雪松松针多糖超声波酶法提取及其抗氧化性

为优化雪松松针多糖超声波酶法的提取工艺,并研究多糖结构及其抗氧化性。通过响应面法分析确定最佳提取参数为:3. 0 g松针粉末,液料比20∶1(m L∶g),提取温度80℃,超声功率560 W,超声时间47 min,纤维素酶用量12 FPU/g原料,提取两次,多糖得率高达10. 39%。采用高效液相色谱、红外光谱和核磁共振光谱等对松针多糖进行了结构表征,松针多糖以β-糖苷键为主要连接方式,并由葡萄糖、果糖、阿拉伯糖和半乳糖等单糖组成。体外抗氧化性研究结果表明:松针粗多糖对羟基自由基(·OH)和1,1-二苯基-2-三硝基苯肼自由基(DPPH·)的清除能力远高于纯化多糖,呈现出良好的量效关系,粗多糖对·OH和DPPH·的半抑制浓度IC50分别为0. 47 g/L和0. 076 g/L。     

Antioxidant activities of polysaccharides from Lentinus edodes and their significance for disease prevention

The crude polysaccharide (LEP) was extracted by hot water from the fruiting bodies of Lentinus edodes, and further purified by DEAE-cellulose and Sepharose CL-6B chromatography, giving three polysaccharide fractions coded as LEPA1, LEPB1 and LEPC1. In this study, their chemical and physical characteristics of polysaccharide fractions and antioxidant capacities, including scavenging activity against hydroxyl radicals, superoxide radicals and Fe²⁺-chelating ability, were valuated. The results showed that LEPC1 exhibited significantly antioxidant activity at a concentration-dependent manner. Therefore these results indicated that the water-extractable polysaccharide fraction was a potent antioxidant and could be developed to be new health medicine for fighting against various human diseases.     

翅果油树叶片中总生物碱抗氧化活性研究

采用80%乙醇浸提翅果油树叶片中总生物碱,硅胶柱层析纯化,并用碘量法测定翅果油树叶片中总生物碱对猪油抗氧化性能的影响,用番红花红O-Mn2 -H2O2光度法测定其对羟基自由基的清除效果,用NBT光还原法测定其对超氧阴离子的清除效果.结果表明:翅果油树叶片总生物碱可有效延缓猪油的脂质过氧化反应,对猪油氧化的抑制效果显著高于同浓度的维生素C;其具有较强的清除羟基自由基和超氧阴离子的能力,EC50值分别为0.236g/L和0.101g/L,当浓度为1g/L时,其对羟基自由基和超氧阴离子的清除率可达96.04%和90.05%,显著高于同浓度的维生素C.     

Characterization and antioxidant activity of Ginkgo biloba exocarp polysaccharides

Ginkgo biloba exocarp polysaccharide (GBEP) was obtained by hot water extraction, the crude polysaccharide was deproteinized by Sevag method and fractionized by a DEAE Sepharose fast flow anion-exchange column. Five fragments were obtained, including neutral polysaccharide (GBEP-N) and four acidic polysaccharides (GBEP-A1, GBEP-A2, GBEP-A3 and GBEP-A4). GBEP-N and GBEP-A3 were further purified by Superdex 200 gel column chromatography. The resulted two fractions GBEP-NN, and GBEP-AA were characterized by FT-IR, and HPGFC (high pressure gel filtration chromatography). Monosaccharide composition was determined by RP-HPLC method of precolumn derivatization with 1-phenyl-3-5-pyrazolone. GBEP-NN was mainly composed of rhamnose, arabinose, mannose, glucose and galactose, while GBEP-AA was mainly made up of mannose, rhamnose, glucuronic acid, galacturonic acid, galactosamine, glucose, galactose, xylose, arabinose, and fucose. The crude GBEP exhibited certain antioxidant activity. At the concentration of 5 mg/mL, the hydroxyl radical scavenging effect of GBEP was 90.52%, greater than 77.37% for the positive control ascorbic acid.     

