Narirutin-Rich Celluclast Extract from Mandarin (Citrus unshiu) Peel Alleviates High-Fat Diet-Induced Obesity and Promotes Energy Metabolism in C57BL/6 Mice.

Mandarin peel, a main by-product from the processing of citrus juice, has been highlighted for its various bioactivities and functional ingredients. Our previous study proved the inhibitory effects of Celluclast extract from mandarin peel (MPCE) on lipid accumulation and differentiation in 3T3-L1 adipocytes. Therefore, the current study aimed to evaluate the anti-obesity effect of MPCE in high-fat diet (HFD)-induced obese mice. The high-performance liquid chromatography (HPLC) analysis exhibited that narirutin and hesperidin are the main active components of MPCE. Our current results showed that MPCE supplementation decreased adiposity by reducing body and organ weights in HFD-induced obese mice. MPCE also reduced triglyceride (TG), alanine transaminase (ALT), aspartate transaminase (AST), and leptin contents in the serum of HFD-fed mice. Moreover, MPCE significantly inhibited hepatic lipid accumulation by regulating the expression levels of proteins associated with lipid metabolism, including sterol regulatory element-binding protein (SREBP1c), fatty acid synthase (FAS), and acetyl-CoA carboxylase (ACC). Furthermore, MPCE administration significantly inhibited both adipogenesis and lipogenesis, with modulation of energy metabolism by activating 5' adenosine monophosphate-activated protein kinase (AMPK) and lipolytic enzymes such as hormone-sensitive lipase (HSL) in the white adipose tissue (WAT). Altogether, our findings indicate that MPCE improves HFD-induced obesity and can be used as a curative agent in pharmaceuticals and nutraceuticals to alleviate obesity and related disorders.

Purification and Molecular Docking Study on the Angiotensin I-Converting Enzyme (ACE)-Inhibitory Peptide Isolated from Hydrolysates of the Deep-Sea Mussel Gigantidas vrijenhoeki.

The objective of this study was to prepare an angiotensin I-converting enzyme (ACE)-inhibitory peptide from the hydrothermal vent mussel, Gigantidas vrijenhoeki. The G. vrijenhoeki protein was hydrolyzed by various hydrolytic enzymes. The peptic hydrolysate exhibited the highest ACE-inhibitory activity and was fractionated into four molecular weight ranges by ultrafiltration. The <1 kDa fraction exhibited the highest ACE inhibitory activity and was found to have 11 peptide sequences. Among the analyzed peptides, KLLWNGKM exhibited stronger ACE inhibitory activity and an IC50 value of 0.007 µM. To investigate the ACE-inhibitory activity of the analyzed peptides, a molecular docking study was performed. KLLWNGKM exhibited the highest binding energy (-1317.01 kcal/mol), which was mainly attributed to the formation of hydrogen bonds with the ACE active pockets, zinc-binding motif, and zinc ion. These results indicate that G. vrijenhoeki-derived peptides can serve as nutritional and pharmacological candidates for controlling blood pressure.

Antioxidant, Antiviral, and Anti-Inflammatory Activities of Lutein-Enriched Extract of Tetraselmis Species.

Microalgae are proposed to have powerful applications for human health in the pharmaceutical and food industries. Tetraselmis species (sp.), which are green microalgae, were identified as a source of broad-spectrum health-promoting biological activities. However, the bioactivity of these species has not been elucidated. We aimed to confirm the antioxidant, antiviral, and anti-inflammatory effects of Tetraselmis sp. extract (TEE). TEE showed 2,2-diphenyl-1-picryl-hydrazyl-hydrate radical and hydrogen peroxide scavenging activities and reduced plaque formation in Vero E6 cells infected with vaccinia virus. TEE treatment also significantly inhibited nitric oxide (NO) production and improved cell viability in lipopolysaccharide (LPS)-induced RAW264.7 cells. These anti-inflammatory effects were further analyzed in LPS-induced RAW 264.7 cells and the zebrafish model. Further, TEE reduced induced NO synthase expression and proinflammatory cytokine release, including tumor necrosis factor-α, interleukin-6, and interleukin-1ß, through MAPKs and NF-κB-dependent mechanisms. Further analysis revealed that TEE increased the survival rate and reduced cell death and NO production in an LPS-stimulated zebrafish model. Further, high-performance liquid chromatography revealed a strong presence of the carotenoid lutein in TEE. Overall, the results suggest that lutein-enriched TEE may be a potent antioxidant, antiviral, and anti-inflammatory agent that could be sustainably utilized in industrial applications.

