Meroterpenoid-Rich Ethanoic Extract of Sargassum macrocarpum Ameliorates Dextran Sulfate Sodium-Induced Colitis in Mice.

Colitis is a colon mucosal disorder characterized by intestinal damage and inflammation. This current study aimed to evaluate the effect of meroterpenoid-rich ethanoic extract of a brown algae, Sargassum macrocarpum (MES) on dextran sulfate sodium (DSS)-induced colitis in mice and explore the possible mechanisms. Mice were given 4% DSS in drinking water for 7 days to induce colitis, followed by 3 days of regular water. MES (12 mg/kg body weight) or celecoxib (10 mg/kg body weight) was administrated orally to mice on a daily basis during these 10 days. Both MES and celecoxib supplementations significantly attenuated DSS-induced weight loss, shortening of colon length, elevated myeloperoxidase activity as well as histomorphological changes of colon. MES and celecoxib reduced the inflammation level of colon tissue, as indicated by its suppression on a panel of pro-inflammatory cytokines, including interleukin (IL)-1ß, IL-17, tumor necrosis factor α, and interferon γ, and a group of inflammatory proteins, including intracellular adhesion molecule 1, vascular adhesion molecule 1, matrix metalloproteinase (MMP)-2, MMP-9, MMP-13, and inducible nitric oxidase. In addition, their administration down-regulated pro-inflammatory cytokines in serum. Moreover, the supplementation of MES suppressed the DSS-induced hyperactivation of Akt, JNK, and NF-κB signaling pathways. Taken together, our results demonstrate that MES ameliorates DSS-induced colitis in mice, suggesting that MES may have therapeutic implications for the treatment of colitis.

Sargahydroquinoic Acid, a Cyclooxygenase-2 Inhibitor, Attenuates Inflammatory Responses by Regulating NF-κB Inactivation and Nrf2 Activation in Lipopolysaccharide-Stimulated Cells.

Sargahydroquinoic acid (SHQA) is a major plastoquinone in Sargassum macrocarpum and has shown the capacity to prevent inflammation and oxidative stress. However, the protective mechanisms were unclear. The molecular mechanisms of SHQA on ameliorating inflammation and oxidative stress have been investigated, using lipopolysaccharide (LPS)-stimulated macrophages. SHQA was isolated and purified from S. macrocarpum and the anti-inflammatory mechanisms were explored using LPS-stimulated murine macrophage RAW 264.7 cells. SHQA did not change the expression of cyclooxygenase-2 (COX-2) but inhibited the activity of COX-2. As a result, SHQA significantly diminished the secretions of nitric oxide (NO), prostaglandin E2 (PGE2), and multiple pro-inflammatory cytokines. LPS-induced activation of nuclear factor-κB (NF-κB) was inhibited by SHQA by preventing the degradation of inhibitor κB-α (IκBα). NF-κB activation was also downregulated by the inhibition of Akt phosphorylation in LPS-stimulated cells. Furthermore, SHQA induced the expression of heme oxygenase 1 via Nrf2 activation. These results indicated that SHQA inhibited LPS-induced expressions of inflammatory mediators via suppressing the Akt-mediated NF-κB pathway as well as upregulating the Nrf2/HO-1 pathway. Our findings suggest that SHQA might be a potential therapeutic agent in various inflammatory diseases.

Meroterpenoid-Rich Fraction of the Ethanol Extract of Sargassum Serratifolium Suppresses Collagen-Induced Rheumatoid Arthritis in DBA/1J Mice Via Inhibition of Nuclear Factor κB Activation.

SCOPE: Rheumatoid arthritis (RA) is an autoimmune disorder related to the inflammation of cartilage due to the infiltration of inflammatory cells. Sargassum serratifolium, a brown alga, possesses strong anti-inflammatory activities. METHODS AND RESULTS: The effect of meroterpenoid-rich fraction from the ethanol extract of S. serratifolium (MES) on RA and its underlying mechanisms on the inhibition of RA using a collagen-induced arthritis (CIA) mouse model are examined. The results show that MES ameliorates paw swelling and reduces the arthritis score. MES considerably decreases the secretion of pro-inflammatory cytokines in the serum and joint tissue of mice. Histopathological analysis demonstrates that MES strongly inhibited bone damage and inflammatory cell intrusion in the joint tissue. The expression of inflammatory enzymes and adhesion molecules is significantly inhibited in the serum and joint tissue of MES-fed mice. In addition, MES downregulates the nuclear factor κB (NF-κB) signaling pathway by suppressing the phosphorylation of protein kinase B, c-Jun N-terminal kinase, and p38 mitogen-activated protein kinases. CONCLUSIONS: MES supplementation remarkably reduces inflammatory response in CIA mouse model. These results indicate that MES can be used as a pharmaceutical agent against RA.

