A natural sulfated polysaccharide, calcium spirulan, isolated from Spirulina platensis: in vitro and ex vivo evaluation of anti-herpes simplex virus and anti-human immunodeficiency virus activities

Different Antifungal Activity of Anabaena sp., Ecklonia sp., and Jania sp. against Botrytis cinerea

Water extracts and polysaccharides from Anabaena sp., Ecklonia sp., and Jania sp. were tested for their activity against the fungal plant pathogen Botrytis cinerea. Water extracts at 2.5, 5.0, and 10.0 mg/mL inhibited B. cinerea growth in vitro. Antifungal activity of polysaccharides obtained by N-cetylpyridinium bromide precipitation in water extracts was evaluated in vitro and in vitro at 0.5, 2.0, and 3.5 mg/mL. These concentrations were tested against fungal colony growth, spore germination, colony forming units (CFUs), CFU growth, and on strawberry fruits against B. cinerea infection with pre- and post-harvest application. In in vitro experiments, polysaccharides from Anabaena sp. and from Ecklonia sp. inhibited B. cinerea colony growth, CFUs, and CFU growth, while those extracted from Jania sp. reduced only the pathogen spore germination. In in vitro experiments, all concentrations of polysaccharides from Anabaena sp., Ecklonia sp., and Jania sp. reduced both the strawberry fruits infected area and the pathogen sporulation in the pre-harvest treatment, suggesting that they might be good candidates as preventive products in crop protection.

Mexican Microalgae Biodiversity and State-Of-The-Art Extraction Strategies to Meet Sustainable Circular Economy Challenges: High-Value Compounds and Their Applied Perspectives

In recent years, the demand for naturally derived products has hiked with enormous pressure to propose or develop state-of-the-art strategies to meet sustainable circular economy challenges. Microalgae possess the flexibility to produce a variety of high-value products of industrial interests. From pigments such as phycobilins or lutein to phycotoxins and several polyunsaturated fatty acids (PUFAs), microalgae have the potential to become the primary producers for the pharmaceutical, food, and agronomical industries. Also, microalgae require minimal resources to grow due to their autotrophic nature or by consuming waste matter, while allowing for the extraction of several valuable side products such as hydrogen gas and biodiesel in a single process, following a biorefinery agenda. From a Mexican microalgae biodiversity perspective, more than 70 different local species have been characterized and isolated, whereas, only a minimal amount has been explored to produce commercially valuable products, thus ignoring their potential as a locally available resource. In this paper, we discuss the microalgae diversity present in Mexico with their current applications and potential, while expanding on their future applications in bioengineering along with other industrial sectors. In conclusion, the use of available microalgae to produce biochemically revenuable products currently represents an untapped potential that could lead to the solution of several problems through green technologies. As such, if the social, industrial and research communities collaborate to strive towards a greener economy by preserving the existing biodiversity and optimizing the use of the currently available resources, the enrichment of our society and the solution to several environmental problems could be attained.

Design, synthesis, and biomedical applications of synthetic sulphated polysaccharides

This review summarizes the synthetic methods to sulphated polysaccharides, describes their compositional and structural diversity in regards to activity, and showcases their biomedical applications.

Extraction techniques and potential health benefits of bioactive compounds from marine molluscs: a review

Marine molluscs and their bioactive compounds are of particular relevance to the growing pool of nutraceutical resources under global investigation.

Sulfotransferase and Heparanase: Remodeling Engines in Promoting Virus Infection and Disease Development

An extraordinary binding site generated in heparan sulfate (HS) structures, during its biosynthesis, provides a unique opportunity to interact with multiple protein ligands including viral proteins, and therefore adds tremendous value to this master molecule. An example of such a moiety is the sulfation at the C3 position of glucosamine residues in HS chain via 3-O sulfotransferase (3-OST) enzymes, which generates a unique virus-cell fusion receptor during herpes simplex virus (HSV) entry and spread. Emerging evidence now suggests that the unique patterns in HS sulfation assist multiple viruses in invading host cells at various steps of their life cycles. In addition, sulfated-HS structures are known to assist in invading host defense mechanisms and initiating multiple inflammatory processes; a critical event in the disease development. All these processes are detrimental for the host and therefore raise the question of how HS-sulfation is regulated. Epigenetic modulations have been shown to be implicated in these reactions during HSV infection as well as in HS modifying enzyme sulfotransferases, and therefore pose a critical component in answering it. Interestingly, heparanase (HPSE) activity is shown to be upregulated during virus infection and multiple other diseases assisting in virus replication to promote cell and tissue damage. These phenomena suggest that sulfotransferases and HPSE serve as key players in extracellular matrix remodeling and possibly generating unique signatures in a given disease. Therefore, identifying the epigenetic regulation of OST genes, and HPSE resulting in altered yet specific sulfation patterns in HS chain during virus infection, will be a significant a step toward developing potential diagnostic markers and designing novel therapies.