Radio-protective effects of Thymus quinquecostatus Celak extract in mice.

Thymus quinquecostatus Celak (TQC) is an aromatic herb, that possesses a wide range of biological properties. In the present study, we investigated the radio-protective effect of TQC water extract (TQCW) in gamma ray-exposed splenocytes, a peripheral immune cell and mice. Our results showed that the treatment with TQCW dose-dependently increased the viability of splenocytes. TQCW significantly increased the proliferation of splenocytes by reducing the production of intracellular reactive oxygen species (ROS) in 2 Gy-exposed splenocytes. Moreover, TQCW enhanced the hemopoietic system as increasing the number of endogenous spleen colony-forming units, and the number and the proliferation of splenocytes in 7 Gy-exposed mice. These results suggest that TQCW protects mice by enhancing the splenocytes proliferation and hemopoietic systems following exposure to gamma rays.

Structure Characterization and Antihypertensive Effect of an Antioxidant Peptide Purified from Alcalase Hydrolysate of Velvet Antler.

Recently, interest in food-derived bioactive peptides as promising ingredients for the prevention and improvement of hypertension is increasing. The purpose of this study was to determine the structure and antihypertensive effect of an antioxidant peptide purified from velvet antler in a previous study and evaluate its potential as a various bioactive peptide. Molecular weight (MW) and amino acid sequences of the purified peptide were determined by quadrupole time-of-flight electrospray ionization mass spectroscopy. The angiotensin I-converting enzyme (ACE) inhibition activity of the purified peptide was assessed by enzyme reaction methods and in silico molecular docking analysis to determine the interaction between the purified peptide and ACE. Also, antihypertensive effect of the purified peptide in spontaneously hypertensive rats (SHRs) was investigated. The purified antioxidant peptide was identified to be a pentapeptide Asp-Asn-Arg-Tyr-Tyr with a MW of 730.31 Da. This pentapeptide showed potent inhibition activity against ACE (IC50 value, 3.72 µM). Molecular docking studies revealed a good and stable binding affinity between purified peptide and ACE and indicated that the purified peptide could interact with HOH2570, ARG522, ARG124, GLU143, HIS387, TRP357, and GLU403 residues of ACE. Furthermore, oral administration of the pentapeptide significantly reduced blood pressure in SHRs. The pentapeptide derived from enzymatic hydrolysate of velvet antler is an excellent ACE inhibitor. It might be effectively applied as an animal-based functional food ingredient.

Identifying Potential Antioxidant Properties from the Viscera of Sea Snails (Turbo cornutus).

Turbo cornutus, the horned turban sea snail, is found along the intertidal and basaltic shorelines of Jeju Island, Korea. T. cornutus feeds on seaweeds (e.g., Undaria sp., and Ecklonia sp.) composed of diverse antioxidants. This study identified potential antioxidant properties from T. cornutus viscera tissues. Diverse extracts were evaluated for their hydrogen peroxide (H2O2) scavenging activities. T. cornutus viscera protamex-assisted extracts (TVP) were purified by gel filtration chromatography (GFC), and potential antioxidant properties were analyzed for their amino acid sequences and its peroxidase inhibition effects by in silico molecular docking and in vitro analysis. According to the results, T. cornutus viscera tissues are composed of many protein contents with each over 50%. Among the extracts, TVP possessed the highest H2O2 scavenging activity. In addition, TVP-GFC-3 significantly decreased intracellular reactive oxygen species (ROS) levels and increased cell viability in H2O2-treated HepG2 cells without cytotoxicity. TVP-GFC-3 comprises nine low molecular bioactive peptides (ELR, VGPQ, TDY, ALPHA, PAH, VDY, WSDK, VFSP, and FAPQY). Notably, the peptides dock to the active site of the myeloperoxidase (MPO), especially TDY and FAPQY showed the MPO inhibition effects with IC50 values of 646.0 ± 45.0 µM and 57.1 ± 17.7 µM, respectively. Altogether, our findings demonstrated that T. cornutus viscera have potential antioxidant properties that can be used as high value-added ingredients.

