Antihyperlipidemic effects of different molecular weight sulfated polysaccharides from Ulva pertusa (Chlorophyta).

Ulvan, a sulfated polysaccharide from Ulva pertusa, was degraded to yield two low molecular weight fractions U1 and U2. The molecular weights of ulvan and its fractions were determined and varied from 151.6 to 28.2 kDa. They were fed to rats on a hypercholesterolemic diet for 21 days to evaluate and compare the antihyperlipidemic actions. Ulvan-based diet significantly lowered the levels of serum total cholesterol (-45.2%, P<0.05) and low density lipoprotein cholesterol (LDL-cholesterol, -54.1%, P<0.05). While U1- and U2-based diets significantly elevated the levels of serum high density lipoprotein cholesterol (HDL-cholesterol, +22.0% for U1, not significant; +61.0% for U2; P<0.05) and reduced triglyceride (TG, -82.4% for U1, -77.7% for U2; P<0.05) in rats as compared to control diet. In addition, consumptions of various ulvans significantly increased fecal bile acid excrement. The results indicated that ulvans with different molecular weights exhibited diverse effects on lipid metabolism. The high molecular weight ulvan was effective in serum total and LDL-cholesterol, whereas low molecular weight fractions were in TG and HDL-cholesterol. The fractions were considered to be more beneficial to hyperlipidemia associated with diabetes over ulvan.     

HPLC法比较2种银杏外种皮多糖的相对分子质量及含量

目的:采用HPLC法比较2种银杏外种皮多糖的相对分子质量及含量.方法:从银杏外种皮中提取出多糖,分别于常温下贮藏5年和3年后测定并比较其相对分子质量和含量.以右旋糖酐为标样,采用HPLC法,PL aquagel-OH MIXED(300mm×7.5 mm,8 μm)色谱柱,柱温25℃,示差折光检测器,流动相为超纯水,流速1.0 mL·min-1.结果:贮藏5年和3年的2种银杏外种皮多糖的平均相对分子质量分别为10 825.3(RSD=0.45%)和11 062.5(RSD=0.78%);其多糖含量分别为66.8%(RSD=5.9%)和68.7%(RSD=3.4%).结论:在常温下,银杏外种皮多糖随着贮藏时间的延长,其相对分子质量和含量会发生变化.     

A comparison study between different molecular weight polysaccharides derived from Lentinus edodes and their antioxidant activities in vivo

Context: Polysaccharide purified Lentinus edodes (Berk.) Sing (Tricholomataceae) has been reported to attenuate oxidative stress in vitro.

Objective: This study investigated whether polysaccharides from L. edodes with different molecular weight have protective effects against oxidative stress induced by d-galactose (d-gal) in vivo, and determined the specific relationship between molecular weight and antioxidant activity.

Materials and methods: In the present study, we successfully obtained three purified polysaccharides, coded as LT1, LT2, and LT3, and their molecular weights were 25.5, 306.2, and 605.4?kDa, respectively. The d-gal-treated mice received three polysaccharides once daily for 60 days. The activities of superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px), the content of malondialdehyde (MDA), and erythrocyte membrane fluidity were measured to evaluate the changes of the antioxidant ability.

Results: It was demonstrated that the administration of LT1, LT2, and LT3 could improve the antioxidant status to different levels. Furthermore, LT2 exhibited the highest antioxidant ability among these samples in vivo. Indeed, LT2 significantly decreased the content of MDA in liver (15.91?±?0.31 versus 23.79?±?1.18 nmol/mg protein for the model group, p?<?0.05), enhanced the fluidity of erythrocyte membrane (2.458?±?0.023 versus 2.167?±?0.024 for the model group, p?<?0.05), and increased the activities of SOD (147.19?±?4.90 versus 82.26?±?5.55 units/mg protein for the model group, p?<?0.05) and GSH-Px (310.91?±?6.24 versus 243.64?±?6.77 units/mg protein for the model group, p?<?0.05) in liver.

Discussion and conclusion: The LT2 had a potential to be used as a novel natural antioxidant.     