State-of-the-Art Extraction Methodologies for Bioactive Compounds from Algal Biome to Meet Bio-Economy Challenges and Opportunities

Over the years, significant research efforts have been made to extract bioactive compounds by applying different methodologies for various applications. For instance, the use of bioactive compounds in several commercial sectors such as biomedical, pharmaceutical, cosmeceutical, nutraceutical and chemical industries, has promoted the need of the most suitable and standardized methods to extract these bioactive constituents in a sophisticated and cost-effective manner. In practice, several conventional extraction methods have numerous limitations, e.g., lower efficacy, high energy cost, low yield, etc., thus urges for new state-of-the-art extraction methodologies. Thus, the optimization along with the integration of efficient pretreatment strategies followed by traditional extraction and purification processes, have been the primary goal of current research and development studies. Among different sources, algal biome has been found as a promising and feasible source to extract a broader spectrum of bioactive compounds with point-of-care application potentialities. As evident from the literature, algal bio-products includes biofuels, lipids, polyunsaturated fatty acids, pigments, enzymes, polysaccharides, and proteins. The recovery of products from algal biomass is a matter of constant development and progress. This review covers recent advancements in the extraction methodologies such as enzyme-assisted extraction (EAE), supercritical-fluid extraction (SFE), microwave-assisted extraction (MAE) and pressurized-liquid extraction (PLF) along with their working mechanism for extracting bioactive compounds from algal-based sources to meet bio-economy challenges and opportunities. A particular focus has been given to design characteristics, performance evaluation, and point-of-care applications of different bioactive compounds of microalgae. The previous and recent studies on the anticancer, antibacterial, and antiviral potentialities of algal-based bioactive compounds have also been discussed with particular reference to the mechanism underlying the effects of these active constituents with the related pathways. Towards the end, the information is also given on the possible research gaps, future perspectives and concluding remarks.

An attempt to induce an immunomodulatory effect in rowers with spirulina extract

Background

The aim of this study was to analyze the response of selected components of the immune system in rowers to maximal physical exercise, and to verify if this response can be modulated by supplementation with spirulina (cyanobacterium Spirulina platensis).

Method

The double-blind study included 19 members of the Polish Rowing Team. The subjects were randomly assigned to the supplemented group (n = 10), receiving 1500 mg of spirulina extract for 6 weeks, or to the placebo group (n = 9). The participants performed a 2000-m test on a rowing ergometer at the beginning (1st examination) and at the end of the supplementation period (2nd examination). Blood samples were obtained from the antecubital vein prior to each exercise test, 1 min after completing the test, and after a 24-h recovery period. Subpopulations of T regulatory lymphocytes (Tregs) [CD4+/CD25+/CD127-], cytotoxic lymphocytes (CTLs) [CD8+/TCRαβ+], natural killer (NK) cells [CD3-/CD16+/CD56+] and TCRδγ-positive (Tδγ) cells were determined by means of flow cytometry.

Results

On the 2nd examination, athletes from the supplemented group showed neither a post-exercise increase in Treg count nor a post-recovery decrease in Tδγ cell count (both observed in the placebo group), and presented with significantly lower values of Treg/CTL prior to and after the exercise. During the same examination, rowers from the placebo group showed a significant post-recovery increase in Treg/(NK + Tδγ + CTL) ratio, which was absent in the supplemented group.

Conclusion

The results of this study imply that supplementation with spirulina extract may protect athletes against a deficit in immune function (especially, anti-infectious function) associated with strenuous exercise, and may cause a beneficial shift in "overtraining threshold" preventing a radical deterioration of immunity.

Glycans with Antiviral Activity from Marine Organisms

There remains today a critical need for new antiviral agents, particularly in view of the alarming increase in drug resistance and associated issues. The marine environment has been a prolific contributor towards the identification of novel therapeutic agents in the recent few decades. Added to this, glycans (or carbohydrate- or sugar-based compounds) have in very recent decades made outstanding contributions to the development of novel therapeutics. This review brings together these significant facets of modern drug discovery by presenting the reported literature on glycans derived from marine organisms that possess antiviral activity.The glycans have been grouped together based on the marine organism they were isolated from, namely, (1) bacteria, (2) chromists, (3) plants and (4) animals. For chromists, glycans are further subsectioned into Ochrophyta (brown algae), Miozoa (according to www.algaebase.org ; also called Myzozoa according to WoRMS, www.marinespecies.org ) (dinoflagellates) and Bacillariophyta (diatoms). For plants, glycans are further subsectioned into Chlorophyta, Rhodophyta and Tracheophyta. Glycans isolated to date are reported as alginates, chitosan, extracellular polysaccharides, fucans (e.g. fucoidans), galactans (e.g. carrageenans), glycolipids, glycosaminoglycans, glycosides, glycosylated haemocyanin, laminarans, mannans, polysaccharides (not defined), rhamnans and xylomannans. Interestingly, many of the glycans displaying antiviral properties are sulfated.Reports indicate that marine-sourced glycans have exhibited antiviral activity against African swine fever virus, cytomegalovirus, dengue virus, Epstein-Barr virus, encephalomyocarditis virus, human immunodeficiency virus, hepatitis C virus, herpes simplex virus, human cytomegalovirus, human papilloma virus, human rhino virus, influenza virus, Japanese encephalitis virus, murine leukaemia virus, murine sarcoma virus, Newcastle disease virus, parainfluenza virus, respiratory syncytial virus, Semliki Forest virus, tobacco mosaic virus, vaccinia virus, varicella zoster virus, viral haemorrhagic septicaemia virus and vesicular stomatitis virus. Selected representative glycan structures are presented in Fig. 20.1.

