A Shark Liver Gene-Derived Active Peptide Expressed in the Silkworm,Bombyx mori: Preliminary Studies for Oral Administration of the Recombinant Protein

Active peptide from shark liver (APSL) is a cytokine from Chiloscyllium plagiosum that can stimulate liver regeneration and protects the pancreas. To study the effect of orally administered recombinant APSL (rAPSL) on an animal model of type 2 diabetes mellitus, the APSL gene was cloned, and APSL was expressed in Bombyx mori N cells (BmN cells), silkworm larvae and silkworm pupae using the silkworm baculovirus expression vector system (BEVS). It was demonstrated that rAPSL was able to significantly reduce the blood glucose level in mice with type 2 diabetes induced by streptozotocin. The analysis of paraffin sections of mouse pancreatic tissues revealed that rAPSL could effectively protect mouse islets from streptozotocin-induced lesions. Compared with the powder prepared from normal silkworm pupae, the powder prepared from pupae expressing rAPSL exhibited greater protective effects, and these results suggest that rAPSL has potential uses as an oral drug for the treatment of diabetes mellitus in the future.     

茯砖茶改善2型糖尿病小鼠代谢紊乱的效果研究

为探究茯砖茶能否通过调节肠道微生物群改善2型糖尿病(T2DM)的代谢紊乱,建立T2DM小鼠模型,给予400 mg·kg-1茯砖茶水提取物灌胃干预,观测T2DM小鼠的饮食量、饮水量、空腹体重、空腹血糖、糖耐量等日常指标,血清中胰岛素(INS)、总胆汁酸(TBA)、总胆固醇(TC)、总甘油三酯(TG)、低密度脂蛋白(LDL...     

Interaction between Marine-Derived n-3 Long Chain Polyunsaturated Fatty Acids and Uric Acid on Glucose Metabolism and Risk of Type 2 Diabetes Mellitus: A Case-Control Study

The present case-control study explored the interaction between marine-derived n-3 long chain polyunsaturated fatty acids (n-3 LC PUFAs) and uric acid (UA) on glucose metabolism and risk of type 2 diabetes mellitus (T2DM). Two hundred and eleven healthy subjects in control group and 268 T2DM subjects in case group were included. Plasma phospholipid (PL) fatty acids and biochemical parameters were detected by standard methods. Plasma PL C22:6n-3 was significantly lower in case group than in control group, and was negatively correlated with fasting glucose (r = −0.177, p < 0.001). Higher plasma PL C22:6n-3 was associated with lower risk of T2DM, and the OR was 0.32 (95% confidence interval (CI), 0.12 to 0.80; p = 0.016) for per unit increase of C22:6n-3. UA was significantly lower in case group than in control group. UA was positively correlated with fasting glucose in healthy subjects, but this correlation became negative in T2DM subjects. A significant interaction was observed between C22:6n-3 and UA on fasting glucose (p for interaction = 0.005): the lowering effect of C22:6n-3 was only significant in subjects with a lower level of UA. In conclusion, C22:6n-3 interacts with UA to modulate glucose metabolism.     

壳聚糖复合β-乳球蛋白负载EGCG纳米粒的制备及其对糖尿病小鼠血糖的影响

表没食子儿茶素没食子酸酯（EGCG）作为茶叶中主要生物活性成分,具有良好的生理功能,但低稳定性使其容易被氧化降解,生物利用率低。利用羧甲基壳聚糖（CMC）、壳聚糖盐酸盐（CHC）、β-乳球蛋白（β-LG）作为壁材,制备壳聚糖复合β-乳球蛋白负载EGCG纳米粒,通过透射电镜、结构表征（粒径、Zeta电位测定）对颗粒微观形态进行观察,利用高效液相色谱仪对颗粒包埋率、模拟胃肠液释放率进行测定,最后建立糖尿病小鼠模型,探究包埋后颗粒的降血糖活性。结果表明,CS-β-LG-EGCG纳米粒结构完整、粒径10~100 nm、粒子分散;包埋率大于50%,且在肠液和胃液中具有缓释作用;CS-β-LG-EGCG纳米粒与胰岛素无拮抗作用,与未包埋的EGCG相比,包埋后颗粒具备的缓释作用可减缓血糖的回升。     

