Chemical structure and biological activity of the (1 → 3)-linked ß-D-glucan isolated from marine diatom Conticribra weissflogii.

Several polysaccharides are considered to be "biological response modifiers" (BRM) - these refer to biomolecules that augment immune responses and can be derived from a variety of sources. Microalgae produce a diverse range of polysaccharides and could be an excellent source of BRM. Here, we describe the chemical structure and biological activity of water-soluble polysaccharide isolated from the marine diatom Conticribra weissflogii. Using chemical and NMR spectroscopic methods, the polysaccharide was identified as a (1 â†’ 3)-linked ß-D-glucan with a low proportion of C-6 substitution by single ß-glucose units. The biological activity of this low molecular weight ß-glucan (11.7 kDa) was investigated with respect to glioblastoma cell lines (U87 MG and U251) and macrophages (RAW 264.7). We observed that this ß-D-glucan did not exhibit cytotoxic activity against glioblastoma cells, but did enhance the phagocytic activity of macrophages, suggesting that it possesses immunomodulatory properties.

Obtaining Hexoses from Chitosan through Depolymerization with Nitrous Acid.

BACKGROUND AND OBJECTIVE: Residues from shrimp farming have a great potential for sugar production and the production of derivatives for the low-carbon chemical industry. Obtainment of bioactives from chitosan has been extensively investigated using different methodologies. The purpose of this work was to study the chitosan depolymerization reaction aiming at the production of monomers without the use of additional enzymes or mineral acids. MATERIALS AND METHODS: In this work, we systematically study the effect of sodium nitrite concentration and reaction conditions (pH and temperature ranges) with acetic acid as the solvent on the chitosan depolymerization reaction aiming at the production of monomers, specifically 2,5- anhydromannose, without the use of additional enzymes or mineral acids. RESULTS: The results indicate that only a small range of reaction conditions and nitrite concentrations allow for obtaining the monomer, while in most combinations of these parameters, oligomers are obtained. We found that the temperature decisively affects the reaction yield, with the attainment of 2,5-anhydromannose favored at lower temperatures. CONCLUSION: The method proved to be simple and easy to perform allowing to obtain 2,5- anhydromannose with the use of low-cost reagents. This monomer can be converted into several derivatives for industrial application (5-Hydroxymethylfurfural, ethanol, etc.).

Advances in microalgal cell wall polysaccharides: a review focused on structure, production, and biological application.

Microalgae have been shown to be useful in several biotechnological fields due to their feasible cultivation and high-value biomolecules production. Several substances of interest produced by microalgae, such as: proteins, lipids, and natural colorants, have already been explored. Based on the continuing demand for new natural molecules, microalgae could also be a valuable source of polysaccharides. Polysaccharides are extremely important in aquaculture, cosmetics, pharmaceutical, and food industries, and have great economic impact worldwide. Despite this, reviews on microalgal polysaccharide production, biological activity, and chemical structure are not abundant. Moreover, techniques of microalgal cultivation, coupled with carbohydrate production, need to be clarified in order to develop forward-looking technologies. The present review provides an overview of the main advances in microalgal cell wall polysaccharide production, as well as their associated potential biological applications and chemical structure. Several studies on future prospects, related to microalgae are presented, highlighting the key challenges in microalgal polysaccharide production.

Ulva intestinalis Extract Acts as Biostimulant and Modulates Metabolites and Hormone Balance in Basil (Ocimum basilicum L.) and Parsley (Petroselinum crispum L.).

