Purification,structural features,antioxidant and moisture-preserving activities of an exopolysaccharide from Lachnum YM262

A water-soluble exopolysaccharide, designated as LEP-2a, was isolated from Lachnum YM262 and purified by DEAE-Cellulose 52 and Sepharose CL-6B chromatographic columns. LEP-2a was a homogeneous polysaccharide, with a molecular weight of 1.52 × 10⁵ Da. It was composed of mannose and galactose in a molar ratio of 20.6:1.0. Its structural features were investigated and elucidated by methylation analysis, periodate oxidation and Smith degradation, FT-IR and NMR spectroscopy. Based on obtained data, the backbone of LEP-2a consisted of 1,2-linked-α-d-mannose, 1,3-linked-α-d-mannose, 1,2,6-linked-α-d-mannose and 1,3-linked-β-d-galactose and the side chains were attached to the backbone at O-6 position of 1,2,6-linked-α-d-mannose. In vitro antioxidant activity assay proved that LEP-2a possessed significant scavenging activities on superoxide, hydroxyl and DPPH radical. Furthermore, LEP-2a had strong in vitro moisture-absorption and -retention capacities as compared to chitosan and glycerol. These results suggested that LEP-2a might have a good potential to be applied as a multifunctional cosmetic additive in cosmetics.     

Bioactivities of water-soluble polysaccharides from fruit shell of Camellia oleifera Abel: Antitumor and antioxidant activities

Polysaccharides were extracted from fruit shell of Camellia oleifera Abel. Fruit shell of Camellia oleifera Abel polysaccharide (WEP2) was a water-soluble compound. Its molecular weight was about 362 kDa. HPLC analysis showed that this polysaccharide was composed of rhamnose, fucose, arabinose, mannose, galactose and glucose in the molecular ratio of 4.05, 11.62, 1.78, 3.91, 8.76 and 27.06, respectively. The broad intense characteristic peak around 3463 cm⁻¹ due to the hydroxyl stretching vibration of the polysaccharide was observed in the polysaccharide. The characteristic absorption bands at 852 cm⁻¹ and 893 cm⁻¹ indicated that WEP2 contained both α-glycosidic and β-glycosidic linkages. WEP2 exhibited remarkable antitumor activity against Sarcoma180 cell compared to the negative control group. At the highest dose 40 mg/kg days, the tumor inhibition rate reached 65.2%. The scavenging effects of WEP2 to hydroxyl radical and superoxide radical anion were 72.5% and 86.3% at a concentration of 1.0 mg/ml, respectively.     

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.     

Extraction, characterization of polysaccharides from Morinda officinalis and its antioxidant activities

Morinda officinalis How (Rubiaceae) is widely used for medicinal purposes in China, Korea and Japan. Polysaccharides have also been determined and recently were shown to have protective effect against bone loss. A large number of polysaccharides present in the M. officinalis were successively extracted with hot water after preliminary treatments. The UV scan was used to analyse quality and purity of the polysaccharides from M. officinalis (MOP). Result indicated that had a better purity and quality and was free of proteins. HPLC showed that MOP mainly consisted of glucose (retention time, 8.691) and fructose (retention time, 9.245) with a molar ratio of 1.29:2.71. On the basis of analysis of chemical components, antioxidant activity of MOP was evaluated. The obtained results showed that MOP supplementation resulted in (a) increased antioxidant enzyme activities, and (b) decreased MDA level in rats.     

Effect of acetylation on antioxidant and cytoprotective activity of polysaccharides isolated from pumpkin (Cucurbita pepo, lady godiva)

Acetylation of pumpkin (Cucurbita pepo, lady godiva variety) polysaccharide using acetic anhydride with pyridines as catalyst under different conditions was conducted to obtain different degrees of acetylation on a laboratory scale. Furthermore, antioxidant activities and cytoprotective effects of pumpkin polysaccharide and its acetylated derivatives were investigated employing various established in vitro systems. Results showed that addition of pyridine as catalyst could increase the degree of substitution, whereas volume of acetic anhydride had little effect. The acetylated polysaccharides in DPPH scavenging radical activity assay, superoxide anion radical activity assay and reducing power assay exhibited higher antioxidant activity than that of unmodified polysaccharide. H₂O₂-induced oxidative damages on rat thymic lymphocyte were also prevented by pumpkin polysaccharide and its acetylated derivatives and the derivatives presented higher protective effects. On the whole, acetylated polysaccharide showed relevant antioxidant activity both in vitro and in a cell system.     