Antioxidant properties of catechins and proanthocyanidins: Effect of polymerisation, galloylation and glycosylation

A range of catechins and oligomeric procyanidins was purified by high performance liquid chromatography (HPLC) from grape seed, apple skin, lentil and almond flesh. Catechins, galloylated epicatechin, glycosylated catechin, procyanidin dimers, galloylated dimers, trimer, and tetramer species were all identified, purified and quantified by HPLC, LC-MS and NMR. The antioxidant properties of these compounds were assessed using two methods: (a) inhibition of ascorbate/iron-induced peroxidation of phosphatidylcholine liposomes; (b) scavenging of the radical cation of 2,2'-azinobis(3-ethyl-benzothiazoline-6-sulphonate) (ABTS) relative to the water-soluble vitamin E analogue Trolox C (expressed as Trolox C equivalent antioxidant capacity, TEAC). Antioxidant activity in the lipid phase decreased with polymerisation in contrast with antioxidant action in the aqueous phase which increased from monomer to trimer and then decreased from trimer to tetramer. Galloylation of catechin and dimeric procyanidins decreased lipid phase and increased aqueous phase antioxidant activity. Glycosylation of catechin demonstrated decreased activity in both phases.     

Antioxidant properties of catechins and proanthocyanidins: Effect of polymerisation,galloylation and glycosylation

A range of catechins and oligomeric procyanidins was purified by high performance liquid chromatography (HPLC) from grape seed, apple skin, lentil and almond flesh. Catechins, galloylated epicatechin, glycosylated catechin, procyanidin dimers, galloylated dimers, trimer, and tetramer species were all identified, purified and quantified by HPLC, LC-MS and NMR. The antioxidant properties of these compounds were assessed using two methods: (a) inhibition of ascorbate/iron-induced peroxidation of phosphatidylcholine liposomes; (b) scavenging of the radical cation of 2,2′-azinobis(3-ethyl-benzothiazoline-6-sulphonate) (ABTS) relative to the water-soluble vitamin E analogue Trolox C (expressed as Trolox C equivalent antioxidant capacity, TEAC). Antioxidant activity in the lipid phase decreased with polymerisation in contrast with antioxidant action in the aqueous phase which increased from monomer to trimer and then decreased from trimer to tetramer. Galloylation of catechin and dimeric procyanidins decreased lipid phase and increased aqueous phase antioxidant activity. Glycosylation of catechin demonstrated decreased activity in both phases.     

Identification of structure and antioxidant activity of a fraction of polysaccharide purified from Dioscorea nipponica Makino

A large number of polysaccharides are present in boiling-water extraction of Dioscorea nipponica Makino. A DEAE-Sepharose CL-6B column chromatography was used to isolate the major polysaccharides from D. nipponica Makino. The largest amount of fraction of polysaccharide was subjected to further purification by gel-filtration on Sephadex G-100. The purified fraction was a neutral polysaccharide and a single peak in HPLC with Sugar KS-804 column, with a molecular weight of 38,000, and comprised mainly of glucose and fructose (45:1). Analysis by Periodate oxidation–Smith degradation indicated that there were 5.9%(1→)-glycosidic linkages, 4.94% (1 → 2)-glycosidic linkages, 61.16% (1 → 4)-glycosidic linkages, and 28% (1 → 3)-glycosidic linkages. On the basis of superoxide radical assay, hydroxyl radical assay, and self-oxidation of 1,2,3-phentriol assay, its antioxidant activity was investigated. This purified fraction of polysaccharide exhibited equivalent inhibiting power for self-oxidation of 1,2,3-phentriol to Vc, a little higher scavenging activity of superoxide radical and hydroxyl radical than Vc, and should be explored as a novel potential antioxidant.     