茶多酚防治2型糖尿病的分子机理研究进展

茶多酚作为天然功能性物质能有效防治2型糖尿病,但是其具体作用机制仍不太清楚。研究表明它的作用机理主要是通过调控糖代谢平衡：包括降低α-糖苷酶、α-淀粉酶等双糖酶活性,调控胰岛素信号传导途径及AMPK途径中多个分子靶点的磷酸化水平,影响酶与转录因子的活性与表达,减弱胰岛素抵抗及糖异生作用,促进胰岛素的合成与分泌,促进靶组织对葡萄糖的吸收与利用等;同时,茶多酚能够调控脂代谢,通过抑制脂质合成与积累的相关酶的活性及转录因子的表达,促进脂质的氧化代谢,减轻脂代谢紊乱;另外,茶多酚的抗氧化与抗炎作用可以有效减轻组织细胞的氧化伤害和炎症损伤,减少细胞凋亡。     

Polyphenol-Rich Fraction of Ecklonia cava Improves Nonalcoholic Fatty Liver Disease in High Fat Diet-Fed Mice

Ecklonia cava (E. cava; CA) is an edible brown alga with beneficial effects in diabetes via regulation of various metabolic processes such as lipogenesis, lipolysis, inflammation, and the antioxidant defense system in liver and adipose tissue. We investigated the effect of the polyphenol-rich fraction of E. cava produced from Gijang (G-CA) on nonalcoholic fatty liver disease (NAFLD) in high-fat diet (HFD)-fed mice. C57BL6 mice were fed a HFD for six weeks and then the HFD group was administered 300 mg/kg of G-CA extracts by oral intubation for 10 weeks. Body weight, fat mass, and serum biochemical parameters were reduced by G-CA extract treatment. MRI/MRS analysis showed that liver fat and liver volume in HFD-induced obese mice were reduced by G-CA extract treatment. Further, we analyzed hepatic gene expression related to inflammation and lipid metabolism. The mRNA expression levels of inflammatory cytokines and hepatic lipogenesis-related genes were decreased in G-CA-treated HFD mice. The mRNA expression levels of cholesterol 7 alpha-hydroxylase 1 (CYP7A1), the key enzyme in bile acid synthesis, were dramatically increased by G-CA treatment in HFD mice. We suggest that G-CA treatment ameliorated hepatic steatosis by inhibiting inflammation and improving lipid metabolism.     

Anticancer Activity of a Hexapeptide from Skate (Raja porosa) Cartilage Protein Hydrolysate in HeLa Cells

In this study, the hexapeptide Phe-Ile-Met-Gly-Pro-Tyr (FIMGPY), which has a molecular weight of 726.9 Da, was separated from skate (Raja porosa) cartilage protein hydrolysate using ultrafiltration and chromatographic methods, and its anticancer activity was evaluated in HeLa cells. Methylthiazolyldiphenyl-tetrazolium bromide (MTT) assay indicated that FIMGPY exhibited high, dose-dependent anti-proliferation activities in HeLa cells with an IC₅₀ of 4.81 mg/mL. Acridine orange/ethidium bromide (AO/EB) fluorescence staining and flow cytometry methods confirmed that FIMGPY could inhibit HeLa cell proliferation by inducing apoptosis. Western blot assay revealed that the Bax/Bcl-2 ratio and relative intensity of caspase-3 in HeLa cells treated with 7-mg/mL FIMGPY were 2.63 and 1.83, respectively, significantly higher than those of the blank control (p < 0.01). Thus, FIMGPY could induce apoptosis by upregulating the Bax/Bcl-2 ratio and caspase-3 activation. Using a DNA ladder method further confirmed that the anti-proliferation activity of FIMGPY was attributable to its role in inducing apoptosis. These results suggest that FIMGPY from skate cartilage protein hydrolysate may have applications as functional foods and nutraceuticals for the treatment and prevention of cancer.     