Antioxidant and immunological activities of water-soluble polysaccharides from Aconitum kusnezoffii Reichb

Aconitum kusnezoffii Reichb., one of the earliest recorded toxic species of genus Aconitum, has been used as traditional Chinese medicine and medicinal diet over the last 2500 years to treat heart failure congestion, neuralgia, rheumatism and gout, etc. In the present paper, four water-soluble polysaccharide fractions isolated from the tubers of A. kusnezoffii Reichb. were studied the antioxidant and immunological activities for the first time. In vitro antioxidant assays indicated that fraction WKCP-A had noticeable scavenging activities on DPPH radical, hydroxyl radical, superoxide anion, H₂O₂ and self-oxidation of 1,2,3-phentriol, ferrous ion-chelating ability and reducing power. Moreover, the in vivo immunological assay exhibited that fractions WKCP-A and WKHP could more significantly enhance splenic lymphocyte proliferation and macrophage phagocytosis than other fractions. Therefore, the water-soluble polysaccharides from A. kusnezoffii Reichb., especially WKCP-A, have the potential to be explored as novel natural antioxidants and immunostimulating agents for using in functional foods or medicine.     

Study of antioxidant activities of sulfated polysaccharides from Laminaria japonica

The composition, molecular weight and in vitro antioxidant activity of various sulfated polysaccharides obtained by anion exchange chromatography, acid hydrolysis and radical process degradation of the crude sulfated polysaccharide extracted from Laminaria japonica were compared. The low sulfated F-A2, with a peak-molecular weight (Mp) of 5–15 kDa, 14.5% sulfated ester and 21.8% glucuronic acid, exhibited a very strong antioxidant activity on superoxide and hydroxyl radicals, with activity even higher than that of large molecular weight fractions F-A and F-B. However, highly sulfated fractions with a peak-molecular weight below 15 kDa had much lower antioxidant activities than other fractions. These results indicated that the sulfate group of the low molecular weight fractions represents a physical block for the reaction with oxygen radicals. The chemical properties and antioxidant activities of sulfated polysaccharide fractions obtained by radical process degradation of crude sulfated polysaccharide were quite different from those obtained by acid hydrolysates. By radical process degradation, the high molecular weight was decreased to give LM2 (Mp 8 kDa) and LM1 (Mp 1.5 kDa), with a yield of 40% and 15%, respectively. LM2 was enriched with fucose and sulfated ester, while containing low amounts of glucuronic acid. The antioxidant activity showed that LM2 was unable to scavenge either superoxide or hydroxyl radical, which suggested that radical process degradation targeted mainly ascopyllan-like species rich in glucuronic acid, while the fraction rich in sulfated l-fucose remained unchanged. However, LM1 with Mp 1.5 kDa still retained apparent scavenging ability for superoxide radical, although it contained no glucuronic acid and certain amounts of galactose and mannose as main neutral sugars. These result suggest that the antioxidant activity of sulfated polysaccharides is apparently related not only to molecular weight and sulfated ester content, as previously determined, but also to glucuronic acid and fucose content.     

Phenolic compounds from the roots of Ochna schweinfurthiana and their antioxidant and antiplasmodial activities