Diphlorethohydroxycamalol isolated from Ishige okamurae prevents H2O2-induced oxidative damage via BMP2/Runx2 signaling in osteoblastic MC3T3-E1 cells.

Accumulating evidence has shown an association between osteoporosis and oxidative damage. In the present study, the protective effects of diphlorethohydroxycarmalol (DPHC) isolated from the brown algae Ishige okamurae against H2O2-induced oxidative damage via bone morphogenetic protein 2 (BMP2)/ runt-related transcription factor 2 (Runx2) signaling were investigated using MC3T3-E1 osteoblastic cells. DPHC counteracted the reduction in cell viability caused by H2O2 exposure and protected against H2O2-induced dysfunction, demonstrated by improved cellular alkaline phosphatase (ALP) activity and calcium deposition. In addition, treatment with 0.05-0.2 mM DPHC elevated the protein expression of osteoblast differentiation factors type 1 collagen, ALP, p-Smad1/5, Osterix, BMP2, and Runx2, in response to H2O2-induced oxidative damage. Importantly, DPHC decreased the expression levels of receptor activator of nuclear factor kappa-B ligand, which promotes bone resorption, and inhibited the H2O2-induced generation of reactive oxygen species. Taken together, the results suggest that DPHC counteracts the effects of oxidative stress in osteoblastic cells and has the potential to be effective in preventing and alleviating osteoporosis.

Protocatechuic Aldehyde Inhibits α-MSH-Induced Melanogenesis in B16F10 Melanoma Cells via PKA/CREB-Associated MITF Downregulation.

Protocatechuic aldehyde (PA) is a naturally occurring phenolic compound that is a potent inhibitor of mushroom tyrosinase. However, the molecular mechanisms of the anti-melanogenesis activity of PA have not yet been reported. The aim of the current study was to clarify the melanogenesis inhibitory effects of PA and its molecular mechanisms in murine melanoma cells (B16F10). We first predicted the 3D structure of tyrosinase and used a molecular docking algorithm to simulate binding between tyrosinase and PA. These molecular modeling studies calculated a binding energy of -527.42 kcal/mol and indicated that PA interacts with Cu400 and 401, Val283, and His263. Furthermore, PA significantly decreased α-MSH-induced intracellular tyrosinase activity and melanin content in a dose-dependent manner. PA also inhibited key melanogenic proteins such as tyrosinase, tyrosinase-related protein 1 (TRP-1), and TRP-2 in α-MSH-stimulated B16F10 cells. In addition, PA decreased MITF expression levels by inhibiting phosphorylation of cAMP response element-binding protein (CREB) and cAMP-dependent protein kinase A (PKA). These results demonstrate that PA can effectively suppress melanin synthesis in melanoma cells. Taken together, our results show that PA could serve as a potential inhibitor of melanogenesis, and hence could be explored as a possible skin-lightening agent.

Effects of Ethanol Extracts from Grateloupia elliptica, a Red Seaweed, and Its Chlorophyll Derivative on 3T3-L1 Adipocytes: Suppression of Lipid Accumulation through Downregulation of Adipogenic Protein Expression.

Grateloupia elliptica (G. elliptica) is a red seaweed with antioxidant, antidiabetic, anticancer, anti-inflammatory, and anticoagulant activities. However, the anti-obesity activity of G. elliptica has not been fully investigated. Therefore, the effect of G. elliptica ethanol extract on the suppression of intracellular lipid accumulation in 3T3-L1 cells by Oil Red O staining (ORO) was evaluated. Among the eight red seaweeds tested, G. elliptica 60% ethanol extract (GEE) exhibited the highest inhibition of lipid accumulation. GEE was the only extract to successfully suppress lipid accumulation among ethanol extracts from eight red seaweeds. In this study, we successfully isolated chlorophyll derivative (CD) from the ethyl acetate fraction (EA) of GEE by high-performance liquid chromatography and evaluated their inhibitory effect on intracellular lipid accumulation in 3T3-L1 adipocytes. CD significantly suppressed intracellular lipid accumulation. In addition, CD suppressed adipogenic protein expression such as sterol regulatory element-binding protein-1 (SREBP-1), peroxisome proliferator-activated receptor-γ (PPAR-γ), CCAAT/enhancer-binding protein-α (C/EBP-α), and fatty acid binding protein 4 (FABP4). Taken together, our results indicate that CD from GEE inhibits lipid accumulation by suppressing adipogenesis via the downregulation of adipogenic protein expressions in the differentiated adipocytes. Therefore, chlorophyll from G. elliptica has a beneficial effect on lipid metabolism and it could be utilized as a potential therapeutic agent for preventing obesity.