The chemical profile and pharmacodynamic properties of extracellular Wollea saccata biopolymer

Microalgae organisms are of interest for many biotechnology applications due to the production of a wide range of biologically active compounds. Incubation of Wollea saccata in a large scale afforded a mucilaginous, high molecular weight biopolymer composed of carbohydrate, protein and phenolic compounds. Sugar moiety was rich in hexoses (60%) and 6-deoxyhexoses (31%), while only 9% of pentoses was identified. Methylation analysis revealed about 40 types of methylated sugar derivatives, suggesting a very complex structure of Wollea biopolymer. Pharmacological studies revealed new pharmacodynamic properties of cyanobacteria biopolymer, i.e. antitussive and bronchodilatory. Biopolymer was able to suppress the cough reflex induced by chemical tussigen, but its effect was lower than that of codeine, the strongest antitussive agent. The bronchodilatory effect was similar or higher than the effect of salbutamol, a bronchodilatory drug used in a clinical practice. In pharmacological studies, there were no signs of toxicity or side effects in the animals following administration of Wollea biopolymer.

Uncovering Potential Applications of Cyanobacteria and Algal Metabolites in Biology, Agriculture and Medicine: Current Status and Future Prospects

Cyanobacteria and algae having complex photosynthetic systems can channelize absorbed solar energy into other forms of energy for production of food and metabolites. In addition, they are promising biocatalysts and can be used in the field of "white biotechnology" for enhancing the sustainable production of food, metabolites, and green energy sources such as biodiesel. In this review, an endeavor has been made to uncover the significance of various metabolites like phenolics, phytoene/terpenoids, phytols, sterols, free fatty acids, photoprotective compounds (MAAs, scytonemin, carotenoids, polysaccharides, halogenated compounds, etc.), phytohormones, cyanotoxins, biocides (algaecides, herbicides, and insecticides) etc. Apart from this, the importance of these metabolites as antibiotics, immunosuppressant, anticancer, antiviral, anti-inflammatory agent has also been discussed. Metabolites obtained from cyanobacteria and algae have several biotechnological, industrial, pharmaceutical, and cosmetic uses which have also been discussed in this review along with the emerging technology of their harvesting for enhancing the production of compounds like bioethanol, biofuel etc. at commercial level. In later sections, we have discussed genetically modified organisms and metabolite production from them. We have also briefly discussed the concept of bioprocessing highlighting the functioning of companies engaged in metabolites production as well as their cost effectiveness and challenges that are being addressed by these companies.

Antioxidant, Immunomodulating, and Microbial-Modulating Activities of the Sustainable and Ecofriendly Spirulina

The highly nutritional and ecofriendly Spirulina (Arthrospira platensis) has hypolipidemic, hypoglycemic, and antihypertensive properties. Spirulina contains functional compounds, such as phenolics, phycocyanins, and polysaccharides, with antioxidant, anti-inflammatory, and immunostimulating effects. Studies conducted on Spirulina suggest that it is safe in healthy subjects, but attitude to eating probably affects the acceptability of Spirulina containing foods. Although the antioxidant effect of Spirulina is confirmed by the intervention studies, the concerted modulation of antioxidant and inflammatory responses, suggested by in vitro and animal studies, requires more confirmation in humans. Spirulina supplements seem to affect more effectively the innate immunity, promoting the activity of natural killer cells. The effects on cytokines and on lymphocytes' proliferation depend on age, gender, and body weight differences. In this context, ageing and obesity are both associated with chronic low grade inflammation, immune impairment, and intestinal dysbiosis. Microbial-modulating activities have been reported in vitro, suggesting that the association of Spirulina and probiotics could represent a new strategy to improve the growth of beneficial intestinal microbiota. Although Spirulina might represent a functional food with potential beneficial effects on human health, the human interventions used only supplements. Therefore, the effect of food containing Spirulina should be evaluated in the future.

Natural remedies for non-steroidal anti-inflammatory drug-induced toxicity

The liver is an important organ of the body, which has a vital role in metabolic functions. The non-steroidal anti-inflammatory drug (NSAID), diclofenac causes hepato-renal toxicity and gastric ulcers. NSAIDs are noted to be an agent for the toxicity of body organs. This review has elaborated various scientific perspectives of the toxicity caused by diclofenac and its mechanistic action in affecting the vital organ. This review suggests natural products are better remedies than current clinical drugs against the toxicity caused by NSAIDs. Natural products are known for their minimal side effects, low cost and availability. On the other hand, synthetic drugs pose the danger of adverse effects if used frequently or over a long period. Copyright © 2016 John Wiley & Sons, Ltd.