An investigation of compounds extracted from Ochna schweinfurthiana roots with ethyl acetate led to the isolation of three new compounds 4⿴-methoxylophirone A (1), 4,4⿲,4⿴⿿trimethoxylophirone A (2) and (4E;7Z)-3,8-dicarboxy-1-(O-β-d-glucopyranosyl-(1 ⿿ 6)-O-β-d-glucopyranosyl-2,9-dihydroxyhexeicosa-4,7-diene (3). Six known compounds were also identified, including Calodenone (4), Calodenine B (5), Lophirone A (6), Gerontoisoflavone A(7), 16α,17-dihydroxy-ent-kauran-19-oic acid (8) and 3β-O-d-glucopyranosyl-β-sitosterol (9). This report describes the first time that compounds 4-8 have been isolated from this plant, while 8 has never been identified in the genus Ochna. Some of the isolated compounds were evaluated for their antiplasmodial activity against the chloroquine-sensitive Plasmodium falciparum strain 3D7 and antioxidant activity using DPPH radical scavenging and Ferric reducing-antioxidant power (FRAP) assays. Compound 5 exhibited prominent radical scavenging and FRAP activities, while 7 had weak activity. Compound 1 showed good in vitro anti-plasmodial activity. The structures of the isolated compounds were elucidated by spectroscopic methods and comparisons with prior data in the literature.     

Structural analysis of water-soluble polysaccharides in the fruiting body of Dictyophora indusiata and their in vivo antioxidant activities

The water-soluble Dictyophora indusiata polysaccharides (DIP) were extracted from the fruiting body of D. indusiata. The structural features of purified DIPs I and II were investigated. The results indicated that DIP I was composed of glucose (Glc) and mannose (Man) with molecular weight of 2100 kDa, while DIP II comprised of xylose (Xyl), galactose (Gal), glucose (Glc) and Man with molecular weight of 18.16 kDa. The glycosidic linkage of DIP I was composed of →1)-Glc-(6→: →1)-Man-(3,6→ with the ratio of 5.6:1.0, while DIP II was composed of →1)-Glc-(6→: →1)-Man-(3,6→: →1)-Xyl-(5→: →1)-Gal-(3→: →1)-Gal-(6→: with the ratio of 4.9: 15.5: 7.8: 1.0: 5.7. DIP significantly (P < 0.05) decreased the malondialdehyde (MDA), lipofuscin levels and increased the superoxide dismutase (SOD), glutathione peroxidase (GSH-Px) activities of mice. The strong in vivo antioxidant activity indicated DIP had great potential as functional food.     

Chemical composition and antioxidant activities of different polysaccharides from the roots of Angelica dahurica

The total crude polysaccharides (CADPs), isolated from the roots of Angelica dahurica by H(2) O extraction, EtOH precipitation, and dialysis, and the four fractions ADP1, ADP2, ADP3, and ADP4, obtained by gel filtration of the CADPs, were analyzed to characterize their composition and evaluated for their antioxidant activity using different in vitro tests such as the malondialdehyde (MDA)-production, the ferrous ion (Fe(2+) )-chelating, and the HO(.) radical-scavenging assays. The predominant neutral monosaccharides in the four fractions were identified as arabinose, galactose, and glucose, while the composition and ratio of the monosaccharides were different between the fractions. The CADPs and its fractions were found to significantly inhibit lipid peroxidation, chelate Fe(2+) , and scavenge HO(.) radicals, indicating that these polysaccharides possessed antioxidant activity. Among the four fractions, ADP4 exhibited the strongest antioxidant activity, which was stronger than that of the control antioxidant vitamin E (Vit E). Taken together, the chemical composition of these polysaccharides might affect their antioxidant activity, and ADP4 could be explored as a source of potential novel natural antioxidants for food and pharmaceutical purposes.     

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.     

In vitro antioxidant activities of acetylated, phosphorylated and benzoylated derivatives of porphyran extracted from Porphyra haitanensis

Porphyran extracted from red algae Porphyra haitanensis is a sulfated polysaccharide, which possesses excellent antioxidant activities. In this study, we prepared the acetylated, phosphorylated and benzoylated derivatives of porphyran. And then the antioxidant activities of all the samples were investigated including scavenging effects of superoxide and hydroxyl radicals and reducing power. The results of chemical analysis and FT-IR spectrum showed the modifications of porphyran were successful. And in addition, we found that certain derivative exhibited stronger antioxidant activity than raw material. And the mechanism of the structure–function relationship of these derivatives needs to be attended to.     