Natural elicitors from macroalgae may affect plant secondary metabolites. Ulvan is a sulfated heteropolysaccharide extracted from green seaweed, acting as both a plant biotic protecting agent, and a plant elicitor, leading to the synthesis of signal molecules. In this work, the aqueous extract of Ulva intestinalis L., mainly composed of ulvan, was used as foliar-spraying treatment and its eliciting effect was investigated in basil (Ocimum basilicum L.) and parsley (Petroselinum crispum L.). Antioxidant metabolites (polyphenols and carotenoids), volatile compounds (both in headspace emissions and hydrodistilled essential oils), and hormones (jasmonic acid, salicylic acid, salicylic acid 2-O-ß-D-glucoside, abscisic acid, and azelaic acid) were quantified. The foliar-spraying treatment with U. intestinalis extract increased salicylic acid and its ß-glucoside in parsley; in basil, it induced the accumulation of jasmonic and abscisic acids, indicating the presence of a priming effect. In basil, the elicitation caused a change of the essential oil (EO) chemotype from methyl eugenol/eugenol to epi-α-cadinol and increased sesquiterpenes. In parsley EO it caused a significant accumulation of 1,3,8-p-menthatriene, responsible of the typical "parsley-like" smell. In both species, the phenylpropanoids decreased in headspace and EO compositions, while the salicylic acid concentration increased; this could indicate a primarily defensive response to U. intestinalis extract. Due to the evidenced significant biological activity, U. intestinalis extract used as an elicitor may represent a suitable tool to obtain higher amounts of metabolites for optimizing plant flavor metabolites.

Rice vinasse treatment by immobilized Synechococcus pevalekii and its effect on Dunaliella salina cultivation.

The development of new strategies in microalgal studies represents an outstanding opportunity to mitigate environmental problems coupled with biomass production at a reduced cost. Here we present a combined bioprocess for the treatment of rice vinasse using immobilized cyanobacteria Synechococcus pevalekii in alginate beads followed by the use of the treated vinasse as a culture medium for Dunaliella salina biomass production. Cyanobacterial-alginate beads showed a chlorophyll a production of 0.68 × 10-3 mg bead-1 and a total carotenoid production of 0.64 × 10-3 mg bead-1. The first step showed a decrease in nitrate (91%), total solids (29%), and ions. Addition of treated vinasse into D. salina cultivation resulted in a significant increase in cell replication of about 175% (optimized cultivation). The use of natural seawater drastically reduced the medium cost to US$4.75 per m3 and the addition of treated vinasse has the potential to reduce it even more (up to 69%). This study not only provides an insight on the use of cyanobacteria for rice vinasse treatment but also demonstrates a promising lower-cost medium for marine microalgal biomass production with biotechnological purposes.

Lignin from oil palm empty fruit bunches: Characterization, biological activities and application in green synthesis of silver nanoparticles.

Lignin was extracted from oil palm empty fruit bunches under four different conditions. The lignin samples were characterized and employed in the green synthesis of silver nanoparticles. Two-dimensional HSQC NMR analysis showed that lignins extracted under more aggressive conditions (3.5% acid, 60 min) exhibited less signals and thus, presented a more degraded chemical structure. Additionally, those lignins obtained under harsh conditions (3.5% acid, 60 min) exhibited higher antioxidant capacity than those obtained under mild conditions (1.5% acid, 20 min). Formation of lignin-mediated silver nanoparticles was confirmed by color change during their synthesis. The surface plasmon resonance peaks (423-427 nm) in UV-visible spectra also confirmed the synthesis of AgNPs. AgNPs showed spherical shape, polycrystalline nature and average size between 18 and 20 nm. AgNPs, in suspension, presented a negative Zeta potential profile. Lignin was assumed to contribute in the antioxidant capacity exhibited by AgNPs. All AgNPs presented no significant differences on the disk diffusion antimicrobial susceptibility test against E. coli. The minimum inhibitory concentration of HAL3-L AgNPs (62.5 µg·mL-1) was better than other physicochemically produced AgNPs (100 µg·mL-1).

Pentose-rich hydrolysate from oil palm empty fruit bunches for ß-glucan production using Pichia jadinii and Cyberlindnera jadinii.

