In vitro antioxidant activities of sulfated polysaccharide fractions extracted from Corallina officinalis

Comparative metabolomics study on the secondary metabolites of the red alga, Corallina officinalis and its associated endosymbiotic fungi

Marine endosymbionts have gained remarkable interest in the last three decades in terms of natural products (NPs) isolated thereof, emphasizing the chemical correlations with those isolated from the host marine organism. The current study aimed to conduct comparative metabolic profiling of the marine red algae Corallina officinalis, and three fungal endosymbionts isolated from its inner tissues namely, Aspergillus nidulans, A. flavipes and A. flavus. The ethyl acetate (EtOAc) extracts of the host organism as well as the isolated endosymbionts were analyzed using ultra-high performance liquid chromatography coupled to high resolution tandem mass spectrometry (UHPLC-MS/MS)in both positive and negative ion modes, applying both full scan (FS) and all ion fragmentation (AIF) modes. Extensive interpretation of the LC-MS/MS spectra had led to the identification of 76 metabolites belonging to different phytochemical classes including alkaloids, polyketides, sesquiterpenes, butyrolactones, peptides, fatty acids, isocoumarins, quinones, among others. Metabolites were tentatively identified by comparing the accurate mass and fragmentation pattern with metabolites previously reported in the literature, as well as bioinformatics analysis using GNPS. A relationship between the host C. officinalis and its endophytes (A. flavus, A. nidulans, and A. flavipes) was discovered. C. officinalis shares common metabolites with at least one of the three endosymbiotic fungi. Some metabolites have been identified in endophytes and do not exist in their host. Multivariate analysis (MVA) revealed discrimination of A. flavipes from Corallina officinalis and other associated endophytic Aspergillus fungi (A. flavus and A. nidulans).

Physiochemical changes, metabolite discrepancies of brown seaweed-derived sulphated polysaccharides in the upper gastrointestinal tract and their effects on bioactive expression

Brown seaweed-derived polysaccharides, notably fucoidan and laminarin, are known for their extensive array of bioactivities and physicochemical properties. However, the effects of upper digestive tract modification on the bioactive performance of fucoidan and laminarin fractions (FLFs) sourced from Australian native species are largely unknown. Here, the digestibility and bioaccessibility of FLFs were evaluated by tracking the dynamic changes in reducing sugar content (CR), profiling the free monosaccharide composition using LC-MS, and comparing high-performance gel permeation chromatography profile variation via LC-SEC-RI. The effects of digestive progression on bioactive performance were assessed by comparing the antioxidant and antidiabetic potential of FLFs and FLF digesta. We observed that molecular weight (Mw) decreased during gastric digestion indicating that FLF aggregates were disrupted in the stomach. During intestinal digestion, Mw gradually decreased and CR increased indicating cleavage of glycosidic bonds releasing free sugars. Although the antioxidant and antidiabetic capacities were not eliminated by the digestion progression, the bioactive performance of FLFs under a digestive environment was reduced contrasting with the same concentration level of the undigested FLFs. These data provide comprehensive information on the digestibility and bioaccessibility of FLFs, and shed light on the effects of digestive progression on bioactive expression.

Selenosugar, selenopolysaccharide, and putative selenoflavonoid in plants

Selenium (Se) is a naturally occurring essential micronutrient that is required for human health. Selenium supports cellular antioxidant defense and possesses bioeffects such as anti-inflammation, anti-cancer, anti-diabetic, and cardiovascular and liver protective effects arising from Se-enhanced cellular antioxidant activity. Past studies on Se have focused on elucidating Se speciation in foods, biofortification strategies to produce Se-enriched foods to address Se deficiency in the population, and the biochemical activities of Se in health. The bioavailability and toxicity of Se are closely correlated to its chemical forms and may exhibit varying effects on body physiology. Selenium exists in inorganic and organic forms, in which inorganic Se such as sodium selenite and sodium selenate is more widely available. However, it is a challenge for safe and effective supplementation considering inorganic Se low bioavailability and high cytotoxicity. Organic Se, by contrast, exhibits higher bioavailability and lower toxicity and has a more diverse composition and structure. Organic Se exists as selenoamino acids and selenoproteins, but recent research has provided evidence that it also exists as selenosugars, selenopolysaccharides, and possibly as selenoflavonoids. Different food categories contain various Se compounds, and their Se profiles vary significantly. Therefore, it is necessary to delineate Se speciation in foods to understand their impact on health. This comprehensive review documents our knowledge of the recent uncovering of the existence of selenosugars and selenopolysaccharides and the putative evidence for selenoflavonoids. The bioavailability and bioactivities of these food-derived organic Se compounds are highlighted, in addition to their composition, structural features, and structure-activity relationships.

The molecular mechanism of polysaccharides in combating major depressive disorder: A comprehensive review

Major depressive disorder (MDD) is a complex psychiatric condition with diverse etiological factors. Typical pathological features include decreased cerebral cortex, subcortical structures, and grey matter volumes, as well as monoamine transmitter dysregulation. Although medications exist to treat MDD, unmet needs persist due to limited efficacy, induced side effects, and relapse upon drug withdrawal. Polysaccharides offer promising new therapies for MDD, demonstrating antidepressant effects with minimal side effects and multiple targets. These include neurotransmitter, neurotrophin, neuroinflammation, hypothalamic-pituitary-adrenal axis, mitochondrial function, oxidative stress, and intestinal flora regulation. This review explores the latest advancements in understanding the pharmacological actions and mechanisms of polysaccharides in treating major depression. We discuss the impact of polysaccharides' diverse structures and properties on their pharmacological actions, aiming to inspire new research directions and facilitate the discovery of novel anti-depressive drugs.

