellular signal receptor-activated kinase 1/2, p38, c-Jun N-terminal kinase, and IκBα. These results suggest that p-cymene may have a potential anti-inflammatory action on cytokine production by blocking NF-κB and MAPK signaling pathways.

Anti-inflammatory effects of linalool in RAW 264.7 macrophages and lipopolysaccharide-induced lung injury model.

BACKGROUND: Inflammation, characterized by redness, swelling, pain and a sensation of heat, is one of the body's self-defense systems. Although the inflammation response has an important role in host survival, it also leads to chronic inflammatory diseases. Linalool is a natural compound of the essential oils in several aromatic plants species. It possesses anti-inflammatory, antinociceptive, and other bioactive properties. In the present study, we investigated the protective effects of linalool on inflammation in lipopolysaccharide (LPS)-stimulated RAW 264.7 cells and an LPS-induced in vivo lung injury model. METHODS: We evaluated the effects of linalool on LPS-induced production of inflammatory mediators in Raw 264.7 murine macrophages by enzyme-linked immunosorbent assay and Western blot. To confirm the anti-inflammatory activity of linalool in vivo, we induced an acute lung injury in an LPS-induced mouse model. RESULTS: Linalool attenuated the production of LPS-induced tumor necrosis-α and interleukin-6 both in vitro and in vivo. Furthermore, phosphorylation of IκBα protein, p38, c-Jun terminal kinase, and extracellular signal-regulated kinase in LPS-stimulated RAW 264.7 cells was blocked by linalool. Our in vivo study also found that linalool attenuated lung histopathologic changes in mouse models. CONCLUSIONS: The results suggest that linalool inhibits inflammation both in vitro and in vivo, and may be a potential therapeutic candidate for the treatment of inflammatory diseases.

Suppression of MAPK and NF-κB pathways by limonene contributes to attenuation of lipopolysaccharide-induced inflammatory responses in acute lung injury.

The present study aimed to investigate the protective role of limonene in lipopolysaccharide (LPS)-induced acute lung injury (ALI). ALI was induced in mice by intratracheal instillation of LPS (0.5 mg/kg), and limonene (25, 50, and 75 mg/kg) was injected intraperitoneally 1 h prior to LPS administration. After 12 h, bronchoalveolar lavage fluid (BALF) and lung tissue were collected. Limonene pretreatment at doses of 25, 50, and 75 mg/kg decreased LPS-induced evident lung histopathological changes, lung wet-to-dry weight ratio, and lung myeloperoxidase activity. In addition, pretreatment with limonene inhibited inflammatory cells and proinflammatory cytokines including tumor necrosis factor-α, interleukin-1ß, and interleukin-6 in BALF. Furthermore, we demonstrated that limonene blocked the phosphorylation of IκBα, nuclear factor-κB (NF-κB) p65, p38 mitogen-activated protein kinase (MAPK), c-Jun NH2-terminal kinase, and extracellular signal-regulated kinase in LPS-induced ALI. The results presented here suggest that the protective mechanism of limonene may be attributed partly to decreased production of proinflammatory cytokines through the inhibition of NF-κB and MAPK activation.

Preventive effect of Imperatorin on acute lung injury induced by lipopolysaccharide in mice.

Imperatorin, a linear furanocoumarin, has many pharmacological effects such as antibacterial, anti-inflammatory and antiviral effects. The purpose of this study was to investigate the effect of Imperatorin on lipopolysaccharide (LPS)-induced acute lung injury (ALI) in mice. BALB/c mice were pretreated with Imperatorin 1h before LPS challenge. We found that the levels of tumor necrosis factor-α (TNF-α), interleukin-1ß (IL-1ß) and interleukin-6 (IL-6) in the bronchoalveolar lavage fluid (BALF) were decreased significantly, and the level of interleukin-10 (IL-10) was up-regulated 8h after Imperatorin treatment. Pretreatment with Imperatorin (15 or 30 mg/kg) decreased lung wet-to-dry weight (W/D) ratio, the number of inflammatory cells and myeloperoxidase (MPO) activities. Additionally, Imperatorin attenuated lung histopathological changes and significantly inhibited the phosphorylation of IκB, JNK, ERK and p38/MAPK. These findings demonstrate that Imperatorin protects against LPS-induced ALI in mice.

Kaempferol regulates MAPKs and NF-κB signaling pathways to attenuate LPS-induced acute lung injury in mice.

Recent studies show that mitogen-activated protein kinases (MAPKs) and nuclear factor-kappa B (NF-κB) signaling pathways are two pivotal roles contributing to the development of lipopolysaccharide (LPS)-induced acute lung injury (ALI). The present study aimed to investigate the protective effect of kaempferol (Kae), a naturally occurring flavonoid compound, on ALI and explore its possible mechanisms. Male BALB/c mice with ALI, induced by intranasal instillation of LPS, were treated or not with Kae (100 mg/kg, intragastrically) 1h prior to LPS exposure. Kae treatment attenuated pulmonary edema of mice with ALI after LPS challenge, as it markedly decreased the lung W/D ratio of lung samples, protein concentration and the amounts of inflammatory cells in BALF. Similarly, LPS mediated overproduction of proinflammatory cytokines in BALF, including TNF-α, IL-1ß and IL-6, was strongly reduced by Kae. Histological studies demonstrated that Kae substantially inhibited LPS-induced alveolar wall thickness, alveolar hemorrhage and leukocytes infiltration in lung tissue with evidence of reduced myeloperoxidase (MPO) activity. Kae also efficiently increased superoxide dismutase (SOD) activity of lung sample when compared with LPS group, which was obviously reduced by LPS administration. In addition, Western blot analysis indicated that the activation of MAPKs and NF-κB signaling pathways stimulated by LPS was significantly blocked by Kae. Taken together, our results suggest that Kae exhibits a protective effect on LPS-induced ALI via suppression of MAPKs and NF-κB signaling pathways, which may involve the inhibition of tissue oxidative injury and pulmonary inflammatory process.

Traditional medicine alpinetin inhibits the inflammatory response in Raw 264.7 cells and mouse models.

Alpinetin, one of the main constituents of the seeds of Alpinia katsumadai Hayata, belonging to flavonoids, has been known to exhibit antibacterial, anti-inflammatory and other important therapeutic activities. The purpose of this study was to investigate the protection of alpinetin on inflammation in Lipopolysaccharide (LPS) stimulated Raw 264.7 cells and LPS induced vivo lung injury model. The effects of alpinetin on pro-inflammatory cytokines and signaling pathways were analyzed by enzyme-linked immunosorbent assay and Western blot. The results showed that alpinetin markedly inhibited the LPS- induced TNF-α, IL-6 and IL-1ß production both in vitro and vivo. Furthermore, alpinetin blocked the phosphorylation of IκBα protein, p65, p38 and extracellular signal-regulated kinase (ERK) in LPS stimulated RAW 264.7 cells. From in vivo study, it was also observed that alpinetin attenuated lung histopathologic changes in mouse models. These results suggest that alpinetin potentially decreases the inflammation in vitro and vivo, and might be a therapeutic agent against inflammatory diseases.