Protective effects of flavonoids isolated from Korean milk thistle Cirsium japonicum var. maackii (Maxim.) Matsum on tert-butyl hydroperoxide-induced hepatotoxicity in HepG2 cells.

ETHNOPHARMACOLOGICAL RELEVANCE: Milk thistle leaves and flowers have been traditionally used as herbal remedy to alleviate liver diseases for decades. Korean milk thistle, Cirsium japonicum var. maackii (Maxim.) Matsum has been employed in traditional folk medicine as diuretic, antiphlogistic, hemostatic, and detoxifying agents. AIM OF THE STUDY: The aim of current investigation was to evaluate hepatoprotective properties of the MeOH extract of the roots, stems, leaves and flowers of Korean milk thistle as well as four isolated flavonoids, luteolin, luteolin 5-O-glucoside, apigenin and apigenin 7-O-glucuronide during t-BHP-induced oxidative stress in HepG2 cells. MATERIALS AND METHODS: Hepatoprotective potential of the MeOH extracts and flavonoids derived from Korean milk thistle against t-BHP-induced oxidative stress in HepG2 cells were evaluated following MTT method. Incubating HepG2 cells with t-BHP markedly decreased the cell viability and increased the intracellular ROS generation accompanied by depleted GSH levels. Protein expression of heme oxygenase (HO-1) and nuclear factor-E2-related factor 2 (Nrf-2) was determined by Western blot. RESULTS: Our findings revealed that pretreating HepG2 cells with MeOH extracts and bioactive flavonoids significantly attenuated the t-BHP-induced oxidative damage, followed by increased cell viability in a dose-dependent manner. The results illustrate that excess ROS generation was reduced and GSH levels increased dose-dependently when HepG2 cells were pretreated with four flavonoids. Moreover, Western blotting analysis demonstrated that protein expressions of Nrf-2 and HO-1 were also up-regulated by flavonoids treatment. CONCLUSIONS: These results clearly demonstrate that the MeOH extracts and flavonoids from Korean milk thistle protected HepG2 cells against oxidative damage triggered by t-BHP principally by modulating ROS generation and restoring depleted GSH levels in addition to the increased Nrf-2/HO-1 signaling cascade. These flavonoids are potential natural antioxidative biomarkers against oxidative stress-induced hepatotoxicity.

Sargachromenol protects against vascular inflammation by preventing TNF-α-induced monocyte adhesion to primary endothelial cells via inhibition of NF-κB activation.

Vascular inflammation is a key factor in the pathogenesis of atherosclerosis. The purpose of this study was to investigate the protective effects of sargachromenol (SCM) against tumor necrosis factor (TNF)-α-induced vascular inflammation. SCM decreased the expression of cell adhesion molecules, including intracellular adhesion molecule-1 and vascular cell adhesion molecule-1, in TNF-α-stimulated human umbilical vein endothelial cells (HUVECs), resulted in reduced adhesion of monocytes to HUVECs. SCM also decreased the production of monocyte chemoattractant protein-1 and matrix metalloproteinase-9 in TNF-α-induced HUVECs. Additionally, SCM inhibited activation of nuclear factor kappa B (NF-κB) induced by TNF-α through preventing the degradation of inhibitor kappa B. Moreover, SCM reduced the production of reactive oxygen species in TNF-α-treated HUVECs. Overall, SCM alleviated vascular inflammation through the regulation of NF-κB activation and through its intrinsic antioxidant activity in TNF-α-induced HUVECs. These results indicate that SCM may have potential application as a therapeutic agent against vascular inflammation.