Sulfated polysaccharides from Caulerpa lentillifera: Optimizing the process of extraction, structural characteristics, antioxidant capabilities, and anti-glycation properties

The polysaccharides found in Caulerpa lentillifera (sea grape algae) are potentially an important bioactive resource. This study makes use of RSM (response surface methodology) to determine the optimal conditions for the extraction of valuable SGP (sea grape polysaccharides). The findings indicated that a water/raw material ratio of 10:1 mL/g, temperature of 90 °C, and extraction time of 45 min would maximize the yield, with experimentation achieving a yield of 21.576 %. After undergoing purification through DEAE-52 cellulose and Sephacryl S-100 column chromatography, three distinct fractions were obtained, namely SGP11, SGP21, and SGP31, each possessing average molecular weights of 38.24 kDa, 30.13 kDa, and 30.65 kDa, respectively. Following characterization, the fractions were shown to comprise glucose, galacturonic acid, xylose, and mannose, while the sulfate content was in the range of 12.2-21.8 %. Using Fourier transform infrared spectroscopy (FT-IR) it was possible to confirm with absolute certainty the sulfate polysaccharide attributes of SGP11, SGP21, and SGP31. NMR (nuclear magnetic resonance) findings made it clear that SGP11 exhibited α-glycosidic configurations, while the configurations of SGP21 and SGP31 were instead β-glycosidic. The in vitro antioxidant assays which were conducted revealed that each of the fractions was able to demonstrate detectable scavenging activity against 1,1-diphenyl-2-picrylhydrazyl (DPPH) radicals and 2,2'-azino-bis (3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) radical cations. All fractions were also found to exhibit the capacity to scavenge NO radicals in a dose-dependent manner. SGP11, SGP21, and SGP31 were also able to display cellular antioxidant activity (CAA) against the human adenocarcinoma colon (Caco-2) cell line when oxidative damage was induced. The concentration levels were found to govern the extent of such activity. Moreover, purified SGP were found to exert strong inhibitory effects upon glycation, with the responses dependent upon dosage, thus confirming the potential for SGP to find a role as a natural resource for the production of polysaccharide-based antioxidant drugs, or products to promote improved health.

Mycelial biomass and intracellular polysaccharides production, characterization, and activities in Auricularia auricula-judae cultured with different carbon sources

The carbon source, an essential factor for submerged culture, affects fungal polysaccharides production, structures, and activities. This study investigated the impact of carbon sources, including glucose, fructose, sucrose, and mannose, on mycelial biomass and the production, structural characterization, and bioactivities of intracellular polysaccharides (IPS) produced by submerged culture of Auricularia auricula-judae. Results showed that mycelial biomass and IPS production varied with different carbon sources, where using glucose as the carbon source produced the highest mycelial biomass (17.22 ± 0.29 g/L) and IPS (1.62 ± 0.04 g/L). Additionally, carbon sources were found to affect the molecular weight (Mw) distributions, monosaccharide compositions, structural characterization, and activities of IPSs. IPS produced with glucose as the carbon source exhibited the best in vitro antioxidant activities and had the strongest protection against alloxan-damaged islet cells. Correlation analysis revealed that Mw correlated positively with mycelial biomass (r = 0.97) and IPS yield (r = 1.00), while IPS antioxidant activities correlated positively with Mw and negatively with mannose content; the protective activity of IPS was positively related to its reducing power. These findings indicate a critical structure-function relationship for IPS and lay the foundation for utilizing liquid-fermented A. aruicula-judae mycelia and the IPS in functional food production.

Biochemical Characteristics and Potential Biomedical Applications of Hydrolyzed Carrageenans

Seaweed contains a variety of bioactive compounds; the most abundant of them are polysaccharides, which have significant biological and chemical importance. Although algal polysaccharides, especially the sulfated polysaccharides, have great potential in the pharmaceutical, medical and cosmeceutical sectors, the large molecular size often limits their industrial applications. The current study aims to determine the bioactivities of degraded red algal polysaccharides by several in vitro experiments. The molecular weight was determined by size-exclusion chromatography (SEC), and the structure was confirmed by FTIR and NMR. In comparison to the original furcellaran, the furcellaran with lower molecular weight had higher OH scavenging activities. The reduction in molecular weight of the sulfated polysaccharides resulted in a significant decrease in anticoagulant activities. Tyrosinase inhibition improved 2.5 times for hydrolyzed furcellaran. The alamarBlue assay was used to determine the effects of different Mw of furcellaran, κ-carrageenan and ι-carrageenan on the cell viability of RAW264.7, HDF and HaCaT cell lines. It was found that hydrolyzed κ-carrageenan and ι-carrageenan enhanced cell proliferation and improved wound healing, whereas hydrolyzed furcellaran did not affect cell proliferation in any of the cell lines. Nitric oxide (NO) production decreased sequentially as the Mw of the polysaccharides decreased, which indicates that hydrolyzed κ-Carrageenan, ι-carrageenan and furcellaran have the potential to treat inflammatory disease. These findings suggested that the bioactivities of polysaccharides were highly dependent on their Mw, and the hydrolyzed carrageenans could be used in new drug development as well as cosmeceutical applications.