不同分子质量当归多糖对大鼠正常肝细胞内hepcidin表达的影响

目的:研究不同分子质量当归多糖(ASP1、ASP2)对大鼠正常肝细胞hepcidin表达的直接抑制作用。方法:采用改良的原位在体两步灌流法分离出原代大鼠肝细胞;以2 IU.mL-1的重组人促红细胞生成素(rhEPO)作为阳性对照,实验组中2种分子质量当归多糖分别分为高、中、低剂量,在此基础上根据细胞培养时间的不同再进一步分组;ELISA检测细胞上清中hepcidin的累积分泌量。结果:rhEPO作用24 h后,肝细胞hepcidin的累积分泌量下降52.6%;大分子质量ASP1对hepcidin表达无明显影响;而小分子质量ASP2在连续作用48 h后产生显著的hepcidin抑制效应,且抑制强度呈剂量相关性。结论:当归多糖中的大分子质量段在体外不能直接影响大鼠正常肝细胞内hepcidin的表达含量,而小分子质量段可以直接作用于肝细胞抑制hepcidin表达。     

In vivo antitumor and immunomodulation activities of different molecular weight lambda-carrageenans from Chondrus ocellatus.

lambda-Carrageenan is a sulfated galactan isolated from some red algae and have been reported to have many kinds of biological activities. lambda-Carrageenan from Chondrus ocellatus, an important economic alga in China and many other parts of the world, was degraded by microwave, and obtained five products that have different molecular weight: 650, 240, 140, 15, 9.3 kDa. Analytical results confirmed that microwave degradation might not change the chemical components and structure of polysaccharides under certain condition. In this study, tumor-inhibiting activities, weight of immune organ, nature killer cells activity, lymphocyte proliferation ratio and pathological slice of spleen and tumor cells from the control group and lambda-carrageenan-treated mice of transplanted S180 and H22 tumor were investigated. The results indicated that the five lambda-carrageenan samples all showed antitumor and immunomodulation activities in different degree. Molecular weight of polysaccharides had notable effect on the activities. In addition, their antitumor and immunomodulation have some relevance and the five lambda-carrageenans probably inhibited tumor by means of activating the immunocompetence of the body. Among all the experiment results, samples with the highest activities are PC4 and PC5 whose molecular weight are 15 and 9.3 kDa.     

不同相对分子质量聚乙二醇对槲皮素的增溶作用

目的　研究不同相对分子质量聚乙二醇对槲皮素的增溶作用。方法　分别用聚乙二醇 4 0 0 0 ,6 0 0 0 ,10 0 0 0 (PEG40 0 0 ,PEG60 0 0 ,PEG10 0 0 0 )为载体 ,采用熔融法制备槲皮素固体分散体 ,测定槲皮素原料药、固体分散物以及机械混合物的溶解度 ,以红外光谱和紫外光谱分析固体分散物。结果　槲皮素固体分散物中槲皮素的溶解度 (48.78,78.39,81.35 mg.L-1)比槲皮素 (12 .75 mg.L-1)以及相同质量比机械混合物 (12 .86 ,13.15 ,13.2 8mg.L-1)的溶解度有明显提高。结论　不同相对分子量聚乙二醇可以不同程度增加槲皮素的溶解度。     

A method for direct preparation of chitosan with low molecular weight from fungi.

By modifying the common method for the preparation of chitosan from fungi, low molecular weight chitosan with an average MW of 4.5 x 10(4) g/mol and a numerical MW of 1.7 x 10(4) g/mol can be directly extracted from the raw material without the need of thermal or chemical depolymerization. Based on the solubility of low molecular chitosan up to alkaline pH ranges, reprecipitation and washing with ethanol is required to keep the low molecular fraction within the preparation. The use of water for washing between the preparation steps would cause solving and discarding of the low molecular chitosan. The chitosan was analyzed by laser light scattering and 1H-NMR spectroscopy.     

Interaction of indomethacin with low molecular weight chitosan,and improvements of some pharmaceutical properties of indomethacin by low molecular weight chitosans

The interaction of four kinds of low molecular weight chitosans, which were different in molecular weight and degree of deacetylation, were studied in solution and the solid state using an anti-inflammatory drug, indomethacin (IM), as an acidic model molecule. The solubility of IM enhanced with increasing concentration of low molecular weight chitosan, especially C-I which had the lowest molecular weight and least degree of deacetylation. The C-I crystal complex was obtained in a molar ratio of 16:1 (IM: C-I) from aqueous solution. The data suggested that the acetyl group and amino group of chitosan played an important role in the complexation. The IM dissolution rates from kneaded mixtures with low molecular weight chitosans were enhanced in the order of C-I >C-II >C-III >C-IV (molecular weight: C-IV >C-III >C-II >C-I). The oral absorption rate of IM from C-I kneaded mixture was improved compared with IM alone.     

Bystander effects of cancer cell lines transduced with the multisubstrate deoxyribonucleoside kinase of Drosophila melanogaster and synergistic enhancement by hydroxyurea.