Purification and Characterization of Antioxidant Peptides from Leukocyte Extract of Crocodylus siamensis

Antioxidant peptides were isolated from the leukocyte extract of the Siamese crocodile, Crocodylus siamensis. Crocodile leukocyte was extracted by a combination of methods including freeze-thawing, acetic acid extraction and homogenization. The peptides in the leukocyte extract were purified by anion exchange chromatography and reversed phase-high performance liquid chromatography. The 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging assay was used to evaluate the antioxidant activity of the elution peaks at each purification step. As a result, there were two purified peptides exhibiting strong antioxidant activity in reducing free radicals on DPPH molecules. The amino acid sequences of these peptides were determined by LC-MS/MS as TDVLGLPAK (912.5 Da) and DPNAALPAGPR (1,148.6 Da), and their IC₅₀ values were 153.4 and 95.7 μM, respectively. The results of this study therefore indicate that leukocyte extract of C. siamensis contains peptides with antioxidant activity which could be used as a novel antioxidant.     

Isolation of a coaggregation-inhibiting cell wall polysaccharide from Streptococcus sanguis H1.

Coaggregation between Streptococcus sanguis H1 and Capnocytophaga ochracea ATCC 33596 cells is mediated by a carbohydrate receptor on the former and an adhesin on the latter. Two methods were used to release the carbohydrate receptor from the gram-positive streptococcus, autoclaving and mutanolysin treatment. The polysaccharide released from the streptococcal cell wall by either treatment was purified by ion-exchange chromatography; this polysaccharide inhibited coaggregation when preincubated with the gram-negative capnocytophaga partner. After hydrolysis of the polysaccharide by hydrofluoric acid (HF), the major oligosaccharide of the polysaccharide was purified by high-performance liquid chromatography. By analysis of the HF hydrolysis of the polysaccharide and the purified oligosaccharide, this major oligosaccharide appeared to be the repeating unit of the polysaccharide, with minor components resulting from internal hydrolysis of the major oligosaccharide. Gas chromatography results showed that the oligomer was a hexasaccharide, consisting of rhamnose, galactose, and glucose, in the ratio of 2:3:1, respectively. By weight, the purified hexasaccharide was a fourfold-more-potent inhibitor of coaggregation than the native polysaccharide. Resistance to hydrolysis by sulfuric acid alone and susceptibility to hydrolysis by HF suggested that oligosaccharide chains of the polysaccharide are linked by phosphodiester bonds. Studies with a coaggregation-defective mutant of S. sanguis H1 revealed that the cell walls of the mutant contained neither the polysaccharide nor the hexasaccharide repeating unit. The purification of both a polysaccharide and its constituent hexasaccharide repeating unit, which both inhibited coaggregation, and the absence of this polysaccharide or hexasaccharide on a coaggregation-defective mutant strongly suggest that the hexasaccharide derived from the polysaccharide functions as the receptor for the adhesin from C. ochracea ATCC 33596.     

Isolation and antioxidant property of the extracellular polysaccharide from <Emphasis Type="Italic">Rhodella reticulata</Emphasis>

The extracellular polysaccharide from Rhodella reticulata was separated from the culture medium followed by concentration and ethanol precipitation, and purified by anion exchange chromatography on DEAE-Sepharose Fast Flow. This study compared the free radical-scavenging property and antioxidant activity with various treatments of crude extracellular polysaccharides of R. reticulata. The results showed that both the crude extracellular polysaccharide and deproteinized crude extracellular polysaccharide gave evidence of the free radical scavenging and antioxidant activity in a dose-dependent manner. The crude extracellular polysaccharide exhibited higher free radical scavenging capacity and better antioxidant activity than the various treatments of crude extracellular polysaccharide samples. The superoxide anion radical scavenging ability of various samples was significantly higher compared to standard antioxidant (α-tocopherol). These results indicate that the extracellular polysaccharide of R. reticulata is a potent natural antioxidant.     