Protective Effect of Tunisian Red Seaweed (Corallina officinalis) Against Bleomycin-Induced Pulmonary Fibrosis and Oxidative Stress in Rats

Idiopathic pulmonary fibrosis is a chronic and progressive respiratory disease whose diagnosis and physiopathogenesis are still poorly understood and for which, until recently, there were no effective treatments. Over the past few decades, many studies have demonstrated that marine macroalgae such as red seaweeds are potential alternative sources of useful bioactive compounds possessing various physiological and biological activities. The present study was aimed to investigate the effect of Corallina officinalis aqueous extract (COAE) against bleomycin (BLM)-induced lung fibrosis in rat. Thus, Wistar rats were divided into 4 groups of 10 each: control, BLM (2 mg/kg), BLM/COAE-150 mg/kg and BLM/COAE-300 mg/kg once a day for 21 days. Obtained results showed that COAE is rich in phenolic compounds and exhibited relatively high antioxidant activity. COAE might significantly reduce the damage caused by BLM by rewarding the decline in weight and pulmonary index in rats given only BLM. Moreover, lungs, liver and kidneys lipid peroxidation, and sulfhydryl group levels were reversed significantly in a dose-dependent manner in the COAE-treated groups. BLM decreased superoxide dismutase (SOD) and catalase (CAT) activities, while COAE administration increased the antioxidant enzyme activities. Histopathologically, COAE attenuates the severity of the inflammatory lungs state caused by instillation of BLM in rats. These findings suggest that COAE can be a potential therapeutic candidate against BLM-induced lung fibrosis.

The variation on structure and immunomodulatory activity of polysaccharide during the longan pulp fermentation

In the current study, the effects of fermentation manners on the structure and immunomodulatory activity of polysaccharide in longan wine or vinegar were investigated. Compared to longan polysaccharide (CP1), polysaccharide in longan wine (CP2) or vinegar (CP3 and CP4) had smaller molecular weights, and was consisted of more mannose, arabinose, rhamnose, galactose and less glucose. After purification, the major fraction (P1-P4) was obtained from CP1-CP4, respectively. The structures and immunoregulatory activities of P1-P4 were characterized. Fermentation and purification were favorable to increase the immunoregulatory activities of P2-P4, which were contributed to their different structural features. The structure-activity relationship analysis indicated that molecular weight, mannose, rhamnose, glucuronic acid, glucose and arabinose were significantly associated with the cytokines secretion. Compared with other polysaccharides, P3 displayed better immunomodulatory activity due to its lower molecular weight, lower contents of rhamnose and glucose, and higher levels of mannose and arabinose by activating MAPK and PI3K/Akt signaling pathways.

Structural Characterization and Rheological and Antioxidant Properties of Novel Polysaccharide from Calcareous Red Seaweed

A novel sulfated xylogalactan (JASX) was extracted and purified from the rhodophyceae Jania adhaerens. JASX was characterized by chromatography (GC/MS-EI and SEC/MALLS) and spectroscopy (ATR-FTIR and ¹H/¹³C NMR) techniques. Results showed that JASX was constituted by repeating units of (→3)-β-d-Galp-(1,4)-3,6-α-l-AnGalp-(1→)_n and (→3)-β-d-Galp-(1,4)-α-l-Galp-(1→)_n substituted on O-2 and O-3 of the α-(1,4)-l-Galp units by methoxy and/or sulfate groups but also on O-6 of the β-(1,3)-d-Galp mainly by β-xylosyl side chains and less by methoxy and/or sulfate groups. The M_w, M_n, Đ, [η] and C* of JASX were respectively 600 and 160 kDa, 3.7, 102 mL.g⁻¹ and 7.0 g.L⁻¹. JASX exhibited pseudoplastic behavior influenced by temperature and monovalent salts and highly correlated to the power-law model and the Arrhenius relationship. JASX presented thixotropic characteristics, a gel-like viscoelastic behavior and a great viscoelasticity character. JASX showed important antioxidant activities, outlining its potential as a natural additive to produce functional foods.

In Silico Screening of Bioactive Compounds of Representative Seaweeds to Inhibit SARS-CoV-2 ACE2-Bound Omicron B.1.1.529 Spike Protein Trimer

Omicron is an emerging SARS-CoV-2 variant, evolved from the Indian delta variant B.1.617.2, which is currently infecting worldwide. The spike glycoprotein, an important molecule in the pathogenesis and transmissions of SARS-CoV-2 variants, especially omicron B.1.1.529, shows 37 mutations distributed over the trimeric protein domains. Notably, fifteen of these mutations reside in the receptor-binding domain of the spike glycoprotein, which may alter transmissibility and infectivity. Additionally, the omicron spike evades neutralization more efficiently than the delta spike. Most of the therapeutic antibodies are ineffective against the omicron variant, and double immunization with BioNTech-Pfizer (BNT162b2) might not adequately protect against severe disease induced by omicron B.1.1.529. So far, no efficient antiviral drugs are available against omicron. The present study identified the promising inhibitors from seaweed’s bioactive compounds to inhibit the omicron variant B.1.1.529. We have also compared the seaweed’s compounds with the standard drugs ceftriaxone and cefuroxime, which were suggested as beneficial antiviral drugs in COVID-19 treatment. Our molecular docking analysis revealed that caffeic acid hexoside (−6.4 kcal/mol; RMSD = 2.382 Å) and phloretin (−6.3 kcal/mol; RMSD = 0.061 Å) from Sargassum wightii (S. wightii) showed the inhibitory effect against the crucial residues ASN417, SER496, TYR501, and HIS505, which are supported for the inviolable omicron and angiotensin-converting enzyme II (ACE2) receptor interaction. Cholestan-3-ol, 2-methylene-, (3beta, 5 alpha) (CMBA) (−6.0 kcal/mol; RMSD = 3.074 Å) from Corallina officinalis (C. officinalis) manifested the strong inhibitory effect against the omicron RBD mutated residues LEU452 and ALA484, was magnificently observed as the essential residues in Indian delta variant B.1.617.2 previously. The standard drugs (ceftriaxone and cefuroxime) showed no or less inhibitory effect against RBD of omicron B.1.1.529. The present study also emphasized the pharmacological properties of the considered chemical compounds. The results could be used to develop potent seaweed-based antiviral drugs and/or dietary supplements to treat omicron B.1.1529-infected patients.