Diphlorethohydroxycarmalol inhibits melanogenesis via protein kinase A/cAMP response element-binding protein and extracellular signal-regulated kinase-mediated microphthalmia-associated transcription factor downregulation in α-melanocyte stimulating hormone-stimulated B16F10 melanoma cells and zebrafish.

Diphlorethohydroxycarmalol (DPHC) is a marine polyphenolic compound derived from brown alga Ishige okamurae. A previously study has suggested that DPHC possesses strong mushroom tyrosinase inhibitory activity. However, the anti-melanogenesis effect of DPHC has not been reported at cellular level. The objective of the present study was to clarify the melanogenesis inhibitory effect of DPHC and its molecular mechanisms in murine melanoma cells (B16F10) and zebrafish model. DPHC significantly inhibited tyrosinase activity and melanin content dose-dependently in α-melanocyte stimulating hormone (α-MSH)-stimulated B16F10 cells. This polyphenolic compound also suppressed the expression of phosphorylation of cAMP response element-binding protein (CREB) by attenuating phosphorylation of cAMP-dependent protein kinase A, resulting in decreased MITF expression levels. Furthermore, DPHC downregulated MITF protein expression levels by promoting the phosphorylation of extracellular signal-regulated kinase. It also inhibited tyrosinase, tyrosinase-related protein 1 (TRP-1), and TRP-2 in α-MSH stimulated B16F10 cells. In in vivo studies using zebrafish, DPHC also markedly inhibited melanin synthesis in a dose-dependent manner. These results demonstrate that DPHC can effectively inhibit melanogenesis in melanoma cells in vitro and in zebrafish in vivo, suggesting that DPHC could be applied in fields of pharmaceutical and cosmeceuticals as a skin-whitening agent. Significance of study: The present study showed for the first time that DPHC could inhibit a-MSH-stimulated melanogenesis via PKA/CREB and ERK pathway in melanoma cells. It also could inhibit pigmentation in vivo in a zebrafish model. This evidence suggests that DPHC has potential as a skin whitening agent. Taken together, DPHC could be considered as a novel anti-melanogenic agent to be applied in cosmetic, food, and medical industry.

Anti-Obesity Effect of Diphlorethohydroxycarmalol Isolated from Brown Alga Ishige okamurae in High-Fat Diet-Induced Obese Mice.

Diphlorethohydroxycarmalol (DPHC) is one of the most abundant bioactive compounds in Ishige okamurae. The previous study suggested that DPHC possesses strong in vitro anti-obesity activity in 3T3-L1 cells. However, the in vivo anti-obesity effect of DPHC has not been determined. The current study explored the effect of DPHC on high-fat diet (HFD)-induced obesity in C57BL/6J mice. The results indicated that oral administration of DPHC (25 and 50 mg/kg/day for six weeks) significantly and dose-dependently reduced HFD-induced adiposity and body weight gain. DPHC not only decreased the levels of triglyceride, low-density lipoprotein cholesterol, leptin, and aspartate transaminase but also increased the level of high-density lipoprotein cholesterol in the serum of HFD mice. In addition, DPHC significantly reduced hepatic lipid accumulation by reduction of expression levels of the critical enzymes for lipogenesis including SREBP-1c, FABP4, and FAS. Furthermore, DPHC remarkably reduced the adipocyte size, as well as decreased the expression levels of key adipogenic-specific proteins and lipogenic enzymes including PPARγ, C/EBPα, SREBP-1c, FABP4, and FAS, which regulate the lipid metabolism in the epididymal adipose tissue (EAT). Further studies demonstrated that DPHC significantly stimulated the phosphorylation of adenosine monophosphate-activated protein kinase (AMPK) and acetyl-CoA carboxylase (ACC) in both liver and EAT. These results demonstrated that DPHC effectively prevented HFD-induced obesity and suggested that DPHC could be used as a potential therapeutic agent for attenuating obesity and obesity-related diseases.