The multisubstrate deoxyribonucleoside kinase of Drosophila melanogaster (Dm-dNK) can be expressed in human cells with retained enzymatic activity. The cells expressing Dm-dNK exhibit increased sensitivity to several cytotoxic nucleoside analogs. In this study, we further evaluated Dm-dNK as a potential novel suicide gene in combination with (E)-5-(2-bromovinyl)-2'-deoxyuridine (BVDU) as the prodrug. We used two human cancer cell lines transduced with a retrovirus encoding the Dm-dNK cDNA and investigated whether the cells expressing the enzyme can induce cell death of untransduced cells, a phenomenon known as the "bystander effect". A bystander effect was observed in a thymidine kinase-deficient human osteosarcoma cell line but not in the MIA PaCa-2 human pancreatic adenocarcinoma cell line. The cytotoxicity of BVDU increased in both cell lines when the compound was used in combination with subtoxic concentrations of hydroxyurea. Hydroxyurea also enhanced the bystander effect in the osteosarcoma cells, but not in the MIA PaCa-2 cells, treated with BVDU. These findings indicate that BVDU phosphorylated by Dm-dNK in transduced cancer cells may also induce bystander cell death in certain cell lines.     

不同材质及孔径超滤膜对麦冬皂苷类成分的影响

目的 考查不同材质及不同孔径的超滤膜对5种麦冬皂苷类成分的影响。方法 以麦冬皂苷C、麦冬皂苷D、麦冬皂苷D''、麦冬皂苷Ra、龙血苷F为考察指标,利用HPLC-UV法测定其超滤前后变化,考察不同材质及孔径的超滤膜对5种麦冬皂苷收率的影响以及各超滤阶段对麦冬皂苷类成分截留率的变化情况。结果 不同材质及不同孔径的超滤膜处理下,麦冬皂苷类成分的收率不同;聚醚砜材质超滤膜对各超滤阶段的麦冬皂苷类成分截留率变化趋势与纤维素材质是一致的。结论 采用100 kDa的聚醚砜超滤膜,可以使麦冬皂苷类成分的收率达到最高,用50%乙醇进行等体积透析,会对麦冬皂苷的收率有较大的改善。     

Differential effects of saccharin supplementation on alcohol and water consumption by Wistar rats from different sources

The study was aimed to elucidate whether the dissimilar effects of concurrent presentation of sweet water on alcohol consumption previously reported for Wistar rats from different sources remain unchanged when alcohol is also flavored with 0.1% saccharin. Male Wistar rats from Laboratory of Experimental Biological Models (LEBM) and Krukovo animal farm (K) stocks having had 2 months free access to food, tap water, and 10% alcohol were given four consecutive two-bottle drinking tests: alcohol versus water, alcohol versus sweet water, sweet alcohol versus water, or sweet alcohol versus sweet water. The test order was quasi-random and each test lasted 4 days. In Wistar (K) rats, flavoring of either water or alcohol solution increased consumption of each of the fluids and decreased intake of concurrently available fluids. The elevation in water intake induced by its sweetening was antagonized by flavoring of alcohol solution. In Wistar (LEBM) rats, flavoring of either water or alcohol increased consumption of each of the fluid, but did not change the intake of alternative fluids. The stable alcohol consumption by Wistar (LEBM) rats and its suppression seen in Wistar (K) rats induced by concurrent presentation of flavored water parallel the patterns previously observed among P, sP, and HAD rats suggesting the existence among alcohol-consuming animals of typological diversity of alcohol motivation.     

Risks of premature death and cancer predicted by body weight in early adult life.

In a study of 30 months duration, involving 600 male and 600 female Wistar rats fed on 12 different diets/dietary regimes, none of which involved deliberate exposure to any known genotoxic carcinogen, highly significant between-group differences were observed in survival and incidence of various neoplastic and non-neoplastic diseases. A full report of the findings is being prepared. Here we report that, irrespective of diet or dietary regime, there were highly significant correlations of body weight at 29 weeks of age with premature death (P less than 0.0001 in both males and females), with development of benign or malignant neoplasm of any site (P less than 0.0001 in males and P less than 0.01 in females) and with development of malignant neoplasm at any site (P less than 0.0001 for sexes combined). Numerous kinds of neoplasm contributed to these overall correlations. The most significant were pituitary tumour (P less than 0.0001), mammary gland tumour (P less than 0.0001), squamous or anaplastic carcinoma of the jaw (P less than 0.001), and subcutaneous mesodermal tumours (P less than 0.05). The 20% of rats that were heaviest at 29 weeks were more than twice as likely to die prematurely than the lightest 20% (2.56 times--males, and 2.11 times--females), and almost twice as likely to develop a malignant tumour (1.87 times for the sexes combined). These findings have important implications for the design and interpretation of carcinogenicity tests in rodents and of laboratory and human studies of relationships between diet, ageing-related degenerative diseases, and cancer.     