Recent Advancements and Future Perspectives of Microalgae-Derived Pharmaceuticals

Microalgal cells serve as solar-powered factories that produce pharmaceuticals, recombinant proteins (vaccines and drugs), and valuable natural byproducts that possess medicinal properties. The main advantages of microalgae as cell factories can be summarized as follows: they are fueled by photosynthesis, are carbon dioxide-neutral, have rapid growth rates, are robust, have low-cost cultivation, are easily scalable, pose no risk of human pathogenic contamination, and their valuable natural byproducts can be further processed. Despite their potential, there are many technical hurdles that need to be overcome before the commercial production of microalgal pharmaceuticals, and extensive studies regarding their impact on human health must still be conducted and the results evaluated. Clearly, much work remains to be done before microalgae can be used in the large-scale commercial production of pharmaceuticals. This review focuses on recent advancements in microalgal biotechnology and its future perspectives.

Molecular Mechanisms Underlying the Anti-Breast Cancer Stem Cell Activity of Pterocladia capillacea and Corallina officinalis Polysaccharides

OBJECTIVE

This study aimed to appraise the activity of Pterocladia capillacea and Corallina officinalis polysaccharides against breast cancer stem cells (BCSCs). P. capillacea and C. officinalis polysaccharides were characterized to be sulfated polysaccharide-protein complexes.

METHODS

Cytotoxicity of the polysaccharides against MDA-MB-231 and MCF-7 cell lines along with their impact on CD44+/CD24- and aldehyde dehydrogenase 1(ALDH1) positive BCSC population were determined. Their effect on gene expression of CSC markers, Wnt/β-catenin and Notch signaling pathways was evaluated.

RESULTS

P. capillacea and C. officinalis polysaccharides inhibited the growth of breast cancer cells and reduced BCSC subpopulation. P. capillacea polysaccharides significantly down-regulated OCT4, SOX2, ALDH1A3 and vimentin in MDA-MB-231 as well as in MCF-7 cells except for vimentin that was up-regulated in MCF-7 cells. C. officinalis polysaccharides exhibited similar effects except for OCT4 that was up-regulated in MDA-MB-231 cells. Significant suppression of Cyclin D1 gene expression was noted in MDA-MB-231 and MCF-7 cells treated with P. capillacea or C. officinalis polysaccharides. β-catenin and c-Myc genes were significantly down-regulated in MDA-MB-231 cells treated with C. officinalis and P. capillacea polysaccharides, respectively, while being up-regulated in MCF-7 cells treated with either of them. Additionally, P. capillacea and C. officinalis polysaccharides significantly down-regulated Hes1 gene in MCF-7 cells despite increasing Notch1 gene expression level. However, significant down-regulation of Notch1 gene was observed in MDA-MB-231 cells treated with P. capillacea polysaccharides.

CONCLUSION

Collectively, this study provides evidence for the effectiveness of P. capillacea and C. officinalis polysaccharides in targeting BCSCs through interfering with substantial signaling pathways contributing to their functionality.

Extraction and purification of total flavonoids from Eupatorium lindleyanum DC. and evaluation of their antioxidant and enzyme inhibitory activities

The health benefits and promising medical treatment potential of total flavonoids from Eupatorium lindleyanum DC. (TFELDC) have been recognized. The process parameters of extracting total flavonoids from Eupatorium lindleyanum DC. by ultrasonic-microwave synergistic extraction (UMSE) were optimized, and they were purified by AB-8 macroporous resin in the current study. In addition, the antioxidant and enzyme inhibitory activities of the purified TFELDC (PTFELDC) were evaluated. The results showed that the optimal parameters of UMSE were as follows: ethanol volume fraction 71.5%, L/S ratio 12.2 ml/g, microwave power 318 W, and extraction time 143 s. After TFELDC were purified by AB-8 macroporous resin, the total flavonoid contents of PTFELDC increased from 208.18 ± 1.60 to 511.19 ± 3.21 mg RE/g FDS. Compared with TFELDC, the content of total flavonoids in PTFELDC was increased by 2.46 times. The antioxidant activities of PTFELDC were assessed using DPPH radical, superoxide anion radical, reducing power, and ferric reducing antioxidant power assays, and the IC50 values were found to be 37.13, 19.62, 81.22, and 24.72 μg/ml, respectively. The enzyme inhibitory activities of PTFELDC were measured using lipase, α-amylase, α-glucosidase, and acetylcholinesterase assays with the IC50 values 1.38, 2.08, 1.63, and 0.58 mg/ml, respectively. By comparing with their positive controls, it was found that PTFELDC had good antioxidant activities, and lipase, α-amylase, and α-glucosidase inhibitory activities, However, the acetylcholinesterase inhibitory activity was relatively weaker. These results suggested that PTFELDC have a promising potential as natural antioxidant, antilipidemic, and hypoglycemic drugs used in functional foods or pharmaceuticals.