Purification and characterization of a novel polysaccharide involved in the pellicle produced by a thermotolerant Acetobacter strain

Acetobacter strains able to produce a thick pellicle at 37 degrees C were screened among many thermotolerant strains isolated from fruits in Thailand. As a result, Acetobacter sp. SKU 1100 was selected as the producer of a relatively thick pellicle even when cultured at higher temperatures such as 37 degrees C or 40 degrees C. This strain could produce a pellicle polysaccharide in a shaking submerged culture as well as under static culture conditions. The polysaccharide was found to be attached to the bacterial cells. Although the polysaccharide production was higher at 30 degrees C than at 37 degrees C in shaking submerged culture, the productivity in static culture was not decreased even at higher temperatures. The membrane-attached polysaccharide was purified from the SKU 1100 strain by cell disruptions using either ultrasonic treatment or lysozyme treatment, followed by ultracentrifugation, enzyme treatments, dialysis against SDS, DEAE-cellulose column chromatography, alcohol precipitation, and gel filtration chromatography. The polysaccharide purified by the sonic treatment and also by the mild conditions using lysozyme treatment had the same average molecular mass of 120 kDa. The purified polysaccharide was composed of three different monosaccharides; glucose, galactose, and rhamnose, in an approximately equimolar ratio of 1:1:1.     

Structure and protective effect of exopolysaccharide from P. Agglomerans strain KFS-9 against UV radiation

The water-soluble exopolysaccharide (WSEPS) from Pantoea agglomerans strain KFS-9 isolated from mangrove forest was prepared by removing bacterial cell from the fermentation liquid following by concentration and cold ethanol precipitation of the supernatant. The polysaccharide material was purified by gel permeation chromatography on a Sephacryl S-300HR column and characterized using chemical and spectral methods. The results show that WSEPS is protein-bound polysaccharide, and it is composed of arabinose, glucose galactose and gulcuronic acid in the molar ratio of 1.0:2.2:2.8:0.9. Their antioxidant activities in vitro were studied by various antioxidant assays, including hydroxyl radical scavenging, superoxide radical scavenging and antilipid peroxidation. The results show that the WSEPS extracted had a high antioxidant activity in a concentration-dependent manner (except the activity of antilipid peroxidation). WSEPS quenched hydroxyl radicals, superoxide radicals at low amounts, the IC(50) of which were 0.07 and 0.15 mg/ml, respectively. These results indicate that the protective effect of WSEPS against UV radiation is most likely to be due to the free radicals-scavenging ability.     

黄精多糖组成及其抗氧化活性分析

分离纯化湖南新化产黄精多糖,并对其组分、结构特征和抗氧化活性进行研究。本研究采用碱提法、Sevag法脱蛋白得水溶性粗多糖(PSP),并经DEAE-52和Sepharose CL-6B色谱柱分离纯化得黄精多糖分级组分。通过紫外、红外光谱和GC-MS进行初步结构分析,并检测其体内外抗氧化能力。结果 PSP经纯化得1个组分PSP-1a,不含蛋白质和核酸,具有典型多糖吸收峰,主要由半乳糖、阿拉伯糖、鼠李糖、木糖、葡萄糖组成,其摩尔百分含量分别为0.18%、1.50%、97.25%、0.77%和0.3%。体外抗氧化活性研究表明:PSP和PSP-1a均具有一定抗氧化性能力,且随浓度(1~10 mg/L)增大而增强,PSP-1a的抗氧化能力优于PSP,但弱于VC。体内实验显示,PSP-1a改善了高脂膳食肥胖小鼠结肠匀浆组织的氧化应激状况。     

Extraction and radicals scavenging activity of polysaccharides with microwave extraction from mung bean hulls

Extraction variables of microwave extraction mung polysaccharides (MEMPs) from mung bean hulls were optimized by Box-Behnken design. The optimal extraction parameter of MEMP was 700W, 70s and 17mL/g, and highest recovery was 60.03±2.56mgGE/gDW, which was agreed closely with predicted values. Two purified polysaccharide fractions (MEMP-1 and MEMP-2) were successfully isolated through DEAE cellulose-52 chromatography and Sephadex G-100 size-exclusion chromatography in steps. MEMP-1 was mainly composed of mannose and galactose while that of MEMP-2 was rhamnose and galactose. MEMP and purified fractions both had great radicals scavenging activities of hydroxyl and 1,1-diphenyl-2-picrylhydrazyl (DPPH) radicals, and MEMP-2 possessed highest antioxidant activity. The results suggested that MEMP-2 could be the suitable natural antioxidants and may be the functional foods for humans.     