S100B serum levels and long-term improvement of negative symptoms in patients with schizophrenia.

S100B, a calcium-binding protein produced by astroglial cells, mediates paracrine and autocrine effects on neurons and glial cells. It regulates the balance between proliferation and differentiation in neurons and glial cells by affecting protective and apoptotic mechanisms. Post-mortem studies have demonstrated a deficit in synapses and dendrites in brains of schizophrenics. Recent studies have shown increased S100B levels in medicated acutely psychotic schizophrenic patients as well as unmedicated or drug naive schizophrenics. One study reported a positive correlation between negative symptoms and S100B. S100B serum levels (quantitative immunoassay) and psychopathology (Positive and Negative Syndrome Scale, PANSS) were examined upon study admission and after 12 and 24 weeks of standardized treatment in 98 chronic schizophrenic patients with primarily negative symptoms. Compared to age- and sex-matched healthy controls, the schizophrenic patients showed significantly increased S100B concentrations upon admission and after 12 and 24 weeks of treatment. High PANSS negative scores were correlated with high S100B levels. Regression analysis comparing psychopathology subscales and S100B identified negative symptomatology as the predicting factor for S100B. S100B is not just elevated during acute stages of disease since it remains elevated for at least 6 months following an acute exacerbation. With regard to psychopathology, negative symptomatology appears to be the predicting factor for the absolute S100B concentration. This might indicate that S100B in schizophrenic patients either promotes apoptotic mechanisms by itself or is released from astrocytes as part of an attempt to repair a degenerative or destructive process.     

A low molecular weight component derived from the milk of hyperimmunised cows suppresses inflammation by inhibiting neutrophil emigration.

An earlier study demonstrated that hyperimmunisation of dairy cows with a polyvalent bacterial vaccine stimulated the secretion of a small molecular weight anti-inflammatory moiety in the milk. This hyperimmune milk factor (HIMF) has been further investigated in the present experiments. HIMF was found to suppress the cellular phase of the response to carrageenin and also the neutrophil-dependent reverse passive Arthus reaction. These results, together with the observation that the administration of HIMF led to an increase in the number of circulating neutrophils, suggested that the agent might inhibit inflammation by interfering with the ability of neutrophils to emigrate from the vasculature. In vivo studies carried out to evaluate this possibility demonstrated that HIMF suppressed neutrophil emigration by up to 75%. In vitro experiments established that the ability of neutrophils to respond to chemotactic stimuli or adhere to endothelial cells was not affected by HIMF. It is possible, therefore, that the agent modulates inflammation by down-regulating the synthesis of inducible pro-inflammatory cytokines or adhesion molecules. Attempts are presently being made to isolate the active moiety to allow the activity of the agent at the molecular level to be studied in more detail.     

Stability of high molecular weight anticancer agent SMANCS and its transfer from oil-phase to water-phase. Comparative study with neocarzinostatin

SMANCS is a conjugate protein of copolymer of styrene-maleic acid [SMA] (molecular weight: 1,500) and an antitumor protein neocarzinostatin [NCS] (molecular weight: 11,700). It has an approximate molecular weight of 15,000. We report here stability of SMANCS in oil and in water, and NCS in water, under various physical conditions such as exposure to heat, UV, pH, and ultrasonic treatment. Then, we carried out an experiment of transfer of SMANCS in lipid contrast medium [lipiodol] (oil phase) to water phase (blood and physiological saline) in vitro. Results are summarized as follows: In aqueous condition, SMANCS is far more stable than NCS against the exposure to heat and UV, though it is inactivated by excessive exposures. SMANCS in an oily medium was found much more stable even at higher temperatures than in the aqueous phase. Both SMANCS and NCS are the most stable at pH 4.9-6.0. SMANCS dissolved in oil transferred to water phase slowly, having T1/10 of 24 hours (in case of lipiodol). This helps maintaining the anticancer effect of the drug in vivo for a long period of time. SMANCS in lipiodol was found to exert its action against cultured tumor cells as in an aqueous solution.