Chemical characterization of Cassia fistula polysaccharide (CFP) and its potential application as a prebiotic in synbiotic preparation

Prebiotics are non-digestible food ingredients that are selectively fermented by probiotics. The aim of this study was to investigate the chemical properties of a polysaccharide extracted from Cassia fistula mature fruit pulp and to evaluate its effects on probiotic strains: L. casei, L. rhamnosus, E. coli Nissle 1917 (EcN), and E. faecalis. These strains were compared for their growth behavior in culture media supplemented with different Cassia fistula polysaccharide (CFP) concentrations. The molecular weight of CFP was approximately 8.707 × 105 Da. The recovered polysaccharide contained a low percentage of crude protein (4.4%). Aspartic acid, glutamic acid, and proline were the most abundant amino acids. Glucose and mannose were the predominant sugars followed by arabinose and rhamnose. L. casei grew faster at high CFP concentrations (2%) compared with the lower concentrations of CFP. The highest values for the prebiotic index and prebiotic activity score were observed for L. casei treated with 2% CFP, and it may be considered a prebiotic due to its high resistance against α-amylase and acidic conditions. CFP provides two ways to adjust nitric oxide (NO) synthesis in macrophages. Finally, the use of 1.5 and 2% CFP for cultured milk production significantly shortened the fermentation period from 210 min to 180 min and 150 min, respectively.

Antioxidative study of polysaccharides extracted from red (Kappaphycus alvarezii), green (Kappaphycus striatus) and brown (Padina gymnospora) marine macroalgae/seaweed

Sterile and fresh tissues of three marine macroalgae red, green and brown (Kappaphycus alvarezii, Kappaphycus striatus and Padina gymnospora) collected from Malaysia east costal seas were compared for the antioxidants and polysaccharide composition of sugars as well as the active components. Results obtained showed that polysaccharides isolated from Kappaphycus alvarezii, Kappaphycus striatus and Padina gymnospora) can be used as a source of natural antioxidant compounds as they possess antioxidant potential in which the Padina gymnospora showed 15.56 ± 0.12 mg/mL to be the best antioxidants among all the polysaccharides studied. The hot water extraction method is effective in isolating polysaccharides from studied seaweeds. The GC–MS analysis revealed that there is presence of chemical compounds such as furfural was 25.53% in Kappaphycus alvarezii and 21.04% in Kappaphycus striatus also Padina gymnospora incorporates n- Hexadecanoic acid about 26.31% in seaweed polysaccharides that contribute to their antioxidant activities. Further studies can be done on determining the seaweed species that are available abundantly with the best source of natural antioxidant compounds.

A water-soluble polysaccharide from Anethum graveolens seeds: Structural characterization, antioxidant activity and potential use as meat preservative

A novel water-soluble polysaccharide named AGP1 was successfully isolated from seeds of Anethum graveolens by hot water extraction and further purified by DEAE-Sepharose chromatography. AGP1 has a relative molecular weight of 2.1 10⁴ Da determined by Ultra-high-performance liquid chromatography (UHPLC). The AGP1 characterization was investigated by chemical and instrumental analysis including gas chromatography mass spectrometry (GC-MS), Fourier transform infrared (FT-IR) spectroscopy and X-ray diffraction. Results showed that AGP1 was mainly composed of glucose, galactose, mannose and arabinose in a molar percent of 54.3, 23.8, 14.7 and 7.2, respectively. The thermogravimetry analysis (TGA) and the differential scanning calorimetry (DSC) were used and showed that AGP1 has good thermal stability until 275 °C. Moreover, the purified polysaccharide demonstrated an appreciable in vitro antioxidant potential. The addition of the AGP1, particularly at 0.3% (w/w), in turkey sausages instead of ascorbic acid, as preservative, reduced the lipid peroxidation, preserved the pH and color and improved the bacterial stability during cold storage at 4 °C for 12 days. Overall, the results showed that the AGP1 deserves to be developed as functional and bioactive components for the food and nutraceutical industries.

Polysaccharides from Hemp Seed Protect against Cyclophosphamide-Induced Intestinal Oxidative Damage via Nrf2-Keap1 Signaling Pathway in Mice

Hemp seed has been used as a traditional oriental medicine and health food in China for centuries. Polysaccharides from hemp seed (HSP) exhibit important properties of intestinal protection, but there are limited data on the specific underlying mechanism. The primary objective of this study was to investigate the protective effect of HSP on intestinal oxidative damage induced by cyclophosphamide (Cy) in mice. The results showed that pretreatment with HSP significantly increased the average daily gain, thymus index, spleen index, superoxide dismutase (SOD), catalase (CAT), and glutathione peroxidase (GSH-Px) activity in serum and ileal homogenate and significantly reduced malondialdehyde (MDA) content in ileal homogenate. In addition, the expression levels of SOD, GSH-Px, Nrf2, heme oxidase-1 (HO-1), and quinoneoxidoreductase-1 (NQO1) mRNA in ileal homogenate were significantly increased. Western blot results showed that HSP significantly upregulated the expression of Nrf2 protein and downregulated the expression of Keap1 protein in the ileum. Collectively, our findings indicated that HSP had protective effects on intestinal oxidative damage induced by Cy in mice, and its mechanism might be related to the activation of Nrf2-Keap1 signaling pathway.