Effects of Halide Ions on the Carbamidocyclophane Biosynthesis in Nostoc sp. CAVN2

In this study, the influence of halide ions on [7.7]paracyclophane biosynthesis in the cyanobacterium Nostoc sp. CAVN2 was investigated. In contrast to KI and KF, supplementation of the culture medium with KCl or KBr resulted not only in an increase of growth but also in an up-regulation of carbamidocyclophane production. LC-MS analysis indicated the presence of chlorinated, brominated, but also non-halogenated derivatives. In addition to 22 known cylindrocyclophanes and carbamidocyclophanes, 27 putative congeners have been detected. Nine compounds, carbamidocyclophanes M−U, were isolated, and their structural elucidation by 1D and 2D NMR experiments in combination with HRMS and ECD analysis revealed that they are brominated analogues of chlorinated carbamidocyclophanes. Quantification of the carbamidocyclophanes showed that chloride is the preferably utilized halide, but incorporation is reduced in the presence of bromide. Evaluation of the antibacterial activity of 30 [7.7]paracyclophanes and related derivatives against selected pathogenic Gram-positive and Gram-negative bacteria exhibited remarkable effects especially against methicillin- and vancomycin-resistant staphylococci and Mycobacterium tuberculosis. For deeper insights into the mechanisms of biosynthesis, the carbamidocyclophane biosynthetic gene cluster in Nostoc sp. CAVN2 was studied. The gene putatively coding for the carbamoyltransferase has been identified. Based on bioinformatic analyses, a possible biosynthetic assembly is discussed.     

Dual Targeting of PTP1B and Aldose Reductase with Marine Drug Phosphoeleganin: A Promising Strategy for Treatment of Type 2 Diabetes

An in-depth study on the inhibitory mechanism on protein tyrosine phosphatase 1B (PTP1B) and aldose reductase (AR) enzymes, including analysis of the insulin signalling pathway, of phosphoeleganin, a marine-derived phosphorylated polyketide, was achieved. Phosphoeleganin was demonstrated to inhibit both enzymes, acting respectively as a pure non-competitive inhibitor of PTP1B and a mixed-type inhibitor of AR. In addition, in silico docking analyses to evaluate the interaction mode of phosphoeleganin with both enzymes were performed. Interestingly, this study showed that phosphoeleganin is the first example of a dual inhibitor polyketide extracted from a marine invertebrate, and it could be used as a versatile scaffold structure for the synthesis of new designed multiple ligands.     

Biological Properties of Fucoxanthin in Oil Recovered from Two Brown Seaweeds Using Supercritical CO2 Extraction

The bioactive materials in brown seaweeds hold great interest for developing new drugs and healthy foods. The oil content in brown seaweeds (Saccharina japonica and Sargassum horneri) was extracted by using environmentally friendly supercritical CO₂ (SC-CO₂) with ethanol as a co-solvent in a semi-batch flow extraction process and compared the results with a conventional extraction process using hexane, ethanol, and acetone mixed with methanol (1:1, v/v). The SC-CO₂ method was used at a temperature of 45 °C and pressure of 250 bar. The flow rate of CO₂ (27 g/min) was constant for the entire extraction period of 2 h. The obtained oil from the brown seaweeds was analyzed to determine their valuable compounds such as fatty acids, phenolic compounds, fucoxanthin and biological properties including antioxidant, antimicrobial, and antihypertension effects. The amounts of fucoxanthin extracted from the SC-CO₂ oils of S. japonica and S. horneri were 0.41 ± 0.05 and 0.77 ± 0.07 mg/g, respectively. High antihypertensive activity was detected when using mixed acetone and methanol, whereas the phenolic content and antioxidant property were higher in the oil extracted by SC-CO₂. The acetone–methanol mix extracts exhibited better antimicrobial activities than those obtained by other means. Thus, the SC-CO₂ extraction process appears to be a good method for obtaining valuable compounds from both brown seaweeds, and showed stronger biological activity than that obtained by the conventional extraction process.     