Pentose-rich hydrolysate obtained from dilute acid pretreatment of oil palm empty fruit bunches was successfully consumed by pentose-consuming yeasts: Cyberlindnera jadinii (Cj) and Pichia jadinii (Pj). Nitrogen supplementation and no additional detoxification step were required. Pj produced 5.87 g/L of biomass using a C/N ratio of 14 after 120 h of fermentation, with xylose consumption of 71%. Cj produced 10.50 g/L of biomass after 96 h of fermentation with C/N ratio of 11.5, with maximum xylose consumption of 85%. ß-glucans, high value-added macromolecules, were further extracted from the yeast biomass, achieving yields of 3.1 and 3.0% from Pj and Cj, respectively. The isolated polysaccharides showed a chemical structure of ß-(1,3)-glucan with residues of other molecules. Additionally, ß-(1,6) branches seems to have been broken during isolation process. Further studies assessing ß-glucans production at industrial scale should be carried out looking for nitrogen sources and optimizing the ß-glucan isolation method.

Effects of different culture media on physiological features and laboratory scale production cost of Dunaliella salina.

Microalgal cultivation system depends on optimal parameters obtained from laboratory conditions to overcome high-value compounds production and decrease cost. In this study, the laboratory-scale cultivation of Dunaliella salina was performed to explore the cost and biochemical effects on biomass cultivated using F/2, Conway, and Johnson media. D. salina cultivation was monitored by cell counting, dry biomass measurements and biochemical analyses. Photosynthetic pigment profiles were identified and quantified through high-performance liquid chromatography (HPLC) whereas economic evaluation was based on media cost. Cellular growth parameters were significantly improved by Conway medium, whereas maximum accumulation of pigments, especially violaxanthin (0.855 mg g-1) and chlorophyll a (14.255 mg g-1) were observed when Johnson medium was used. Conway-biomass showed 43 % of total lipid content. This value represents 1.5 and 1.4 times higher than lipid content found in Johnson- and F/2-biomass, respectively. Furthermore, media cost presented a variation of US$1.17-49.62 for each 103 L of media mainly due to NaNO3, KNO3, and cyanocobalamin supplementation. Thus, biomass production showed a cost variation of US$4.64-301.61 per kg on a dry weight basis. These outcomes emphasize the suitability of laboratory parameters and cost comparison among biomass produced by different media.

A comparative study of extraction techniques for maximum recovery of bioactive compounds from Ganoderma lucidum spores / Estudio comparativo de técnicas de extracción para la máxima recuperación de compuestos bioactivos a partir esporas de Ganoderma lucidum

SUMMARY This study aimed at evaluating effective methods for breaking the hard and insoluble spores of Ganoderma lucidum to recover functional biomolecules. Rupture techniques were evaluated such as manual maceration (RM), maceration with spheres of various materials (BR), and microwave exposure plus maceration with steel/ chrome spheres (MBR1). Spore rupture was evaluated using UV-Vis spectroscopy, which showed vibrations of 2955, 1642, 1240, 1080 and 1746 cm-1 corresponding to changes in spore walls. The MBR1 extract contained the largest amounts of carbohydrates (19.80 mg.g-1 spores) and polyphenols (2.21 mg.g-1 spores), whereas the BR extract had higher antioxidant activity (57.22%Inb DPPH). The MBR1 and BR extracts contained 62.2 and 73.5% glucose, respectively. Both methods also involved significant extraction of carbohydrates and proteins. The best way to extract biomolecules from spore walls is to perform a microwave heat treatment and break the walls with steel/chrome spheres; this produces large quantities of carbohydrates with antioxidant properties.

RESUMEN El objetivo de este estudio fue evaluar varios métodos de ruptura de las esporas de Ganoderma lucidum y extraer sus propiedades bioactivas. Para este propósito se evaluaron diferentes técnicas de rompimiento como: la maceración manual (RM), la maceración con esferas de diversos materiales (BR) y la exposición a microondas junto la maceración de las esporas con esferas de acero/cromo (MBR1). La ruptura de las esporas fue evaluada por espectroscopia UV-Vis, la cual mostró que las vibraciones 2955, 1642, 1240, 1080 y 1746 cm-1 correspondieron a cambios estructurales en las paredes de las esporas. El extracto MBR1 presento el mayor contenido de carbohidratos (19,80 mg.g-1) y polifenoles (2,21 mg.g-1), mientras que el extracto BR tuvo una mayor actividad antioxidante (57,22% Inb DPPH). Los extractos MBR1 y BR también presentaron en el análisis de monosacáridos un 62,2 y 73,5% de contenido glucosa. Como conclusión la mejor metodología para extraer biomoléculas de las paredes de las esporas de G. lucidum fueron el tratamiento térmico con microondas y la ruptura de las paredes con esferas de acero/cromo, porque este proceso permitió la extracción de una mayor cantidad de carbohidratos con posibles propiedades antioxidantes.