6,6'-Bieckol suppresses inflammatory responses by down-regulating nuclear factor-κB activation via Akt, JNK, and p38 MAPK in LPS-stimulated microglial cells.

OBJECTIVE: Microglial activation has been implicated in many neurological disorders for its inflammatory and neurotrophic effects. In this study, we investigated the pharmaceutical properties of 6,6'-bieckol on the regulation of nuclear factor-κB (NF-κB) activation responsible to the expression of inducible nitric oxide synthase (iNOS) and cyclooxygenase (COX)-2 using lipopolysaccharide (LPS)-stimulated BV2 and murine primary microglial cells. Meterials and methods: The levels of nitric oxide (NO), prostaglandin E2 (PGE)2, and pro-inflammatory cytokines were measured by Griess assay and enzyme-linked immunosorbent assay. The levels of iNOS, COX-2, mitogen-activated protein kinases (MAPKs), and Akt were measured using Western blot. Nuclear translocation and transcriptional activation of NF-κB were determined by immunofluorescence and reporter gene assay, respectively. RESULTS: We found that 6,6'-bieckol decreased the expression of iNOS and COX-2 as well as pro-inflammatory cytokines in LPS-stimulated BV2 and primary microglial cells in a dose-dependent manner. 6,6'-Bieckol inhibited activation of NF-κB by preventing the degradation of inhibitor κB (IκB)-α and led to prevent the nuclear translocation of NF-κB/p65 subunit. Moreover, 6,6'-bieckol inhibited the phosphorylation of Akt, JNK, and p38 MAPK. DISCUSSION AND CONCLUSION: These results indicate that the anti-inflammatory effect of 6,6'-bieckol on LPS-stimulated microglial cells is mainly regulated by the inhibition of IκB-α/NF-κB and JNK/p38 MAPK/Akt pathways, supporting biochemical characteristics of the compound for therapeutic agent against neuroinflammatory diseases caused by microglial activation.

Sargaquinoic acid attenuates inflammatory responses by regulating NF-κB and Nrf2 pathways in lipopolysaccharide-stimulated RAW 264.7 cells.

Myagropsis myagroides, a brown alga, showed strong anti-inflammatory activities in the previous studies. In this study, we isolated a strong anti-inflammatory compound, sargaquinoic acid (SQA), from M. myagroides and investigated the anti-inflammatory action using lipopolysaccharide (LPS)-stimulated RAW 264.7 cells. SQA suppressed the production of inducible nitric oxide synthase and cyclooxygenase-2 in LPS-stimulated cells as well as that of reactive oxygen species. As a result, SQA inhibited the production of NO, prostaglandin E2, and pro-inflammatory cytokines. LPS-induced transcriptional activation of nuclear factor-κB (NF-κB) was remarkably inhibited by SQA treatment through the prevention of inhibitor κB-α degradation. The regulation of NF-κB activation was also mediated by the phosphorylation of ERK and Akt in LPS-stimulated RAW 264.7 cells. Moreover, SQA induced the production of heme oxygenase 1 via activation of transcription factor Nrf2. These results indicate that SQA inhibits the LPS-induced expression of inflammatory mediators via suppression of ERK and Akt-mediated NF-κB pathway as well as up-regulation of Nrf2/HO-1 pathway, indicating that SQA has a potential therapeutic and preventive application in various inflammatory diseases.

Sargaquinoic Acid Inhibits TNF-α-Induced NF-κB Signaling, Thereby Contributing to Decreased Monocyte Adhesion to Human Umbilical Vein Endothelial Cells (HUVECs).

Sargaquinoic acid (SQA) has been known for its antioxidant and anti-inflammatory properties. This study investigated the effects of SQA isolated from Sargassum serratifolium on the inhibition of tumor necrosis factor (TNF)-α-induced monocyte adhesion to human umbilical vein endothelial cells (HUVECs). SQA decreased the expression of cell adhesion molecules such as intracellular adhesion molecule-1 and vascular cell adhesion molecule-1 as well as chemotactic cytokines such as interleukin-8 and monocyte chemoattractant protein-1 in TNF-α-treated HUVECs. As a result, SQA prevented monocyte adhesion to TNF-α-induced adhesion. SQA also inhibited TNF-α-induced nuclear factor kappa B (NF-κB) translocation into the nucleus by preventing proteolytic degradation of inhibitor κB-α. Overall, SQA protects against TNF-α-induced vascular inflammation through inhibition of the NF-κB pathway in HUVECs. These data suggest that SQA may be used as a therapeutic agent for vascular inflammatory diseases such as atherosclerosis.