Protective Effects of Novel Antioxidant Peptide Purified from Alcalase Hydrolysate of Velvet Antler Against Oxidative Stress in Chang Liver Cells in Vitro and in a Zebrafish Model In Vivo.

Velvet antler has a long history in traditional medicine. It is also an important healthy ingredient in food as it is rich in protein. However, there has been no report about antioxidant peptides extracted from velvet antler by enzymatic hydrolysis. Thus, the objective of this study was to hydrolyze velvet antler using different commercial proteases (Acalase, Neutrase, trypsin, pepsin, and α-chymotrypsin). Antioxidant activities of different hydrolysates were investigated using peroxyl radical scavenging assay by electron spin resonance spectrometry. Among all enzymatic hydrolysates, Alcalase hydrolysate exhibited the highest peroxyl radical scavenging activity. Alcalase hydrolysate was then purified using ultrafiltration, gel filtration, and reverse-phase high performance liquid chromatography. The purified peptide was identified to be Trp-Asp-Val-Lys (tetrapeptide) with molecular weight of 547.29 Da by Q-TOF ESI mass spectroscopy. This purified peptide exhibited strong scavenging activity against peroxyl radical (IC50 value, 0.028 mg/mL). In addition, this tetrapeptide showed significant protection ability against AAPH-induced oxidative stress by inhibiting of reactive oxygen species (ROS) generation in Chang liver cells in vitro and in a zebrafish model in vivo. This research suggests that the tetrapeptide derived from Alcalase-proteolytic hydrolysate of velvet antler are excellent antioxidants and could be effectively applied as functional food ingredients and pharmaceuticals.

Free radical scavenging activity of the peptide from the Alcalase hydrolysate of the edible aquacultural seahorse (Hippocampus abdominalis).

Seahorses, Hippocampus abdominalis, have a long history in traditional Chinese medicine as an important healthy ingredient in foods. This study evaluated the antioxidant activity of an enzymatic hydrolysate prepared from a seahorse bred in Jeju, South Korea. Experiments were performed in vitro using electron spin resonance spectrometry (ESR) to determine the free radical scavenging activity and in vivo using a zebrafish model to determine the protective effects against 2,2-azobis hydrochloride (AAPH)-induced oxidative damage. H. abdominalis protein hydrolysate (HPH) exhibited peroxyl radical scavenging activity (IC50  = 0.58 mg/ml) generated by the water-soluble AAPH (azo initiator of peroxyl radicals). HPH reduced dose-dependently both intracellular reactive oxygen species (ROS) levels in AAPH-induced cells and cell death in AAPH-induced zebrafish embryos. The antioxidant peptide purified from HPH was identified as a tripeptide (alanine-glycine-aspartic acid) using Q-TOF ESI mass spectroscopy. Thus, this study demonstrated that HPH contains antioxidant peptides that exhibit a strong antioxidant activity. PRACTICAL APPLICATIONS: Hippocampus abdominalis is one of the largest seahorse species and cultivated in many countries. Because of its large body size compared to other seahorse species, H. abdominalis has acquired considerable consumer attraction in the global market. Owing to its biologically useful properties, it recently gained attention as the natural products obtained from H. abdominalis have varied applications in the field of medicine, health care products, and functional foods. Thus, commercial products of this particular seahorse species are popular among customers, especially in China. The purpose of this study was to evaluate the antioxidant property of H. abdominalism, cultured in a commercial seahorse farm in Jeju Island. Owing to its prominent antioxidant activity, it could be used as an ingredient in medicinal preparations, nutraceuticals, and functional foods.

Apoptotic and antiproliferative effects of Stigmast-5-en-3-ol from Dendronephthya gigantea on human leukemia HL-60 and human breast cancer MCF-7 cells.