Antibacterial Activity of Sulfated Galactans from Eucheuma serra and Gracilari verrucosa against Diarrheagenic Escherichia coli via the Disruption of the Cell Membrane Structure

Seaweed sulfated polysaccharides have attracted significant attention due to their antibacterial activity. This work investigated the antibacterial activity and mechanism of depolymerized sulfated galactans from Eucheuma serra (E. serra) and Gracilaria verrucosa (G. verrucosa) against enterotoxigenic Escherichia coli (ETEC) K88. The results show that removing the metal ions improves the anti-ETEC K88 activity of the galactans. The fluorescence labeling study confirmed that the sulfated galactans penetrated the cell walls and eventually reached the interior of the ETEC K88. Nucleic acid staining and intracellular protein leakage were also observed, indicating the destruction of permeability and integrity of the cell membrane. Interestingly, the two polysaccharides exhibited no effect on the proliferation of the selected Gram-positive bacteria and yeast. This indicates that the cell wall structure of the microorganisms could influence the bacteriostatic activity of the sulfated polysaccharides, as well. These results suggest that the sulfated seaweed polysaccharides might have potential application value in antibacterial diarrhea.

Mechanisms of Bioactivities of Fucoidan from the Brown Seaweed Fucus vesiculosus L. of the Barents Sea

The aim of this study was to elucidate some mechanisms of radical scavenging and the anti-inflammatory, anti-hyperglycemic, and anti-coagulant bioactivities of high molecular weight fucoidan from Fucus vesiculosus in several in vitro models. Fucoidan has displayed potent 1, 1-diphenyl-2-picryl hydrazil radical scavenging and reduction power activities. It significantly inhibits the cyclooxygenase-2 (COX-2) enzyme (IC50 4.3 μg mL-1) with a greater selectivity index (lg(IC80 COX-2/IC80COX-1), -1.55) than the synthetic non-steroidal anti-inflammatory drug indomethacin (lg(IC80 COX-2/IC80COX-1), -0.09). A concentration-dependent inhibition of hyaluronidase enzyme with an IC50 of 2.9 μg mL-1 was observed. Fucoidan attenuated the lipopolysaccharide-induced expression of mitogen-activated protein kinase p38. Our findings suggest that the inhibition of dipeptidyl peptidase-IV (DPP-IV) (IC50 1.11 μg mL-1) is one of the possible mechanisms involved in the anti-hyperglycemic activity of fucoidan. At a concentration of 3.2 μg mL-1, fucoidan prolongs the activated partial thromboplastin time and thrombin time by 1.5-fold and 2.5-fold compared with a control, respectively. A significant increase of prothrombin time was observed after the concentration of fucoidan was increased above 80 μg mL-1. This evidenced that fucoidan may have an effect on intrinsic/common pathways and little effect on the extrinsic mechanism. This study sheds light on the multiple pathways of the bioactivities of fucoidan. As far as we know, the inhibition of hyaluronidase and DPP-IV by high molecular fucoidan was studied for the first time in this work. Our results and literature data suggest that molecular weight, sulfate content, fucose content, and polyphenols may contribute to these activities. It seems that high molecular weight fucoidan has promising therapeutic applications in different pharmacological settings. Anti-oxidant, anti-inflammatory and anti-coagulant drugs have been used for the management of complications of COVID19. Taken as a whole, fucoidan could be considered as a prospective candidate for the treatment of patients with COVID19; however, additional research in this field is required.

Structural Features and Rheological Properties of a Sulfated Xylogalactan-Rich Fraction Isolated from Tunisian Red Seaweed Jania adhaerens

A novel sulfated xylogalactan-rich fraction (JSP for J. adhaerens Sulfated Polysaccharide) was extracted from the red Tunisian seaweed Jania adhaerens. JSP was purified using an alcoholic precipitation process and characterized by Attenuated Total Reflectance-Fourier-transform infrared spectroscopy (ATR-FTIR), high-pressure size exclusion chromatography (HPSEC) with a multi-angle laser light scattering (MALLS), gas chromatography coupled to mass spectrometry (GC-MS) and nuclear magnetic resonance spectroscopy (NMR, 1D and 2D). JSP was then evaluated regarding its physicochemical and rheological properties. Results showed that JSP was mainly composed of an agar-like xylogalactan sharing the general characteristics of corallinans. The structure of JSP was mainly composed of agaran disaccharidic repeating units (→3)-β-d-Galp-(1,4)-α-l-Galp-(1→)n and (→3)-β-d-Galp-(1,4)-3,6-α-l-AnGalp-(1→)n, mainly substituted on O-6 of (1,3)-β-d-Galp residues by β-xylosyl side chains, and less with sulfate or methoxy groups. (1,4)-α-l-Galp residues were also substituted by methoxy and/or sulfate groups in the O-2 and O-3 positions. Mass-average and number-average molecular masses (Mw) and (Mn), intrinsic viscosity ([η]) and hydrodynamic radius (Rh) for JSP were, respectively, 8.0 × 105 g/mol, 1.0 × 105 g/mol, 76 mL/g and 16.8 nm, showing a flexible random coil conformation in solution. The critical overlap concentration C* of JSP was evaluated at 7.5 g/L using the Williamson model. In the semi-diluted regime, JSP solutions displayed a shear-thinning behavior with a great viscoelasticity character influenced by temperature and monovalent salts. The flow characteristics of JSP were described by the Ostwald model.

