Antiviral polysaccharides isolated from Hong Kong brown seaweed Hydroclathrus clathratus

Seaweeds in the Oncology Arena: Anti-Cancer Potential of Fucoidan as a Drug—A Review

Marine natural products are a discerning arena to search for the future generation of medications to treat a spectrum of ailments. Meanwhile, cancer is becoming more ubiquitous over the world, and the likelihood of dying from it is rising. Surgery, radiation, and chemotherapy are the mainstays of cancer treatment worldwide, but their extensive side effects limit their curative effect. The quest for low-toxicity marine drugs to prevent and treat cancer is one of the current research priorities of researchers. Fucoidan, an algal sulfated polysaccharide, is a potent therapeutic lead candidate against cancer, signifying that far more research is needed. Fucoidan is a versatile, nontoxic marine-origin heteropolysaccharide that has received much attention due to its beneficial biological properties and safety. Fucoidan has been demonstrated to exhibit a variety of conventional bioactivities, such as antiviral, antioxidant, and immune-modulatory characteristics, and anticancer activity against a wide range of malignancies has also recently been discovered. Fucoidan inhibits tumorigenesis by prompting cell cycle arrest and apoptosis, blocking metastasis and angiogenesis, and modulating physiological signaling molecules. This review compiles the molecular and cellular aspects, immunomodulatory and anticancer actions of fucoidan as a natural marine anticancer agent. Specific fucoidan and membranaceous polysaccharides from Ecklonia cava, Laminaria japonica, Fucus vesiculosus, Astragalus, Ascophyllum nodosum, Codium fragile serving as potential anticancer marine drugs are discussed in this review.

The Antiviral Activity of Bacterial, Fungal, and Algal Polysaccharides as Bioactive Ingredients: Potential Uses for Enhancing Immune Systems and Preventing Viruses

Viral infections may cause serious human diseases. For instance, the recent appearance of the novel virus, SARS-CoV-2, causing COVID-19, has spread globally and is a serious public health concern. The consumption of healthy, proper, functional, and nutrient-rich foods has an important role in enhancing an individual's immune system and preventing viral infections. Several polysaccharides from natural sources such as algae, bacteria, and fungi have been considered as generally recognized as safe (GRAS) by the US Food and Drug Administration. They are safe, low-toxicity, biodegradable, and have biological activities. In this review, the bioactive polysaccharides derived from various microorganisms, including bacteria, fungi, and algae were evaluated. Antiviral mechanisms of these polysaccharides were discussed. Finally, the potential use of microbial and algal polysaccharides as an antiviral and immune boosting strategy was addressed. The microbial polysaccharides exhibited several bioactivities, including antioxidant, anti-inflammatory, antimicrobial, antitumor, and immunomodulatory activities. Some microbes are able to produce sulfated polysaccharides, which are well-known to exert a board spectrum of biological activities, especially antiviral properties. Microbial polysaccharide can inhibit various viruses using different mechanisms. Furthermore, these microbial polysaccharides are also able to modulate immune responses to prevent and/or inhibit virus infections. There are many molecular factors influencing their bioactivities, e.g., functional groups, conformations, compositions, and molecular weight. At this stage of development, microbial polysaccharides will be used as adjuvants, nutrient supplements, and for drug delivery to prevent several virus infections, especially SARS-CoV-2 infection.

Production, structural and biochemical characterization relevant to antitumor property of acidic exopolysaccharide produced from Bacillus sp. NRC5

This study targeted the production of exopolysaccharide from Bacillus sp. NRC5 grown in Egyptian seawater to use it as natural antitumor therapy. The biological activities of selected exopolysaccharide (BEPS) as an antioxidant, anti-inflammatory and anticancer have been studied. BEPS was evaluated as an anti-inflammatory in vitro against cyclooxygenase (COX-1 and COX-2) and evaluated as an anticancer on human breast and prostate cancer cell lines (MCF-7 and PC3). In addition, BEPS antitumor activity was tested against the Ehrlich Ascites Carcinoma (EAC) model. The BEPS presented potent antioxidant activities, consisted of glucose, mannose, and mannuronic acid in a molar ratio of 1.0:1.7:0.8 with a molecular weight of 3.59 × 10⁵ g/mol. BEPS showed a promising COX-2 inhibitory effect in comparison with the reference drug celecoxib. BEPS appeared efficient anticancer property, where it killed 64.20 and 70.20% of MCF-7 and PC3 cells at 100 µg/ml, respectively (IC₅₀, 76.70, and 70.40 µg/ml, respectively). BEPS exhibited antitumor ability as it prolonged the lifespan of mice to reach 75 days instead of 20 days in the tumor control, reduced viable cancer cells count, tumor volume and weight, modulated blood components, and white blood cells differentiation. BEPS produced from Bacillus sp. NRC5 showed its antioxidant and anti-inflammatory abilities and antitumor abilities, which may all be attributed to its unique composition containing sulfated moieties and uronic acids.