The genus Dendronephthya encompasses marine soft corals that produce a wide spectrum of biofunctional terpenoids. Anticancer properties of these metabolites are widely exploited as potential chemotherapeutic agents. The present study reports the purification and isolation of a potential antiproliferative constituent, stigmast-5-en-3-ol from the 70% ethanol extract of the soft coral Dendronephthya gigantea. Among several other 3ß-hydroxy-Δ5-steroidal congeners, stigmast-5-en-3-ol indicated prominent antiproliferative effects on HL-60 (leukemia) and MCF-7 (breast cancer) cell lines with IC50 values of 37.82 and 45.17 µg/ml respectively. Stigmast-5-en-3-ol increased apoptotic body formation, accumulation of sub G1 apoptotic cells, and DNA damage in HL-60 and MCF-7 cells. It increased the expression of Bax, caspases, and PARP cleavage while decreasing Bcl-xL levels in both cancer cell lines indicating that the effects are arbitrated via the mitochondria-mediated apoptotic pathway. Steroidal derivatives were identified by GC MS/MS and the identity of stigmast-5-en-3-ol was confirmed by NMR spectra. The present study suggests that stigmast-5-en-3-ol could be a promising candidate for anticancer drug research.

3-Chloro-4,5-dihydroxybenzaldehyde inhibits adipogenesis in 3T3-L1 adipocytes by regulating expression of adipogenic transcription factors and AMPK activation.

Obesity is a serious health issue in many industrialized countries. It is a medical condition with excessive levels of fat accumulated in adipocytes. The objective of the present study was to determine the inhibitory effect of 3-chloro-4,5-dihydroxybenzaldehyde (CDB) on adipogenesis in 3T3-L1 adipocyte cells. CDB suppressed the differentiation and decreased lipid accumulation and triglycerides contents in 3T3-L1 adipocytes. Its suppression effect on fat accumulation was mediated via expression of adipogenesis factors (C/EBPα, SREBP-1c, PPARγ, and adiponectin) during adipocyte differentiation in white adipocyte cells. CDB's ability to suppress fat accumulation was increased in a concentration-dependent manner. It inhibited fatty acid synthesis related proteins including FAS, FABP4, leptin, and perilipin. It also increased expression of phosphorylated AMPK in adipocytes cells. These observations suggest that CDB has potential anti-obesity effect with ability to improve metabolic diseases.

Tuberatolide B Suppresses Cancer Progression by Promoting ROS-Mediated Inhibition of STAT3 Signaling.

Tuberatolide B (TTB, C27H34O4) is a diastereomeric meroterpenoid isolated from the Korean marine algae Sargassum macrocarpum. However, the anticancer effects of TTB remain unknown. In this study, we demonstrate that TTB inhibits tumor growth in breast, lung, colon, prostate, and cervical cancer cells. To examine the mechanism by which TTB suppresses cell growth, we determined the effect of TTB on apoptosis, ROS generation, DNA damage, and signal transduction. TTB induced ROS production in MDA-MB-231, A549, and HCT116 cells. Moreover, TTB enhanced DNA damage by inducing γH2AX foci formation and the phosphorylation of DNA damage-related proteins such as Chk2 and H2AX. Furthermore, TTB selectively inhibited STAT3 activation, which resulted in a reduction in cyclin D1, MMP-9, survivin, VEGF, and IL-6. In addition, TTB-induced ROS generation caused STAT3 inhibition, DNA damage, and apoptotic cell death. Therefore, TTB suppresses cancer progression by promoting ROS-mediated inhibition of STAT3 signaling, suggesting that TTB is useful for the treatment of cancer.

A sulfated polysaccharide of Ecklonia cava inhibits the growth of colon cancer cells by inducing apoptosis.

We investigated anticancer effects of the crude polysaccharides (CPs) isolated from Ecklonia cava enzymatic extracts using AMG, Viscozyme, Protamex, and Alcalase enzyme against a colon cancer cell line, CT26 cells. Among them, the CP of Protamex extract (PCP) contained the highest fucose and sulfated group contents and showed the highest growth inhibitory effect against CT-26 cells. In addition, PCP dose-dependently increased the formation of apoptotic body and the percentage of Sub-G1 DNA contents. Also, PCP activated caspase 9 and PARP as regulating the expressions of Bax and Bcl-2. Moreover, PPP2, a fraction purified from PCP showed the highest growth inhibitory effect against CT 26 cells with the increased fucose and sulfated group contents. The results demonstrate that the isolated SP containing plentiful fucose and sulfated group contents has the anticancer effect on colon cancer cells via regulation of Bcl-2/Bax signal pathway.