Modified soybean meal polysaccharide with high adhesion capacity to Salmonella.

Carbohydrates are known to act as analog receptors for bacteria and therefore are promising alternatives for the control and prevention of bacterial infections. The present study evaluated the chemical structure of modified soybean meal polysaccharides and their capacity to adhere enterobacteria (Salmonella Typhimurium) and to interfere with the bacteria adhesion to the known analogue receptors, using in vitro assays. For this, soybean meal suspensions were subjected to a thermochemical extraction process and structural analyses showed that the fraction with higher adhesion and adhesion-inhibition potential, SAP, was constituted by two types of polysaccharides: a partially depolymerized pectin, of high molar mass, composed of xylogalacturonan and rhamnogalacturonan regions (SAP1, 545.5 kDa), and a (1 → 4)-linked-ß-D-galactan of low molar mass (SAP2, 8.7 kDa). The results showed a high affinity of Salmonella for galactans, while high molar mass pectins showed no adhesion capacity. The chemical compositions of the fractions suggested that galactose could be responsible for the recognition process in the adhesion process. Other factors, such as structure and degree of polymerization of the polymers, may also be influencing the adhesion process. Modified soybean meal polysaccharides appear to be a promising alternative agent to antibiotics for the control and prevention of foodborne diseases.

Potential Utilization of a Polysaccharide from the Marine Algae Gayralia oxysperma, as an Antivenom for Viperidae Snakebites.

Worldwide, snakebites have serious implications for human health. The administration of antivenom is the official treatment used to reverse the toxic activities of envenomation. However, this therapy is not efficient to treat the local effects, leading to the amputation or deformity of affected limbs. As such, alternative treatments are needed. Here, we analyze the ability of a polysaccharide from the green marine alga Gayralia oxysperma (Go3) to inhibit the effects of venom from Bothrops jararaca and Lachesis muta. B. jararaca or L. muta venoms were incubated together with sulfated heterorhamnans from Go3, and the in vitro (coagulation, proteolytic, and hemolytic) and in vivo (hemorrhagic, myotoxic, edematogenic, and lethal) activities of venoms were assessed. Additionally, Go3 was injected before and after the injection of venoms, and the toxic activities were further tested. When incubated with the venoms, Go3 inhibited all activities, though results varied with different potencies. Moreover, Go3 neutralized hemorrhagic, myotoxic, and edematogenic activities when injected before or after injection with B. jararaca and L. muta venom. Go3 also blocked the coagulation of plasma in mice caused by the venoms in an ex vivo test. Therefore, Go3 has the potential to be used as antivenom for B. jararaca and L. muta bites, notably exhibiting higher efficacy on L. muta venom.

Protective Effect of the Sulfated Agaran Isolated from the Red Seaweed Laurencia aldingensis Against Toxic Effects of the Venom of the Snake, Lachesis muta.

Snakebite is a serious occupational hazard affecting mainly rural populations of tropical and subtropical developing countries. Lachesis muta (Bushmaster) bites are extremely serious but are rarely reported in the literature. Bushmaster envenomings are characterized by intense local pain, edema, neurotoxicity, hypotension, local hemorrhage, and dramatic systemic alterations. Antivenom treatment has regularly been used for more than a century; however, it fails to neutralize local tissue damage and hemorrhage, leading to morbidity or disabilities in victims. Thus, the production and clinical use of antivenom must be improved. The present work characterizes, for the first time, a sulfated polysaccharide from the red seaweed, Laurencia aldingensis, including its neutralizing effect on some toxic activities of L. muta venom. Chemical and spectroscopic analyses showed that L. aldingensis produces sulfated agarans with the A-units partially C-2 sulfated or 6-O-methoxylated presetting the B-units in the cyclized (3,6-anhydro-α-L-galactose) or in the non-cyclized form (α-L-galactose). The latter is significantly substituted by sulfate groups on C-6. In vitro and in vivo assays showed that this sulfated agaran inhibited hemolysis, coagulation, proteolysis, edema, and hemorrhage of L. muta venom. Neutralization of hemorrhagic activity was also observed when the agaran was administered by different routes and after or before the venom injection. Furthermore, the agaran blocked the edema caused by a phospholipase A2 isolated from the L. muta venom. Experimental evidence therefore indicates that the sulfated agaran of L. aldingensis has potential to aid antivenom therapy of accidents caused by L. muta venom and may help to develop more effective antivenom treatments of snake bites in general.