Anti-inflammatory effects of sargachromenol-rich ethanolic extract of Myagropsis myagroides on lipopolysaccharide-stimulated BV-2 cells.

BACKGROUND: Excessive pro-inflammatory cytokine production from activated microglia contributes to neurodegenerative diseases, thus, microglial inactivation may delay the progress of neurodegeneration by attenuating the neuroinflammation. Among 5 selected brown algae, we found the highest antioxidant and anti-neuroinflammatory activities from Myagropsis myagroides ethanolic extract (MME) in lipopolysaccharide (LPS)-stimulated BV-2 cells. METHODS: The levels of nitric oxide (NO), prostaglandin E2 (PGE2), and pro-inflammatory cytokines were measured by Griess assay and enzyme linked immunesorbent assay. The levels of inducible nitric oxide synthase (iNOS), cyclooxygenase-2 (COX-2), mitogen-activated protein kinases (MAPKs), and Akt were measured using Western blot. Nuclear translocation and transcriptional activation of nuclear factor-κB (NF-κB) were determined by immunefluorescence and reporter gene assay, respectively. RESULTS: MME inhibited the expression of iNOS and COX-2 at mRNA and protein levels, resulting in reduction of NO and PGE2 production. As a result, pro-inflammatory cytokines were reduced by MME. MME also inhibited the activation and translocation of NF-κB by preventing inhibitor κB-α (IκB-α) degradation. Moreover, MME inhibited the phosphorylation of extracellular signal regulated kinases (ERKs) and c-Jun N-terminal kinases (JNKs). Main anti-inflammatory compound in MME was identified as sargachromenol by NMR spectroscopy. CONCLUSIONS: These results indicate that the anti-inflammatory effect of sargachromenol-rich MME on LPS-stimulated microglia is mainly regulated by the inhibition of IκB-α/NF-κB and ERK/JNK pathways.

Hexane fraction from Sargassum fulvellum inhibits lipopolysaccharide-induced inducible nitric oxide synthase expression in RAW 264.7 cells via NF-κB pathways.

Sargassum fulvellum (Turner) C. Agardh has been used to treat various inflammatory diseases, including lump, dropsy, swollen and painful scrotum, and urination problems for several centuries with no side effects. This study aims to investigate the anti-inflammatory effect of the hexane fraction of S. fulvellum (HFS) in lipopolysaccharide (LPS)-stimulated RAW 264.7 cells and phorbol 12-myristate 13-acetate (PMA)-induced mouse-ear edema. The anti-inflammatory activity of HFS in LPS-stimulated RAW 264.7 cells was investigated by assessing the inhibition of nitric oxide (NO) and pro-inflammatory cytokine production during Griess reaction and enzyme-linked immunosorbent assay (ELISA), respectively. The molecular mechanisms that underlie the anti-inflammatory action of HFS were investigated by analyzing the activation of transcription factor and its upstream signaling proteins. Additionally, an in vivo study of the anti-inflammatory effect of HFS was carried out using PMA-induced mouse-ear edema. HFS inhibited LPS-induced NO production in a dose-dependent manner and suppressed the expression of inducible NO synthase (iNOS) in the RAW 264.7 cells. Further, HFS reduced the production of pro-inflammatory cytokines in the LPS-stimulated RAW 264.7 cells. HFS significantly inhibited LPS-induced nuclear factor kappa B (NF-κB) transcriptional activity and NF-κB translocation into the nucleus by preventing degradation of inhibitor κB-α. Moreover, HFS inhibited the activation of Akt and mitogen-activated protein kinases (MAPKs) in the LPS-stimulated RAW 264.7 cells. Furthermore, HFS suppressed PMA-induced mouse-ear edema. The above data indicate that the anti-inflammatory effects of HFS on LPS-stimulated cells are associated with the suppression of NF-κB through the inhibition of MAPKs and Akt phosphorylation.