Well-tolerated Spirulina extract inhibits influenza virus replication and reduces virus-induced mortality

Influenza is one of the most common human respiratory diseases, and represents a serious public health concern. However, the high mutability of influenza viruses has hampered vaccine development, and resistant strains to existing anti-viral drugs have also emerged. Novel anti-influenza therapies are urgently needed, and in this study, we describe the anti-viral properties of a Spirulina (Arthrospira platensis) cold water extract. Anti-viral effects have previously been reported for extracts and specific substances derived from Spirulina, and here we show that this Spirulina cold water extract has low cellular toxicity, and is well-tolerated in animal models at one dose as high as 5,000 mg/kg, or 3,000 mg/kg/day for 14 successive days. Anti-flu efficacy studies revealed that the Spirulina extract inhibited viral plaque formation in a broad range of influenza viruses, including oseltamivir-resistant strains. Spirulina extract was found to act at an early stage of infection to reduce virus yields in cells and improve survival in influenza-infected mice, with inhibition of influenza hemagglutination identified as one of the mechanisms involved. Together, these results suggest that the cold water extract of Spirulina might serve as a safe and effective therapeutic agent to manage influenza outbreaks, and further clinical investigation may be warranted.

Antitumor activities and immunomodulatory of rice bran polysaccharides and its sulfates in vitro

Polysaccharides purified from rice bran show antitumor activity against tumor cells, yet the mechanism of this action remains poorly understood. To address this issue, our study evaluated the effect of rice bran polysaccharides on mouse melanoma cell line B16, and Raw264.7 macrophages. Rice bran polysaccharides (RBP) failed to inhibit B16 cell growth in vitro. However, Raw264.7 macrophages treated by RBP enhancement of cytotoxic effects. The cytotoxicity was confirmed by the stimulation of nitric oxide (NO) production and tumor necrosis factor-α (TNF-α) secretion on Raw264.7 macrophages in a dose-dependent manner. RBP2, a fraction of RBP, notably enhanced the inhibition of B16 cells and boosted the immunepotentiation effect compared with RBP. To further enhance the inhibition of B16 cell growth, sulfated polysaccharides (SRBP) was derived using the chlorosulfonic acid-pyridine method. SRBP2 was found to suppress B16 cell growth, reduce B16 cell survival and stimulate NO and TNF-α production. However, SRBP2 displayed a cytotoxic effect on Raw264.7 macrophages. These results suggest that the antitumor activity of RBP and RBP2 is mediated mainly through the activation of macrophages. SRBP2 exerts its antitumor activity by inducing apoptosis in tumor cells and the secretion of NO and TNF-α.

Characterization of the inhibitory effect of an extract of Prunella vulgaris on Ebola virus glycoprotein (GP)-mediated virus entry and infection

Currently, no approved antiviral therapeutic is available for treatment or prevention of Ebola virus (EBOV) infection. In this study, we characterized an EBOV-glycoprotein (GP) pseudotyped HIV-1-based vector system in different cell cultures, including human umbilical vein endothelial cells (HUVECs) and human macrophages, for the screening of anti-EBOV-GP agent(s). Based on this system, we demonstrated that an aqueous extract (CHPV) from the Chinese herb Prunella vulgaris displayed a potent inhibitory effect on EBOV-GP pseudotyped virus (EBOV-GP-V)-mediated infection in various cell lines, including HUVEC and macrophage. In addition, our results indicated that CHPV was able to block an eGFP-expressing Zaire ebola virus (eGFP-ZEBOV) infection in VeroE6 cells. The anti-EBOV activity of CHPV was exhibited in a dose-dependent manner. At a 12.5 μg/ml concentration, the CHPV showed a greater than 80% inhibition of EBOV-GP-V and eGFP-EBOV infections. Likewise, our studies suggested that the inhibitory effect of CHPV occurred by binding directly to EBOV-GP-Vs and blocking the early viral events. Interestingly, our results have shown that CHPV was able to enhance the anti-EBOV activity of the monoclonal antibody MAb 2G4 against EBOV-GP. Overall, this study provides evidence that CHPV has anti-EBOV activity and may be developed as a novel antiviral approach against EBOV infection.

Calcium spirulan derived from Spirulina platensis inhibits herpes simplex virus 1 attachment to human keratinocytes and protects against herpes labialis

BACKGROUND

Chronic infections with herpes simplex virus (HSV) type 1 are highly prevalent in populations worldwide and cause recurrent oral lesions in up to 40% of infected subjects.

OBJECTIVE

We investigated the antiviral activity of a defined Spirulina platensis microalga extract and of purified calcium spirulan (Ca-SP), a sulfated polysaccharide contained therein.

METHODS

The inhibitory effects of HSV-1 were assessed by using a plaque reduction assay and quantitative PCR in a susceptible mammalian epithelial cell line and confirmed in human keratinocytes. Time-of-addition and attachment experiments and fluorescence detection of the HSV-1 tegument protein VP16 were used to analyze the mechanism of HSV-1 inhibition. Effects of Ca-SP on Kaposi sarcoma-associated herpesvirus/human herpes virus 8 replication and uptake of the ORF45 tegument protein were tested in human retinal pigment epithelial cells. In an observational trial the prophylactic effects of topically applied Ca-SP were compared with those of systemic and topical nucleoside analogues in 198 volunteers with recurrent herpes labialis receiving permanent lip makeup.