Composition analysis and antioxidant activity of polysaccharide from Dendrobium denneanum

Three polysaccharide fractions (DDP1-1, DDP2-1 and DDP3-1) were successfully purified from the crude polysaccharide of Dendrobium denneanum by DEAE-Cellulose and Sephadex G-200 column chromatography. The average molecular weights (Mws) of these fractions were 51.5, 26.1 and 6.95 kDa, respectively. Monosaccharide components analysis indicated that DDP1-1 and DDP2-1 were composed of arabinose, xylose, mannose, glucose and galactose in a molar ratio of 1.00:2.82:57.11:140.82:7.76 and 1.00:1.62:1.18:77.5:7.79. DDP3-1 was composed of arabinose, mannose, glucose and galactose in a molar ratio of 1.00:1.03:8.84:2.00. On the basis of antioxidant test in vitro, DDP2-1 exhibited the highest antioxidant ability among these samples.     

Identification of polysaccharides from pericarp tissues of litchi (Litchi chinensis Sonn.) fruit in relation to their antioxidant activities

A large number of polysaccharides are present in the pericarp tissues of harvested litchi fruits. A DEAE Sepharose fast-flow anion-exchange column and a Sephadex G-50 gel-permeation column were used to isolate and purify the major polysaccharides from litchi fruit pericarp tissues. Antioxidant activities of these major polysaccharide components were also evaluated. An aqueous extract of the polysaccharides from litchi fruit pericarp tissues was chromatographed on a DEAE anion-exchange column to yield two fractions. The largest amount of the polysaccharide fraction was subjected to further purification by gel filtration on Sephadex G-50. The purified product was a neutral polysaccharide, with a molecular weight of 14 kDa, comprised mainly of 65.6% mannose, 33.0% galactose and 1.4% arabinose. Analysis by Smith degradation indicated that there were 8.7% of (1-->2)-glycosidic linkages, 83.3% of (1-->3)-glycosidic linkages and 8.0% of (1-->6)-glycosidic linkages in the polysaccharide. Furthermore, different polysaccharide fractions extracted and purified from litchi fruit pericarp tissues exhibited strong antioxidant activities. Among these fractions, the purified polysaccharide had the highest antioxidant activity and should be explored as a novel potential antioxidant.     

奶油栓孔菌菌丝体多糖的提取工艺优化、结构表征及抗氧化活性

奶油栓孔菌Trametes lactinea是一种生物活性丰富的大型真菌。本研究在单因素试验的基础上,通过响应面法优化其菌丝体多糖的提取工艺,利用DEAE-Cellulose-52阴离子交换柱和Sephadex G-200层析柱对粗多糖进行分离纯化,获得TLMPS-0、TLMPS-1和TLMPS-3均一多糖组分。采用化学组成分析、UV-vis、FTIR、刚果红实验对3种多糖组分进行结构分析,并检测了多糖清除自由基的能力和还原力。结果表明,奶油栓孔菌菌丝体多糖最优提取工艺为：提取温度99℃、料液比1:30 (g/mL)、提取时间5h,提取次数2次。在此工艺条件下,多糖提取率为4.01%。TLMPS-0、TLMPS-1和TLMPS-3的糖醛酸含量分别为12.91%±0.44%、8.24%±0.22%、7.50%±0.66%,硫酸基含量分别为22.24%±1.88%、14.55%±0.56%、18.68%±0.69%,并且证明TLMPS-0是一种α-吡喃型多糖或β-吡喃型多糖,而TLMPS-1是一种β-吡喃型多糖,均不具备三螺旋空间构象,此外,3种多糖组分均具有一定的清除DPPH自由基、ABTS自由基、羟基自由基的能力和铁离子还原能力,其中TLMPS-0抗氧化活性最强。研究结果为奶油栓孔菌多糖的功能研究与挖掘提供了研究基础与理论依据。     