菠萝叶片色泽、色素及抗氧化活性的关系

以菠萝22个栽培品种的叶片为实验材料,测定其5种色泽参数（L^*、a^*、b^*、c^*和h^*值）、5种色素（叶绿素、类胡萝卜素、花青苷、类黄酮和总酚）含量及3种抗氧化活性指标（ABTS、DPPH自由基和亚硝酸盐的清除能力）,并进行相关性分析。研究结果显示,色泽参数a^*和h^*值可以作为菠萝叶片指示色泽、主要色素含量和抗氧化活性变化的重要指标;菠萝叶片主要色素组成是叶绿素、类黄酮和总酚,且含有少量的花青苷,几乎不含类胡萝卜素。相关性分析结果显示,菠萝叶片类黄酮和总酚含量均与3种抗氧化活性指标极显著正相关,而叶绿素含量与其它指标相关性未达到显著水平,类黄酮和总酚是菠萝叶片抗氧化活性的主要功效成分。     

In vitro antioxidant and antitumor activities of polysaccharides extracted from Asparagus officinalis

Ultrasonic circulating extraction technology was applied for the polysaccharide extraction from Asparagus officinalis. The crude polysaccharides were deproteinized by Sevag method and three main polysaccharide fractions, AOP-4, AOP-6 and AOP-8 were obtained by fractional precipitation with gradient concentrations of ethanol (40%, 60% and 80%). The in vitro antitumor and antioxidant activities of the polysaccharide fractions were evaluated by MTT assay and free radical-scavenging assay, respectively. Deproteinized AOPs showed higher antioxidant and antitumor activities than crude AOP. AOP-4 with molecular weight 5.75 × 10⁴ Da showed significant function of scavenging hydroxyl radical. Three AOP fractions had significant antitumor activity against HeLa and BEL-7404 cells in a dose dependent manner. Furthermore, the inhibit activity of AOP-4 against HeLa cells was higher than those of other AOPs and the inhibition rate reached 83.96% at the concentration of 10 mg/mL. These results indicated that the AOP might be useful for developing natural safe antitumor drugs or health food.     

Nephroprotective,cytotoxic and antioxidant activities of Euphorbia paralias

ObjectiveTo investigate the effect of the ethyl acetate fraction of the aerial parts of E. paralias L. F. Euphorbiaceae on nephroprotective, cytotoxic, and antioxidant.Methodsdifferent spectroscopic and spectrophotometric methods were applied to identify phytoconstituents. The nephroprotective potential of E. paralias ethyl acetate fraction (Ep EtOAc) was evaluated in male rats with thioacetamide-induced kidney injury, as wll as cytotoxic activity was evaluated using a viability assay, and the antioxidant activity was evaluated using the DPPH method. Results: quantitative estimation of total phenolics and flavonoids of E. paralias was performed using unique spectrophotometric methods. The polyphenolic compounds gallic acid (1), ellagic acid (2), kaempferol-3-O-(6″-O-galloyl-β-D-glucopyranoside) (3), quercetin-3-O-β-D-glucopyranoside (4) and quercetin-3-O-β-D-arabinoside (5) were isolated from the ethyl acetate fraction of the aerial parts of E. paralias. The thioacetamide administration resulted in marked nephrotoxicity, but pretreatment with Ep EtOAc significantly attenuated the nephrotoxicity through alteration of kidney biomarkers, thereby improving the redox status of the tissue and restoring serum biochemical parameters nearly to normal levels. This study revealed a significant cytotoxic and strong antioxidant effect. Conclusion: we conclude that the Ep EtOAc may be used in the future as nephroprotective, cytotoxic, and antioxidant agent derived from a natural source.     

Plant regeneration from encapsulated somatic embryos of Carica papaya L.