RESULTS

Ca-SP inhibited HSV-1 infection in vitro with a potency at least comparable to that of acyclovir by blocking viral attachment and penetration into host cells. Ca-SP also inhibited entry of Kaposi sarcoma-associated herpesvirus/human herpes virus 8. In the clinical model of herpes exacerbation, the prophylactic effect of a Ca-SP and microalgae extract containing cream was superior to that of acyclovir cream.

CONCLUSION

These data indicate a potential clinical use of Ca-SP containing Spirulina species extract for the prophylactic treatment of herpes labialis and suggest possible activity of Ca-SP against infections caused by other herpesviruses.

Association of heterotrophic bacteria with aggregated Arthrospira platensis exopolysaccharides: implications in the induction of axenic cultures

Inducing an axenic culture of the edible cyanobacterium Arthrospira (Spirulina) platensis using differential filtration alone is never successful; thus, it has been thought that, in non-axenic cultures, a portion of contaminating bacteria is strongly associated with Arthrospira cells. However, examination of the behavior of these bacteria during filtration revealed that they were not associated with Arthrospira cells but with aggregates of exopolysaccharides present in the medium away from the Arthrospira cells. Based on this finding, a rapid and reliable method for preparing axenic trichomes of A. platensis was established. After verifying the axenicity of the resulting trichomes on enriched agar plates, they were individually transferred to fresh sterile medium using a handmade tool, a microtrowel, to produce axenic cultures. With this technique, axenic cultures of various A. platensis strains were successfully produced. The technique described in this study is potentially applicable to a wider range of filamentous cyanobacteria.

Assessment of pharmacokinetic interaction of spirulina with glitazone in a type 2 diabetes rat model

The objective of the current study was to assess the possible pharmacokinetic interactions of spirulina with glitazones in an insulin resistance rat model. Wistar male albino rats were equally divided into five groups: insulin resistant rats+spirulina (500 mg/kg)+pioglitazone (10 mg/kg), insulin resistant rats+pioglitazone (10 mg/kg), insulin resistant rats+spirulina (500 mg/kg)+rosiglitazone (10 mg/kg), insulin resistant rats+rosiglitazone (10 mg/kg), and insulin resistant rats+spirulina (500 mg/kg). Described doses of pioglitazone, rosiglitazone, or spirulina were per orally administered and the plasma drug concentrations were determined. The pharmacokinetic parameters such as Tmax, Cmax, AUC(0-α), t1/2, and Kel were determined by plotting the drug concentration as a function of time. The data observed in this acute study indicated that there was no statistically significant difference in any of the pharmacokinetic parameters (Tmax, Cmax, AUC(0-α), t1/2, and Kel) of glitazones (pioglitazone, rosiglitazone) or spirulina, when they were coadministered. Given the promising results, this study concludes that the coadministration of spirulina does not influence the pharmacokinetics of glitazones in a type 2 diabetes rat model. Further chronic in vivo studies are recommended to assess the real time effect.

Inhibitory effects of dietary Spirulina platensis on UVB-induced skin inflammatory responses and carcinogenesis

Reactive oxygen species produced in response to UVR are important in skin tumor development. We have previously reported that deficiency of the Ogg1 gene, encoding the repair enzyme for 8-oxo-7,8-dihydroguanine (8-oxoG), increases skin tumor incidence in mice upon repetitive UVB exposure and modulation of UVB-induced inflammatory response. Spirulina platensis is used as a human food supplement because it contains abundant nutritional and antioxidant components. Therefore, we investigated the inhibitory effects of S. platensis on UVB-induced skin tumor development in Ogg1 knockout-(KO) mice and the wild-type (WT) counterpart. Dietary S. platensis suppressed tumor induction and development in both genotypes compared with our previous data without S. platensis. Induction of erythema and ear swelling, one of the hallmarks of UVB-induced inflammatory responses, was suppressed in the skin of Ogg1-KO mice and albino hairless mice fed with dietary S. platensis. Compared with untreated mice, S. platensis-administered mice showed significantly reduced 8-oxoG formation in the skin after UVB exposure. Moreover, we found that S. platensis effectively downregulated the signal proteins p38 mitogen-activated protein kinase, stress-activated protein kinase/c-Jun N-terminal kinase, and extracellular signal-regulated kinase after UVB exposure especially in Ogg1-KO mice. Our results suggest that S. platensis exerts antitumor effects against UVB irradiation in the skin through its anti-inflammatory and antioxidant effects.

Highly valuable microalgae: biochemical and topological aspects

The past decade has seen a surge in the interest in microalgae culture for biodiesel production and other applications as renewable biofuels as an alternative to petroleum transport fuels. The development of new technologies for the culture of these photosynthetic microorganisms and improved knowledge of their biochemical composition has spurred innovation in the field of high-value biomolecules. These developments are only economically viable if all the microalgae fractions are valorized in a biorefinery strategy. Achieving this objective requires an understanding of microalgae content and the cellular localization of the main biomolecular families in order to develop efficient harvest and sequential recovery technologies. This review summarizes the state of the art in microalgae compositions and topologies using some examples of the main industrially farmed microalgae.