Structural determination of the capsular polysaccharide of Neisseria meningitidis group I: a two-dimensional NMR analysis

The capsular polysaccharide antigen of Neisseria meningitidis group I was isolated by Cetavlon precipitation and purified by ion-exchange chromatography. The structure of the I polysaccharide was determined largely by comprehensive proton and carbon-13 nuclear magnetic resonance studies in which both one-dimensional and two-dimensional experiments were carried out directly on the I polysaccharide. The I polysaccharide is composed of the repeating unit----4)alpha-L-GulpNAcA(1----3)[4-OAc]beta-D-ManpNA-cA(-- --in which the former residue adopts the 4C1 (L) conformation and the latter residue adopts the 4C1 (D) conformation. The one-bond coupling between the anomeric carbon and proton (1J13C,H) of the 2-acetamido-2-deoxy-beta-D-mannuronopyranosyl residue is not consistent with its beta-D configuration. This anomalous value of 1J13C,H for this residue is due to through-space anisotropy effects on its anomeric proton, generated by the proximity of the carboxyl group of the neighboring 2-acetamido-2-deoxy-alpha-L-guluronopyranosyl residue. The O-acetyl substituents of the I polysaccharide are essential for its antigenicity to group I polysaccharide-specific antibodies.     

高原链带藻抗氧化蛋白分离纯化与结构鉴定

【背景】微藻Desmodesmus sp. QL96从我国西藏地区分离得到,经形态鉴定隶属于链带藻属。前期研究发现,这种链带藻在4℃和25℃下均可生长,在25℃生长时,干细胞中蛋白质含量可高达71.68%(质量分数),而且蛋白粗提物具有一定的抗氧化活力。【目的】分离纯化Desmodesmus sp. QL96细胞中具有抗氧化活力的蛋白质,并对其结构进行鉴定。【方法】应用柱层析的方法分离纯化Desmodesmus sp. QL96细胞中具有抗氧化活力的蛋白质,通过化学发光法和细胞学实验对该蛋白的抗氧化活性进行检测,并通过质谱技术对其一级结构进行检测。【结果】Desmodesmus sp. QL96细胞中抗氧化蛋白的含量占微藻细胞干重的11.40%(质量分数);纯化的Desmodesmus sp. QL96抗氧化蛋白在一定浓度范围内对OH-、DPPH、ABTS自由基和H2O2具有较好的清除率(超过60%),细胞学实验显示其对H2O2诱导的HepG2细胞氧化损伤具有抑制作用,验证了其抗氧化功能;通过质谱技术检测了Desmodesmus sp. QL96抗氧化蛋白的氨基酸序列,并进行了生物信息学分析,结果显示,这种蛋白质的理论分子量为44.8 kD、pI 5.79,与NCBI中目前已知的其他物种蛋白质的相似性不超过59%。【结论】Desmodesmus sp. QL96可能生产一种具有抗氧化活性的新蛋白质,后续将对其转录本进行分析,验证其遗传信息的同源性,并分析其规模化生产和应用前景。     

Anti-tumour components of the culture filtrates from Tricholoma sp.

The anti-tumour component (Fraction A) found in the culture filtrates of a local mushroom, Tricholoma sp. (strain STC20-T1), was purified using DEAE-cellulose ion exchange chromatography and Sepharose CL-4B gel filtration. Of its two purified sub-fractions, A-1 and A-2, only the latter showed anti-tumor activity. When Fraction A-2 was treated with cetyltrimethylammonium hydroxide and chloroform/butanol (24:1, v/v), it behaved as a proteinbound polysaccharide, with a molecular mass estimated to be 154 kDa by gel filtration. It contained 40% polysaccharide, which consisted of fucose, galactose, glucose, arabinose and mannose, and 30.5% protein, the amino-acid composition of which was determined. Fraction A-2 could inhibit the growth of Sarcoma-180 implanted in mice intraperitoneally and subcutaneously, with no sign of toxicity, at a dose of 20 mg/kg.day for 10 days.