In vitro photodynamic inactivation of conidia of the phytopathogenic fungus Colletotrichum graminicola with cationic porphyrins.

Photodynamic inactivation (PDI) is an efficient approach for the elimination of a series of microorganisms; however, PDI involving phytopathogenic filamentous fungi is scarce in the literature. In the present study, we have demonstrated the photoinactivating properties of five cationic meso-(1-methyl-4-pyridinio)porphyrins on conidia of the phytopathogen Colletotrichum graminicola. For this purpose, photophysical properties (photostability and (1)O2 singlet production) of the porphyrins under study were first evaluated. PDI assays were then performed with a fluence of 30, 60, 90 and 120 J cm(-2) and varying the porphyrin concentration from 1 to 25 µmol L(-1). Considering the lowest concentration that enabled the best photoinactivation, with the respective lowest effective irradiation time, the meso-(1-methyl-4-pyridinio)porphyrins herein studied could be ranked as follows: triple-charged 4 (1 µmol L(-1) with a fluence of 30 J cm(-2)) > double-charged-trans2 (1 µmol L(-1) with 60 J cm(-2)) > tetra-charged 5 (15 µmol L(-1) with 90 J cm(-2)) > mono-charged 1 (25 µmol L(-1) with 120 J cm(-2)). Double-charged-cis-porphyrin 3 inactivated C. graminicola conidia in the absence of light. Evaluation of the porphyrin binding to the conidia and fluorescence microscopic analysis were also performed, which were in agreement with the PDI results. In conclusion, the cationic porphyrins herein studied were considered efficient photosensitizers to inactivate C. graminicola conidia. The amount and position of positive charges are related to the compounds' amphiphilicity and therefore to their photodynamic activity.

Acid heteropolysaccharides with potent antileishmanial effects.

The present study investigated in vitro the effects of sulphated heterorhamnan (Go3), iota-/nu-carrageenans (G3d and EHW-I) and arabinogalactan (ARAGAL) polysaccharides on macrophage activation and inhibition of intracellular amastigotes of Leishmania (L.) amazonensis. All the sulphated polysaccharides (Go3, G3d and EHW-I) promoted increased nitric oxide production varying from 71 to 110%. The leishmanicidal activity of all compounds was compared to the inhibition effect of Meglumine Antimoniate at 300µg/mL (∼79%), used as positive control. Inhibition of Leishmania (L.) amazonensis growth was 55% with 5µg/mL of Go3, 50% and 98% to G3d and EHW-I, respectively at 10µg/mL, and 88% with 10µg/mL of ARAGAL. The superoxide anion scavenging activity for the sulphated polysaccharides varied from approximately 30-55% at 10µg/mL. In conclusion, the results of the present study indicate the promising potential of these polysaccharides for the development of new alternative therapeutic agents against leishmaniasis.

Sulfated Galactan from Palisada flagellifera Inhibits Toxic Effects of Lachesis muta Snake Venom.