Bioactivity and applications of sulphated polysaccharides from marine microalgae

Marine microalgae have been used for a long time as food for humans, such as Arthrospira (formerly, Spirulina), and for animals in aquaculture. The biomass of these microalgae and the compounds they produce have been shown to possess several biological applications with numerous health benefits. The present review puts up-to-date the research on the biological activities and applications of polysaccharides, active biocompounds synthesized by marine unicellular algae, which are, most of the times, released into the surrounding medium (exo- or extracellular polysaccharides, EPS). It goes through the most studied activities of sulphated polysaccharides (sPS) or their derivatives, but also highlights lesser known applications as hypolipidaemic or hypoglycaemic, or as biolubricant agents and drag-reducers. Therefore, the great potentials of sPS from marine microalgae to be used as nutraceuticals, therapeutic agents, cosmetics, or in other areas, such as engineering, are approached in this review.

Systems biology and metabolic engineering of Arthrospira cell factories

Arthrospira are attractive candidates to serve as cell factories for production of many valuable compounds useful for food, feed, fuel and pharmaceutical industries. In connection with the development of sustainable bioprocessing, it is a challenge to design and develop efficient Arthrospira cell factories which can certify effective conversion from the raw materials (i.e. CO₂ and sun light) into desired products. With the current availability of the genome sequences and metabolic models of Arthrospira, the development of Arthrospira factories can now be accelerated by means of systems biology and the metabolic engineering approach. Here, we review recent research involving the use of Arthrospira cell factories for industrial applications, as well as the exploitation of systems biology and the metabolic engineering approach for studying Arthrospira. The current status of genomics and proteomics through the development of the genome-scale metabolic model of Arthrospira, as well as the use of mathematical modeling to simulate the phenotypes resulting from the different metabolic engineering strategies are discussed. At the end, the perspective and future direction on Arthrospira cell factories for industrial biotechnology are presented.

Two-stage culture method for optimized polysaccharide production in Spirulina platensis

BACKGROUND

The polysaccharides of Spirulina platensis possess many biological functions. Reproducing the conditions under which S. platensis produces polysaccharides is critical to furthering our understanding of the function of these polysaccharides for commercial mass production. The changes in microalgal polysaccharide production were studied under greenhouse and laboratory conditions using varying light intensities, temperatures, and NaCl concentrations.

RESULTS

The polysaccharide yield was positively correlated with culturing under 192 µmol photons m(-2) s(-1) light intensity at 38 °C or in 0.75 mol L(-1) NaCl. However, NaCl reduced the total biomass productivity of S. platensis. To mitigate the negative effects of environmental stress on maximal polysaccharide production, we proposed a two-stage culture method. The first stage, designed to increase biomass production, involved culturing under 96 µmol photons m(-2) s(-1) light intensity at 28 °C. Following this, on achieving maximum biomass production, the second stage, designed to stimulate polysaccharide production, involved culturing under 192 µmol photons m(-2) s(-1) light intensity at 38 °C for 3 days or in a 0.75 mol L(-1) NaCl medium for 2 days. High-performance liquid chromatographic analysis revealed that S. platensis polysaccharides were composed of various monosaccharides, including glucose, galactose, rhamnose, mannose, fructose, and mannitol.

CONCLUSION

The two-stage culture can be successfully applied to achieve the goal of polysaccharide mass production. The first stage focuses on rapidly increasing microalgal biomass. The second stage of culture conditions requires modification to maximize polysaccharide yield.

Spirulina platensis versus silymarin in the treatment of chronic hepatitis C virus infection. A pilot randomized, comparative clinical trial

Background

Spirulina platensis, a cynobacterium used frequently as a dietary supplement had been found to exhibit many immune-stimulating and antiviral activities. It had been found to activate macrophages, NK cells, T cells, B cells, and to stimulate the production of Interferon gamma (IFN-γ) and other cytokines. Natural substances isolated from Spirulina platensis had been found to be potent inhibitors against several enveloped viruses by blocking viral absorption/penetration and some replication stages of progeny viruses after penetration into cells. We aimed to study whether this dietary supplement possesses any therapeutically feasible activity worthy of further larger controlled clinical evaluation.

Methods

Sixty six patients with chronic hepatitis C virus infection and eligible for inclusion had been randomized to either Spirulina or Silymarin treated groups for a period of six months treatment.

The two groups were followed up and blindly compared for early (after 3 months) and end of 6 months treatment virological response. The effects of both treatments on each of alanine aminotransferase (ALT), Chronic Liver Disease Questionnaire scores (CLDQ), Arizona Sexual Experience Scale scores (ASEX) and the occurrence of any attributable adverse events were also compared.

Results

Among the 30 patients who had been treated with Spirulina and completed the 6 months protocol, 4 patients (13.3%) had a complete end of treatment virological response and 2 patients (6.7%) had a partial end of treatment response defined as significant decrease of virus load of at least 2-logs₁₀. Though the proportion of responders in Spirulina group was greater than in the Silymarin group, the difference was not statistically significant at the end of both 6 months (p = 0.12) and 3 months treatment (p = 0.22) by Exact test. Alanine aminotransferase as well as CLDQ and ASEX scores were found to be more significantly improved in Spirulina than in Silymarin treated group.