Sulphated polysaccharide from Sargassum myriocystum confers protection against gentamicin-induced nephrotoxicity in adult zebrafish

The beneficial effect of purified fraction of sulphated polysaccharide extracted from Sargassum myriocystum (SMP) was examined on the gentamicin-induced nephrotoxicity in adult zebrafish. The major purified fractions (SMP1, SMP2 and SMP3) were obtained by anion-exchange and size-exclusion chromatography and characterized by FTIR, GCMS and NMR. The in vitro antioxidant activities of all purified SMP fractions were analysed. The SMP2 showed maximum carbohydrate, sulphate and fucose content with strong antioxidant activity than other fractions. Further, we evaluated the efficacy of SMP2 against gentamicin-induced nephrotoxicity in zebrafish model. The SMP2 administered group showed a significant attenuation in oxidative stress and histopathological alterations observed in renal tissues of gentamicin treated group. Moreover, the SMP2 supressed renal mRNA expression levels of KIM-1, NF-κB, TNF-α and IL-6 in dose-dependent manner. Thus, the present study suggests that the SMP2 is a potent antioxidant with anti-inflammatory and renoprotective properties that ameliorated the GEN induced nephrotoxicity in adult zebrafish.

Isolation and structural characterization of sulfated polysaccharide from Spirulina platensis and its bioactive potential: In vitro antioxidant, antibacterial activity and Zebrafish growth and reproductive performance

In this study, the sulfated polysaccharide (SPs) was isolated from Spirulina platensis. The isolated SPs contains carbohydrate, sulfate, protein and uronic acid at 38.7 ± 0.30%, 21.3 ± 0.87%, 7.1 ± 0.15% and 7.9 ± 0.4% respectively. The elemental analysis confirmed the presence of carbon (18.01 ± 0.10%), hydrogen (1.83 ± 0.02%) and nitrogen (3.43 ± 0.01%). The monosaccharide composition and molecular weight of SPs were analyzed by high-performance liquid chromatography and size exclusion chromatography respectively. The monosaccharide composition analysis showed the existence of glucose, rhamnose, xylose, fucose, mannose, galactose and the molecular weight of SPs was 1016 kDa. Further, the characterization of SPs was done by UV-visible spectroscopy, X-ray diffraction, FT-IR, ¹H NMR and ¹³C NMR analysis. The obtained SPs exhibited potent antioxidant activity in DPPH (76.45 ± 0.49%), reducing power (absorbance: 1.3 ± 0.02), hydrogen peroxide scavenging (66.3 ± 1.16%), hydroxyl scavenging (68.6 ± 3.2%), nitric oxide (81.36 ± 1.85%) and total antioxidant (absorbance:1.66 ± 0.02) activities at 5 mg/ml. In addition, SPs revealed the highest antibacterial efficacy against the pathogenic bacteria Vibrio vulnificus in disc diffusion, agar bioassay and protein leakage assays at 100 μg/ml. Furthermore, the supplementation of 2% SPs through a feed to the Danio rerio fish enhances the growth and reproductive performances. This finding confirmed that the isolated SPs from S. platensis possess pharmaceutical as well as nutritional properties.

Seaweeds as Source of Bioactive Substances and Skin Care Therapy—Cosmeceuticals, Algotheraphy, and Thalassotherapy

Riverine, estuarine, and coastal populations have always used algae in the development of home remedies that were then used to treat diverse health problems. The empirical knowledge of various generations originated these applications, and their mechanism of action is, in most cases, unknown, that is, few more scientific studies would have been described beyond simple collection and ethnographic recording. Nevertheless, recent investigations, carried out with the purpose of analyzing the components and causes that alter the functioning and the balance of our organism, are already giving their first results. Water, and especially sea water is considered as essential to life on our planet. It sings all the substances necessary and conducive to the development of the living being (minerals, catalysts, vitamins, amino acids, etc.). Oceans cover over 70% of Earth, being home to up to 90% of the organisms in the planet. Many rich resources and unique environments are provided by the ocean. Additionally, bioactive compounds that multiple marine organisms have a great potential to produce can be used as nutraceuticals, pharmaceuticals, and cosmeceuticals. Both primary and secondary metabolites are produced by algae. The first ones are directly implicated in development, normal growth, or reproduction conditions to perform physiological functions. Stress conditions, like temperature changes, salinity, environmental pollutants, or UV radiation exposure cause the performance of secondary metabolites. In algae, proteins, polysaccharides, fatty acids, and amino acids are primary metabolites and phenolic compounds, pigments, vitamins, sterols, and other bioactive agents, all produced in algae tissues, are secondary metabolites. These algal active constituents have direct relevance in cosmetics.

Extraction, characterization and biological activity of sulfated polysaccharides from seaweed Dictyopteris divaricata

Dictyopteris divaricata is a kind of important brown algae with many biological activities. It has been receiving more and more attention, yet there are rarely studies done on its polysaccharides. In this study, the optimum extraction and biological activity of seaweed polysaccharides from Dictyopteris divaricata (DDSP) were investigated. Response surface methodology (RSM), based on a three-level, three-variable Box-Behnken design (BBD), was employed to obtain the best possible combinations for maximum polysaccharides yield. The optimum extraction conditions were as follows: liquid-solid ratio of 110 mL/g, extraction time of 6 h and extraction temperature of 100 °C. Under these conditions, the experimental yield was 3.05%, which was in close agreement with the predicted value of 3.15%. The average molecular weight of DDSP was 58.05 kDa. Gas chromatograph (GC) results showed that DDSP was composed of fucose, xylose, mannose, glucose and galactose with the corresponding molar ratio of 4.45:2.74:1.00:2.94:1.35. Biological activity showed that DDSP exhibited strong antioxidant activity in vitro and possessed the potential on stimulating immune response of RAW264.7 cells. So DDSP can be used as a natural ingredient in functional foods.