6,6'-Bieckol protects insulinoma cells against high glucose-induced glucotoxicity by reducing oxidative stress and apoptosis.

Pancreatic ß cells are highly sensitive to oxidative stress, which might play an important role in ß cell death in diabetes. The protective effect of 6,6'-bieckol, a phlorotannin polyphenol compound purified from Ecklonia cava, against high glucose-induced glucotoxicity was investigated in rat insulinoma cells. High glucose (30 mM) treatment induced the death of rat insulinoma cells, but treatment with 10 or 50 µg/mL 6,6'-bieckol significantly inhibited the high glucose-induced glucotoxicity. Furthermore, treatment with 6,6'-bieckol dose-dependently reduced the level of thiobarbituric acid reactive substances, generation of intracellular reactive oxygen species, and the level of nitric oxide, all of which were increased by high glucose concentration. In addition, 6,6'-bieckol protected rat insulinoma cells from apoptosis under high-glucose conditions. These effects were associated with increased expression of the anti-apoptotic protein Bcl-2 and reduced expression of the pro-apoptotic protein Bax. These findings indicate that 6,6'-bieckol could be used as a potential nutraceutical agent offering protection against the glucotoxicity caused by hyperglycemia-induced oxidative stress associated with diabetes.

Anti-Inflammatory Action of an Antimicrobial Model Peptide That Suppresses the TRIF-Dependent Signaling Pathway via Inhibition of Toll-Like Receptor 4 Endocytosis in Lipopolysaccharide-Stimulated Macrophages.

Antimicrobial peptides (AMPs), also called host defense peptides, particularly those with amphipathic helical structures, are emerging as target molecules for therapeutic development due to their immunomodulatory properties. Although the antimicrobial activity of AMPs is known to be exerted primarily by permeation of the bacterial membrane, the mechanism underlying its anti-inflammatory activity remains to be elucidated. We report potent anti-inflammatory activity of WALK11.3, an antimicrobial model peptide with an amphipathic helical conformation, in lipopolysaccharide (LPS)-stimulated RAW264.7 cells. This peptide inhibited the expression of inflammatory mediators, including nitric oxide, COX-2, IL-1ß, IL-6, INF-ß, and TNF-α. Although WALK11.3 did not exert a major effect on all downstream signaling in the MyD88-dependent pathway, toll-like receptor 4 (TLR4)- mediated pro-inflammatory signals were markedly attenuated in the TRIF-dependent pathway due to inhibition of the phosphorylation of STAT1 by attenuation of IRF3 phosphorylation. WALK11.3 specifically inhibited the endocytosis of TLR4, which is essential for triggering TRIF-mediated signaling in macrophage cells. Hence, we suggest that specific interference with TLR4 endocytosis could be one of the major modes of the anti-inflammatory action of AMPs. Our designed WALK11 peptides, which possess both antimicrobial and anti-inflammatory activities, may be promising molecules for the development of therapies for infectious inflammation.

First evidence that Ecklonia cava-derived dieckol attenuates MCF-7 human breast carcinoma cell migration.

We investigated the effect of Ecklonia cava (E. cava)-derived dieckol on movement behavior and the expression of migration-related genes in MCF-7 human breast cancer cell. Phlorotannins (e.g., dieckol, 6,6'-biecko, and 2,7″-phloroglucinol-6,6'-bieckol) were purified from E. cava by using centrifugal partition chromatography. Among the phlorotannins, we found that dieckol inhibited breast cancer cell the most and was selected for further study. Radius™-well was used to assess cell migration, and dieckol (1-100 µM) was found to suppress breast cancer cell movement. Metastasis-related gene expressions were evaluated by RT-PCR and Western blot analysis. In addition, dieckol inhibited the expression of migration-related genes such as matrix metalloproteinase (MMP)-9 and vascular endothelial growth factor (VEGF). On the other hand, it stimulated the expression of tissue inhibitor of metalloproteinase (TIMP)-1 and TIMP-2. These results suggest that dieckol exerts anti-breast cancer activity via the regulation of the expressions of metastasis-related genes, and this is the first report on the anti-breast cancer effect of dieckol.