Conclusions

Our results could suggest a therapeutically feasible potential for Spirulina platensis in chronic HCV patients, worthy to conduct a larger sized and longer study to confirm these safety and efficacy encouraging results.

Trial Registration

WHO Clinical Trial Registration ID: ACTRN12610000958088

http://apps.who.int/trialsearch/trial.aspx?trialid=ACTRN12610000958088

Sequence similarity between the erythrocyte binding domain of the Plasmodium vivax Duffy binding protein and the V3 loop of HIV-1 strain MN reveals a functional heparin binding motif involved in binding to the Duffy antigen receptor for chemokines

Background

The HIV surface glycoprotein gp120 (SU, gp120) and the Plasmodium vivax Duffy binding protein (PvDBP) bind to chemokine receptors during infection and have a site of amino acid sequence similarity in their binding domains that often includes a heparin binding motif (HBM). Infection by either pathogen has been found to be inhibited by polyanions.

Results

Specific polyanions that inhibit HIV infection and bind to the V3 loop of X4 strains also inhibited DBP-mediated infection of erythrocytes and DBP binding to the Duffy Antigen Receptor for Chemokines (DARC). A peptide including the HBM of PvDBP had similar affinity for heparin as RANTES and V3 loop peptides, and could be specifically inhibited from heparin binding by the same polyanions that inhibit DBP binding to DARC. However, some V3 peptides can competitively inhibit RANTES binding to heparin, but not the PvDBP HBM peptide. Three other members of the DBP family have an HBM sequence that is necessary for erythrocyte binding, however only the protein which binds to DARC, the P. knowlesi alpha protein, is inhibited by heparin from binding to erythrocytes. Heparitinase digestion does not affect the binding of DBP to erythrocytes.

Conclusion

The HBMs of DBPs that bind to DARC have similar heparin binding affinities as some V3 loop peptides and chemokines, are responsible for specific sulfated polysaccharide inhibition of parasite binding and invasion of red blood cells, and are more likely to bind to negative charges on the receptor than cell surface glycosaminoglycans.

Halomonas stenophila sp. nov., a halophilic bacterium that produces sulphate exopolysaccharides with biological activity

We have undertaken a polyphasic taxonomic study of two halophilic, Gram-negative bacterial strains, N12T and B-100, that produce sulphated exopolysaccharides with biological activity. They were isolated from two different saline soil samples. Both strains grow at NaCl concentrations within the range 3–15 % (w/v) [optimum 5–10 % (w/v)], at 15–37 °C (optimum 20–32 °C) and at pH 6–8 (optimum pH 7–8). Their 16S rRNA gene sequences indicate that they belong to the genus Halomonas in the class Gammaproteobacteria. Their closest relative is Halomonas nitroreducens, to which our strains show maximum 16S rRNA gene sequence similarity values of 98.7 % (N12T) and 98.3 % (B-100). Their DNA G+C contents are 61.9 and 63.8 mol%, respectively. The results of DNA–DNA hybridizations showed 43.9 % relatedness between strain N12T and H. nitroreducens CECT 7281T, 30.5 % between N12T and Halomonas ventosae CECT 5797T, 39.2 % between N12T and Halomonas fontilapidosi CECT 7341T, 46.3 % between N12T and Halomonas maura CECT 5298T, 52.9 % between N12T and Halomonas saccharevitans LMG 23976T, 51.3 % between N12T and Halomonas koreensis JCM 12237T and 100 % between strains N12T and B-100. The major fatty acids of strain N12T are C12 : 0 3-OH (5.42 %), C15 : 0 iso 2-OH/C16 : 1ω7c (17.37 %), C16 : 0 (21.62 %) and C18 : 1ω7c (49.19 %). The proposed name for the novel species is Halomonas stenophila sp. nov. Strain N12T ( = CECT 7744T  = LMG 25812T) is the type strain.

Potential of Spirulina Platensis as a Nutritional Supplement in Malnourished HIV-Infected Adults in Sub-Saharan Africa: A Randomised, Single-Blind Study

BACKGROUND

Malnutrition is a major global public health issue and its impact on communities and individuals is more dramatic in Sub-Saharan Africa, where it is compounded by widespread poverty and generalized high prevalence of human immunodeficiency virus (HIV). Therefore, malnutrition should be addressed through a multisectorial approach, and malnourished individuals should have access to nutritional rehabilitation molecules that are affordable, accessible, rich in nutrient and efficient. We thus assessed the efficacy of two affordable and accessible nutritional supplements, spirulina platensis versus soya beans among malnourished HIV-infected adults.

METHODS

Undernourished patients, naïve of, but eligible to antiretroviral treatment (ART), aged 18 to 35 years were enrolled and randomly assigned to two groups. The first group received spirulina (Group A) as food supplement and the second received soya beans (Group B). Patients were initiated ART simultaneously with supplements. Food supplements were auto-administered daily, the quantity being calculated according to weight to provide 1.5 g/kg body weight of proteins with 25% from supplements (spirulina and soya beans). Patients were monitored at baseline and followed-up during twelve weeks for anthropometric parameters, body composition, haemoglobin and serum albumin, CD4 count and viral load.