Carica papaya L. (papaya) single somatic embryos (2.0 mm diameter) produced in a high-frequency liquid production system were encapsulated in two different synthetic encapsulation compounds. The frequency of regeneration from encapsulated embryos was significantly affected by (1) the concentration of sodium alginate, (2) the presence or absence of nutrient salts in the capsule, and (3) the duration of exposure to calcium chloride. A 2.5% sodium alginate concentration in a half-strength MS salts base resulted in significantly higher germination frequencies than other treatments. A relatively short (10 min) exposure to CaCl₂ provided uniform encapsulation of embryos and the highest frequencies of successful germination (77.5%). Germinated artificial seeds produced normal plantlets. Received: 12 March 1997 / Revision recieved: 24 June 1997 / Accepted: 18 July 1997     

Evaluation of in vitro antioxidant,antimicrobial, genotoxic and anticancer activities of lichen Cetraria islandica

In this study, the antioxidant, antimicrobial, genotoxic and anticancer activities of Cetraria islandica methanol extract were determined by using free radical and superoxide anion scavenging activity, reducing power, determination of total phenolic compounds and flavonoid contents, broth microdilution minimal inhibitory concentration against five bacterial and five fungal species, cytokinesis block micronucleus (MN) assay on peripheral blood lymphocytes (PBLs) and the microculture tetrazolium test on FemX (human melanoma) and LS174 (human colon carcinoma) cell lines. As a result of the study, we found that C. islandica methanol extract exhibited moderate free-radical-scavenging activity with IC₅₀ values 678.38 μg/ml. Moreover, the tested extract had effective reducing power and superoxide anion radical scavenging. The minimal inhibitory concentration values against the tested microorganisms ranged from 0.312 to 5 mg/ml. The extract increased MN frequency in a dose dependent manner, but it was significant in higher tested concentrations (50, 100 and 200 μg/ml). No significant differences were observed between NDI values in all treatments and untreated PBLs. In addition, the tested extract had strong anticancer activity towards both cell lines with IC₅₀ values of 22.68 and 33.74 μg/ml. It can be concluded that the tested extract exhibited a certain level of in vitro antioxidant, antimicrobial, genotoxic and anticancer activities.     

Isopestacin,an isobenzofuranone from Pestalotiopsis microspora,possessing antifungal and antioxidant activities

Isopestacin is an isobenzofuranone obtained from the endophytic fungus Pestalotiopsis microspora. While a few other isobenzofuranones are known from natural sources, isopestacin is the only one having a substituted benzene ring attached at the C-3 position of the furanone ring. The compound was isolated from culture broths of the fungus and crystallized and its structure was determined by X-ray crystallography. Both proton and carbon NMR spectral assignments are also reported for isopestacin. This compound possesses antifungal activity and, as measured by electron spin resonance specroscopy, it also behaves as an antioxidant scavenging both superoxide and hydroxy free radicals.     

Synthesis,antioxidant and antiproliferative activities of 1,3,4-thiadiazoles derived from phenolic acids

Two 2-amino-1,3,4-thiadiazoles containing phenolic hydroxyl groups were combined with different carboxylic acid chlorides giving sixteen amide derivatives with good antioxidant and antiproliferative potential. The compound 3′c with an adamantane ring displayed excellent DPPH radical scavenging activity and good cytotoxic activity against human acute promyelocytic leukemia HL-60 cells, while 1,3,4-thiadiazole 3′h with 4-chlorophenyl moiety was found to be the most effective in inhibition of survival of lung carcinoma A549 cells. All examined thiadiazoles except 3a and 3′a exerted higher cytotoxic activities on A549 and HL-60 cancer cells when compared with normal fibroblasts MRC-5, pointing to selectivity in their antiproliferative action. Some of the most active novel compounds 3c, 3′c, 3′g and 3′h induced significant increase in the percentage of HL-60 cells in the subG1 cell cycle phase in comparison with the control cells. The induction of cell death in HL-60 cells by these compounds was at least partially dependent on activation of caspase-3 and caspase-8. The compounds 3c and 3′c exerted strong antiangiogenic activity. Furthermore, compounds 3c, 3′c, 3′g and 3′h showed the ability to down-regulate the MMP2 and VEGFA expression levels in the treated HL-60 cells when compared with the control cell samples.     

Phenylpropanoid acid esters from Korean propolis and their antioxidant activities

Ten phenylpropanoic acid esters were isolated from an ethanolic extract of Korean propolis. Their structures were elucidated by spectroscopic methods including NMR and ESI-MS. Caffeic acid esters with catechol moiety exhibited significant ABTS and DPPH radical scavenging activity and protective effect against DNA damage by a Fenton reaction.