Biomedical and therapeutic potential of exopolysaccharides by Lactobacillus paracasei isolated from sauerkraut: Screening and characterization

The intention of the study was evaluated for purification and characterization of exopolysaccharides from Lactobacillus paracasei; was isolated from homemade Sauerkraut sample collected from Sivakasi, Tamil Nadu, India, confirmed by biochemical and gene sequencing (16S rRNA). The purification and characterization of exopolysaccharides from candidate bacterium were studied on appearance, solubility of the EPS, carbohydrate estimation, emulsifying activity, sulphate, protein, uronic acid content, FTIR, HPLC and GC-MS analysis. The percentage of elemental carbon, (54.36%) hydrogen (21.74%), nitrogen (9.63%) and sulphur content (18.03%) were recorded in exopolysaccharides. The emulsification index (E24) of EPS was higher in toluene (79.20) and benzene (78.867) supplemented medium. FTIR spectrum of the candidate bacterial EPS confirmed presence of sulphate compounds, carboxyl group, and hydrogen bonded compounds etc. EPS exhibited 76.34% of Total Antioxidant Capacity (TAC), 71.15% of reducing power, 68.65% of Hydrogen Peroxide scavenging activity and also 60.31% DPPH radical scavenging activity. The potential antioxidant properties observed in exopolysaccharides from Lactobacillus paracasei is considered as valuable drugs.

Hydroclathrus clathratus as anti-damaging agent against lung injury in male albino rats

Background

The present investigation is designed to evaluate the antioxidant and protective efficacy of the brown alga, Hydroclathrus clathratus (C.Agardh) M. Howe, against copper-induced lung injury in male albino rats. The present study was carried out on 24 adult male albino rats, they were randomly divided into four groups (n = 6) (A group, control rats; B group, rats received 100 mg/kg body weight of H. clathratus ethanolic extract; C group, rats augmented with 100 mg/kg body weight of CuSO4; and D group, rats were supplemented with 100 mg/kg of CuSO4 and 100 mg/kg of H. clathratus ethanolic extract). All the experimental treatments were given orally and daily for 28 days.

Results

It was showing that Cu treatment was found to induce lung toxicity, histopathologically, Cu revealed severe degenerative and necrotic lesions in the lung. Also, Cu caused a significant decrease in glutathione-S-transferase (GST) count and glutathione (GSH); meanwhile, malondialdehyde (MDA) content was increased. Consistently, mRNA and protein expression levels of proapoptotic (caspase-3 and Bax) marker showed a significant upregulation, whereas the anti-apoptotic (Bcl-2) level was significantly downregulated in lung tissues of CuSO4-intubated groups. Moreover, H. clathratus plus CuSO4-treated group showed improvement in the histopathological changes of lung injury. The bronchi and bronchioles appeared like those of the control, where the alveoli showed thin septa in some parts and thickened septa in other parts.

Conclusion

Findings revealed that the natural antioxidant activity of H. clathratus could protect the lung tissue from the damage produced by CuSO4.

Production, characterization and biological activities of acidic exopolysaccharide from marine Bacillus amyloliquefaciens 3MS 2017

OBJECTIVE

To evaluate in-vitro antioxidant, anti-inflammatory and antitumor abilities against human breast adenocarcinoma (MCF7) and human prostate cancer (PC3) as well as the suppressor effect of bacterial exopolysaccharide (BAEPS) on Ehrlich ascites carcinoma (EAC).

METHODS

In-vitro antioxidants characters of BAEPS were determined using various methods, while anti-inflammatory activity was estimated against cyclooxygenase (COX-1 and COX-2). In-vitro study, anticancer against MCF7 and PC3 were assessed by the mitochondrial dependent reduction of yellow MTT. In in-vivo study against EAC progression, mice were inoculated with EAC cells and then were orally administered BAEPS at 200 mg/kg after 24 h (equals to 0.10 of determined LD₅₀)/10 d.

RESULTS

BAEPS was acidic exopolysaccharide contained uronic acid (12.3%) and sulfate (22.8%) with constitution of glucose, galactose and glucuronic acid in a molar ratio 1.6:1.0:0.9, respectively, with a molecular mass of 3.76 × 10⁴ g/mol. BAEPS appeared potent antioxidant characters as free radical scavenging, oxygen reactive species scavenging and metal chelation, while its reducing power was low. BAEPS showed selective anti-inflammatory activity against COX-2 than COX-1, COX-2 selective. BAEPS exhibited potent and selective effect to breast cell cancer MCF7, the death percentage was 65.20% with IC₅₀ = 70 μg/mL and IC₉₀ = 127.40 μg/mL. BAEPS decreased counted viable EAC cells and induced non-viable cells. BAEPS improved all assessed hematological parameters. These improvements were reflected in the increasing median survival time and significant increment (P < 0.05) in life span.