RESULTS

Fifty-two patients were enrolled (Group A: 26 and Group B: 26). The mean age was 26.4 ± 4.9 years (Group A) and 28.7 ± 4.8 (Group B) with no significant difference between groups (P = 0.10). After 12 weeks, weight and BMI significantly improved in both groups (P < 0.001 within each group). The mean gain in weight and BMI in Group A and B were 4.8 vs. 6.5 kg, (P = 0.68) and 1.3 vs. 1.90 Kg/m(2), (P = 0.82) respectively. In terms of body composition, fat free mass (FFM) did not significantly increase within each group (40.5 vs. 42.2 Kg, P = 0.56 for Group A; 39.2 vs. 39.0 Kg, P = 0.22 for Group B). But when compared between the two groups at the end of the trial, FFM was significantly higher in the spirulina group (42.2 vs. 39.0 Kg, P = 0.01). The haemoglobin level rose significantly within groups (P < 0.001 for each group) with no difference between groups (P = 0.77). Serum albumin level did not increase significantly within groups (P < 0.90 vs. P < 0.82) with no difference between groups (P = 0.39). The increase in CD4 cell count within groups was significant (P < 0.01 in both groups), with a significantly higher CD4 count in the spirulina group compared to subjects on soya beans at the end of the study (P = 0.02). Within each group, HIV viral load significantly reduced at the end of the study (P < 0.001 and P = 0.04 for spirulina and soya beans groups respectively). Between the groups, the viral load was similar at baseline but significantly reduced in the spirulina group at the end of the study (P = 0.02).

CONCLUSION

We therefore conclude in this preliminary study, firstly, that both spirulina and soja improve on nutritional status of malnourished HIV-infected patients but in terms of quality of nutritional improvement, subjects on spirulina were better off than subjects on soya beans. Secondly, nutritional rehabilitation improves on immune status with a consequent drop in viral load but further investigations on the antiviral effects of this alga and its clinical implications are strongly needed.

Early inhibitors of human cytomegalovirus: state-of-art and therapeutic perspectives

Human cytomegalovirus (HCMV) infection is associated with severe morbidity and mortality in immunocompromised individuals, mainly transplant recipients and AIDS patients, and is the most frequent cause of congenital malformations in newborn children. To date, few drugs are licensed for the treatment of HCMV infections, most of which target the viral DNA polymerase and suffer from many drawbacks, including long-term toxicity, low potency, and poor bioavailability. In addition, the emergence of drug-resistant viral strains is becoming an increasing problem for disease management. Finally, none of the current anti-HCMV drugs have been approved for the treatment of congenital infections. For all these reasons, there is still a strong need for new anti-HCMV drugs with novel mechanisms of action. The first events of the virus replication cycle, including attachment, entry, immediate-early gene expression, and immediate-early functions—in particular that of Immediate-Early 2 protein—represent attractive targets for the development of novel antiviral compounds. Such inhibitors would block not only the expression of viral immediate-early proteins, which play a key role in the pathogenesis of HCMV infection, but also the host immunomodulation and the changes to cell physiology induced by the first events of virus infection. This review describes the current knowledge on the initial phases of HCMV replication, their validation as potential novel antiviral targets, and the development of compounds that block such processes.

Anti pseudorabies virus activity of kumazasa extract

Sasa veitchii or "kumazasa" has been used for the preservation of food, or preventing bacterial activity. However, the antiviral activity of kumazasa is poorly understood. In the present study, the antiviral activity of kumazasa extract (KE) was assessed by the plaque reduction assay for the pseudorabies virus (PRV). KE reduced 99% of the plaque formation of PRV at concentrations of 1.2%, showing that KE inhibited PRV adsorption to cells and IE180 expression. The polysaccharide fraction of KE showed a concentration dependent inhibition of PRV plaque formation. We conclude that KE possesses potent anti PRV activity, and the candidate responsible for the antiviral property was the polysaccharide fraction.

Sulfated polysaccharides in marine sponges: extraction methods and anti-HIV activity

The extraction, fractionation and HIV-1 inhibition potential of polysaccharides extracted from three species of marine sponges, Erylus discophorus, Cliona celata and Stelletta sp., collected in the Northeastern Atlantic, is presented in this work. The anti-HIV activity of 23 polysaccharide pellets and three crude extracts was tested. Crude extracts prepared from Erylus discophorus specimens were all highly active against HIV-1 (90 to 95% inhibition). Cliona celata pellets showed low polysaccharide content (bellow 38.5%) and almost no anti-HIV activity (<10% inhibition). Stelletta sp. pellets, although quite rich in polysaccharide (up to 97.3%), showed only modest bioactivity (<36% HIV-1 inhibition). Erylus discophorus pellets were among the richest in terms of polysaccharide content (up to 98%) and the most active against HIV-1 (up to 95% inhibition). Chromatographic fractionation of the polysaccharide pellet obtained from a specimen of Erylus discophorus (B161) yielded only modestly active fractions. However, we could infer that the active molecule is most probably a high molecular weight sulfated polysaccharide (>2000 kDa), whose mechanism is possibly preventing viral attachment and entry (fusion inhibitor).