The Cytoprotective Effect of Petalonia binghamiae Methanol Extract against Oxidative Stress in C2C12 Myoblasts: Mediation by Upregulation of Heme Oxygenase-1 and Nuclear Factor-Erythroid 2 Related Factor 2

This study was designed to examine the protective effects of the marine brown algae Petalonia binghamiae against oxidative stress-induced cellular damage and to elucidate the underlying mechanisms. P. binghamiae methanol extract (PBME) prevented hydrogen peroxide (H₂O₂)-induced growth inhibition and exhibited scavenging activity against intracellular reactive oxygen species (ROS) induced by H₂O₂ in mouse-derived C2C12 myoblasts. PBME also significantly attenuated H₂O₂-induced comet tail formation in a comet assay, histone γH2A.X phosphorylation, and annexin V-positive cells, suggesting that PBME prevented H₂O₂-induced cellular DNA damage and apoptotic cell death. Furthermore, PBME increased the levels of heme oxygenase-1 (HO-1), a potent antioxidant enzyme, associated with the induction of nuclear factor-erythroid 2 related factor 2 (Nrf2). However, zinc protoporphyrin IX, a HO-1 competitive inhibitor, significantly abolished the protective effects of PBME on H₂O₂-induced ROS generation, growth inhibition, and apoptosis. Collectively, these results demonstrate that PBME augments the antioxidant defense capacity through activation of the Nrf2/HO-1 pathway.     

In vivo and in vitro anti-inflammatory activity of neorogioltriol, a new diterpene extracted from the red algae Laurencia glandulifera

Neorogioltriol is a tricyclic brominated diterpenoid isolated from the organic extract of the red algae Laurencia glandulifera. In the present study, the anti-inflammatory effects of neorogioltriol were evaluated both in vivo using carrageenan-induced paw edema and in vitro on lipopolysaccharide (LPS)-treated Raw264.7 macrophages. The in vivo study demonstrated that the administration of 1 mg/kg of neorogioltriol resulted in the significant reduction of carregeenan-induced rat edema. In vitro, our results show that neorogioltriol treatment decreased the luciferase activity in LPS-stimulated Raw264.7 cells, stably transfected with the NF-κB-dependent luciferase reporter. This effect on NF-κB activation is not mediated through MAPK pathways. The inhibition of NF-κB activity correlates with decreased levels of LPS-induced tumor necrosis factor-alpha (TNFα) present in neorogioltriol treated supernatant cell culture. Further analyses indicated that this product also significantly inhibited the release of nitric oxide and the expression of cyclooxygenase-2 (COX-2) in LPS-stimulated Raw264.7 cells. These latter effects could only be observed for neorogioltriol concentrations below 62.5 μM. To our knowledge, this is the first report describing a molecule derived from Laurencia glandulifera with anti-inflammatory activity both in vivo and in vitro. The effect demonstrated in vitro may be explained by the inhibition of the LPS-induced NF-κB activation and TNFα production. NO release and COX-2 expression may reinforce this effect.     

Antidiabetic and Antioxidant Effects of Polyphenols in Brown Alga <Emphasis Type="Italic">Ecklonia stolonifera</Emphasis> in Genetically Diabetic KK-A<Superscript>y</Superscript> Mice

The dietary intake and control of blood glucose levels are very important in hyperglycemic patients and α-glucosidase inhibitors are a cost-effective means to preventing the progression of diabetes. In search of a natural inhibitor from food materials, α-glucosidase inhibitory activity and the anti-hyperglycemic effects of a brown alga, Ecklonia stolonifera, were investigated using non-insulin dependent diabetic mice. Methanolic extract of E. stolonifera (MEE), which contains a high content of polyphenols, showed strong inhibition of α-glucosidase in vitro. Male KK-A^y mice, a genetically non-insulin dependent diabetic model, showed hyperglycemia with aging, but the ingestion of MEE suppressed the increase in plasma glucose and lipid peroxidation levels in unfasted KK-A^y mice dose dependently. In KK-A^y mice, which were fed the MEE diet for 4 weeks, MEE moderated the elevation of plasma glucose levels after the oral administration of maltose. The polyphenols in MEE were estimated to be phlorotannins by HPLC-PDA and LC/MS analyses. These results demonstrate that E. stolonifera, seaweed typically used as a health food, has strong antidiabetic and antioxidant effects in vivo, thus, it may have beneficial properties in the prevention of diabetes and could be useful in the development of an antidiabetic pharmaceutical and functional food.