In Brazil, snakebites are a public health problem and accidents caused by Lachesis muta have the highest mortality index. Envenomation by L. muta is characterized by systemic (hypotension, bleeding and renal failure) and local effects (necrosis, pain and edema). The treatment to reverse the evolution of all the toxic effects is performed by injection of antivenom. However, such therapy does not effectively neutralize tissue damage or any other local effect, since in most cases victims delay seeking appropriate medical care. In this way, alternative therapies are in demand, and molecules from natural sources have been exhaustively tested. In this paper, we analyzed the inhibitory effect of a sulfated galactan obtained from the red seaweed Palisada flagellifera against some toxic activities of L. muta venom. Incubation of sulfated galactan with venom resulted in inhibition of hemolysis, coagulation, proteolysis, edema and hemorrhage. Neutralization of hemorrhage was also observed when the galactan was administered after or before the venom injection; thus mimicking a real in vivo situation. Moreover, the galactan blocked the edema caused by a phospholipase A2 isolated from the same venom. Therefore, the galactan from P. flagellifera may represent a promising tool to treat envenomation by L. muta as a coadjuvant for the conventional antivenom.

Investigation of anti-inflammatory and anti-proliferative activities promoted by photoactivated cationic porphyrin.

BACKGROUND: Photodynamic therapy (PDT) is a technique that uses light and a photosensitizer, converting local molecular oxygen into singlet oxygen, which eliminates a target unhealthy tissue. It has been increasingly used for the treatment of several diseases including skin disorders. Psoriasis is a chronic inflammatory skin disease expressing immune and hyperproliferative features. OBJECTIVE: This study aimed to evaluate the effect of the photosensitizer 5,10-diphenyl-15,20-di(N-methylpyridinium-4-yl)porphyrin (Di-cis-Py+) in in vivo models whereby some psoriasis-like parameters could be investigated. METHODS: The antiinflammation and antiproliferative activities of Di-cis-Py+ photoactivated was measured by myeloperoxidase (MPO) and N-acetyl-ß-d-glucosaminidase (NAG) enzyme activity assay, measurement of IL-6, IL-1ß and TNF-α levels, evaluation of proliferating cell nuclear antigen (PCNA) levels by immunohistochemistry and by Western blot. RESULTS: Treatment involving PDT and Di-cis-Py+ resulted in reduction of edema, cellular infiltration, proinflammatory cytokines, as well as reduced hyperproliferation of the epidermis. All the evaluated parameters were promoted by topical application of phlogistic agents and are similar to that observed in lesions of psoriatic skin. CONCLUSION: The results shows the advantage of topical application, do not cause apparently photosensitivity and have effects comparable to dexamethasone, a first-line drug for the treatment of the disease.

Two galactomannan preparations from seeds from Mimosa scabrella (bracatinga): Complexation with oxovanadium(IV/V) and cytotoxicity on HeLa cells.

Two galactomannans, GALMAN-A and GALMAN-B, were isolated from seeds of Mimosa scabrella (bracatinga), with deactivation and exposure to native enzymes, respectively. They were treated with oxovanadium(IV) and oxovanadium(V), designated (VO(2+)/VO(3+)) to form GALMAN-A:VO(2+)/VO(3+) and GALMAN-B:VO(2+)/VO(3+) complexes, respectively. The potentiometric studies provided the binding constants for the complexes and the resulting complexed species were a function of pH. (51)V NMR spectra of GALMAN-A:VO(2+)/VO(3+) and GALMAN-B:VO(2+)/VO(3+) at pH 7.8 and at 30 degrees C indicated the occurrence of two types of complexes formed by oxovanadium ions and galactomannans. GALMAN-A:VO(2+)/VO(3+) and GALMAN-B:VO(2+)/VO(3+) caused loss of HeLa cells viability at concentrations of 50-200microg/mL. GALMAN-A:VO(2+)/VO(3+) exhibited low toxicity for 24h, although GALMAN-B:VO(2+)/VO(3+) was extremely toxic, since 50microg/mL was sufficient to decrease HeLa cell viability after 48h by 60%. GALMAN-A gave rise to a slight increase in cell proliferation after 48h at 100microg/mL, whereas GALMAN-B promoted a slight decrease at concentrations of 50-100microg/mL. GALMAN-A:VO(2+)/VO(3+) and GALMAN-B:VO(2+)/VO(3+) exhibited a significant decrease in cell proliferation after 48h, each reaching 60% inhibition at 5-10microg/mL. The complexes which caused this effect were at concentrations 10 times lower than the uncomplexed polymers.