CONCLUSIONS

BAEPS has anti-tumor activity with a good margin of safety. The anti-tumor activity of BAEPS may be due to its content from sulfated groups and uronic acids and they have antioxidant and anti-inflammatory properties.

Chemoprevention of Diethylnitrosamine-Initiated and Phenobarbital-Promoted Hepatocarcinogenesis in Rats by Sulfated Polysaccharides and Aqueous Extract of Ulva lactuca

Hepatocellular carcinoma (HCC) is one of the common cancers and lethal diseases worldwide. Both oxidative stress and chronic inflammation contribute to the pathogenesis of HCC. Because of limited treatment options and a grave prognosis of HCC, preventive management has been emphasized. The marine macroalgae Ulva lactuca (Ulvaceae) is consumed by humans and livestock because of its nutritional value. Recent studies showed that various extracts of U. lactuca possess antiviral, antiplasmodial, antinephrotoxic, antioxidant, and anti-inflammatory properties. However, very limited information is available on anticancer potential of U. lactuca with no reports on liver cancer chemopreventive efficacy of this marine algae. Accordingly, the present study was initiated to evaluate the possible antihepatocarcinogenic effects and antioxidant mechanisms of action of various U. lactuca extracts against a clinically relevant rodent model of HCC. Initiation of hepatocarcinogenesis was performed in Sprague-Dawley rats by a single injection of dietary carcinogen diethylnitrosamine (DENA, 200 mg/kg, intraperitoneally), followed by promotion with phenobarbital (0.05%) in drinking water. The rats were fed with daily oral dose (50 mg/kg) of polysaccharide sulfate or aqueous extract of U. lactuca for 2, 12, and 24 weeks. At these timepoints, blood samples were taken to measure hepatic injury markers, including alanine aminotransferase, aspartate aminotransferase, alkaline phosphatase, γ-glutamyl transferase, and bilirubin. The liver tissue was harvested for measurement of hepatic oxidative indices, including lipid peroxidation, reduced glutathione, nitric oxide, catalase, superoxide dismutase, glutathione reductase, and glutathione S-transferase. Hepatic histopathology, immunohistochemical analysis of cell proliferation and apoptosis by DNA fragmentation assay were performed. Our results clearly indicate that sulfated polysaccharides of U. lactuca exert a marked chemoprevention of DENA-initiated hepatocarcinogenesis through inhibition of abnormal cell proliferation and induction of apoptosis. A modest inhibition rat liver carcinogenesis was observed with the aqueous extract. The sulfated polysaccharides altered serum parameters of hepatic damage and modulated various components of the hepatic enzymatic and nonenzymatic antioxidant defense systems. The sulfated polysaccharides from U. lactuca may have unique properties of providing protection against DENA-induced oxidative stress which could contribute to chemoprevention of experimental hepatocarcinogenesis. U. lactuca sulfated polysaccharides could be developed as chemopreventive and therapeutic drug against human HCC.

Antiviral activities of extracts from Hong Kong seaweeds

We extracted six Hong Kong brown seaweed species with hot water for their antiviral properties. The cytotoxicity and antiviral activity of these extracts were tested by MTT [3-(4,5-dimethylthiazol-2-yl)-2,5-diphenlytetrezolium bromide] method, cytopathic effect reduction assay, and plaque reduction assay. The antiviral effect was further determined by flow cytometric analysis. The results showed that most of these extracts inhibited the propagation of herpes simplex virus types 1 and 2 (HSV-1 and HSV-2) standard strains with very low cytotoxicity to the host cells. The extracts of Hydroclathrus clathratus and Lobophora variegata showed more potential anti-HSV activities than the extracts of the other four seaweeds. They also had moderate anti- respiratory syncytial virus (RSV) activities but could not inhibit influenza A virus. Hydroclathrus clathratus was further extracted by diluted acid and alkali and the antiviral effects of the extracts were also detected. The result showed that the hot water extract contained the main carbohydrate components that exhibited the antiviral activities against various strains of HSV, including the acyclovir-resistant strain. HI-3, a compound fractionated from this hot water extract, showed a dose-dependent anti-HSV activity in flow cytometric analysis and plaque reduction assay.

Fucoidan: structure and bioactivity

Fucoidan refers to a type of polysaccharide which contains substantial percentages of L-fucose and sulfate ester groups, mainly derived from brown seaweed. For the past decade fucoidan has been extensively studied due to its numerous interesting biological activities. Recently the search for new drugs has raised interest in fucoidans. In the past few years, several fucoidans' structures have been solved, and many aspects of their biological activity have been elucidated. This review summarizes the research progress on the structure and bioactivity of fucoidan and the relationships between structure and bioactivity.