Pigment patterns and photoprotection of anthocyanins in the young leaves of four dominant subtropical forest tree species in two successional stages under contrasting light conditions

Light-driven subtropical forest succession is a dynamic process in which mesophytic climax communities replace heliophytic ones. Juvenile leaves (particularly mesophytic ones) are sensitive to high irradiances. To determine the photoprotection strategy that juvenile leaves use during subtropical forest succession, anthocyanin accumulation patterns were investigated in the young leaves of two mid-successional dominant trees (i.e., Schima superba and Castanopsis fissa) and two late-successional dominant trees (i.e., Cryptocarya concinna and Acmena acuminatissima) grown in 100% (FL) and 25% (LL) of full sunlight. All four tree species produced anthocyanins in their juvenile leaves when <50% of chlorophylls and carotenoids had developed. Higher anthocyanin concentrations accumulated in the young leaves grown in FL than in those grown in LL and in late-successional than in mid-successional trees. The juvenile leaves of late-successional trees were subjected to higher light-induced photoinhibition than those of mid-successional trees, despite of the fact that the leaves of late-successional trees showed greater non-photochemical quenching than those of mid-successional trees. Under LL conditions, photosystem II excitation pressure (1 - qP) was significantly higher in the juvenile leaves of late-successional trees than those of mid-successional trees. Under either FL or LL conditions, anthocyanin concentrations in juvenile leaves were negatively related to the light compensation point in mature leaves across species. However, anthocyanin concentrations were positively related to the antioxidant capacity of juvenile leaves. These results indicate that anthocyanin accumulation in the juvenile leaves of subtropical dominant trees during forest community succession is a flexible photoprotective response to ambient irradiances according to leaf sensitivity to light.

Preparation and in vitro antioxidant activities of 6-amino-6-deoxychitosan and its sulfonated derivatives

The 6-amino-6-deoxychitosan (NC) and their 2, 6-di-N-sulfonated derivatives were prepared via N-phthaloylation, tosylation, azidation, hydrazinolysis, reduction of azide groups and N-sulfonation, and their structures were systematically characterized by FT-IR, 2D HSQC NMR, XRD, gel permeation chromatography (GPC), and elemental analysis. The 6-amino-6-deoxychitosan showed effect in three selected antioxidant essays, including reducing power, superoxide anion radical scavenging ability, and hydroxyl radical scavenging effect. But the factors affecting each activity were different. The reducing power and the superoxide anion radical scavenging ability of NC were strong and closely related to the amino groups in the molecular chains. Both introducing N-sulfonated groups into NC and the concentration reduction of NC and its sulfonated derivatives decreased these activities. For the superoxide anion radical, the molecular charge property was also a significant influence factor. For the hydroxyl radical, NC only showed weak scavenging activity in a special inverse concentration-dependent manner. However, the incorporation of N-sulfonated groups significantly improved the scavenging activity, and the more N-sulfonated groups, the higher the concentrations, the stronger the activity was. The results could be due to the different conformations of NC and its sulfonated derivatives in aqueous solution.

Reviews on Mechanisms of In Vitro Antioxidant Activity of Polysaccharides

It is widely acknowledged that the excessive reactive oxygen species (ROS) or reactive nitrogen species (RNS) induced oxidative stress will cause significant damage to cell structure and biomolecular function, directly or indirectly leading to a number of diseases. The overproduction of ROS/RNS will be balanced by nonenzymatic antioxidants and antioxidant enzymes. Polysaccharide or glycoconjugates derived from natural products are of considerable interest from the viewpoint of potent in vivo and in vitro antioxidant activities recently. Particularly, with regard to the in vitro antioxidant systems, polysaccharides are considered as effective free radical scavenger, reducing agent, and ferrous chelator in most of the reports. However, the underlying mechanisms of these antioxidant actions have not been illustrated systematically and sometimes controversial results appeared among various literatures. To address this issue, we summarized the latest discoveries and advancements in the study of antioxidative polysaccharides and gave a detailed description of the possible mechanisms.

Characteristics and antioxidant of Ulva intestinalis sulphated polysaccharides extracted with different solvents

Ulva intestinalis, a tubular green seaweed, is a rich source of nutrient, especially sulphated polysaccharides. Sulphated polysaccharides from U. intestinalis were extracted with distilled water, 0.1N HCl, and 0.1N NaOH at 80°C for 1, 3, 6, 12, and 24h to study the effect of the extraction solvent and time on their chemical composition and antioxidant activity. Different types of solvents and extraction time had a significant influence on the chemical characteristics and antioxidant activity (p<0.05). Monosaccharide composition and FT-IR spectra analyses revealed that sulphated polysaccharides from all solvent extractions have a typical sugar backbone (glucose, rhamnose, and sulphate attached at C-2 or C-3 of rhamnose). Sulphated polysaccharides extracted with acid exhibited greater antioxidant activity than did those extracted with distilled water and alkali. The results indicated that solvent extraction could be an efficacious method for enhancing antioxidant activity by distinct molecular weight and chemical characteristic of sulphated polysaccharides.