Cyanometabolites: molecules with immense antiviral potential

Cyanometabolites are active compounds derived from cyanobacteria that include small low molecular weight peptides, oligosaccharides, lectins, phenols, fatty acids, and alkaloids. Some of these compounds may pose a threat to human and environment. However, majority of them are known to have various health benefits with antiviral properties against pathogenic viruses including Human immunodeficiency virus (HIV), Ebola virus (EBOV), Herpes simplex virus (HSV), Influenza A virus (IAV) etc. Cyanometabolites classified as lectins include scytovirin (SVN), Oscillatoria agardhii agglutinin (OAAH), cyanovirin-N (CV-N), Microcystis viridis lectin (MVL), and microvirin (MVN) also possess a potent antiviral activity against viral diseases with unique properties to recognize different viral epitopes. Studies showed that a small linear peptide, microginin FR1, isolated from a water bloom of Microcystis species, inhibits angiotensin-converting enzyme (ACE), making it useful for the treatment of coronavirus disease 2019 (COVID-19). Our review provides an overview of the antiviral properties of cyanobacteria from the late 90s till now and emphasizes the significance of their metabolites in combating viral diseases, particularly severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), which has received limited attention in previous publications. The enormous medicinal potential of cyanobacteria is also emphasized in this review, which justifies their use as a dietary supplement to fend off pandemics in future.

Physicochemical characteristics and biological activities of grape polysaccharides collected from different cultivars

In this study, four wine grape polysaccharides were extracted and optimized by using an efficient ultrasound-assisted extraction. A three-level, three-factor Box Behnken Design (BBD) combining with response surface methodology (RSM) was employed to optimize the extraction conditions including ultrasonic power, ultrasonic time and liquid-to-solid ratio. Furthermore, their physicochemical structures, antioxidant and liver protective activity were investigated and compared. Results revealed that the functional groups and monosaccharide compositions of these grape polysaccharides collected from different varieties were similar. Nevertheless, their molecular weights, molar ratios of monosaccharide compositions and surface morphological features were different. And the antioxidant activities of these polysaccharides were screened by free radical scavenging test. 'Beichun' (BC) and 'Benni fuji' (BF) polysaccharides possessed better antioxidant function. Further, the in vivo evaluation indicated that the polysaccharides of BC and BF have a protective effect against myocardial I/R injury in mice by inhibiting myocardial necroptosis mediated by mitochondrial ROS generation. Therefore, BC and BF grapes have potential applications in the medical and food industries.

Beneficial Effects of Holothuria leucospilota Polysaccharides on Fermentability In Vivo and In Vitro

This work aimed to investigate the in-vitro and in-vivo fermentation behaviors of Holothuria leucospilota Polysaccharides (HLP) and the impact on mouse liver antioxidant activity. HLP showed excellent fermentability during in vitro experiments, which was characterized by increased levels of total sugar consumption and short-chain fatty acids (SCFAs). During in vitro fecal fermentation, the fucose contents in the HLP fermentation products (0.174 mg/mL) were higher than those of xylose and galactosamine during the first three hours, and fucose disappeared after 24 h. The concentrations of the generated SCFAs increased to 111.13 mmol/mL after in-vitro fermentation at 48 h. After 28 days of oral administration, the SCFA contents that were detected in the feces of mice treated with high HLP doses were significantly higher than those in the feces of mice treated with lower doses and the normal group. In addition, histological observations demonstrated that HLP increased the number of goblet cells without causing hepatocellular injury. Moreover, the increased glutathione peroxidase (GSH-Px) and superoxidase dismutase (SOD) activities and decreased malondialdehyde (MDA) contents in the mouse livers treated with HLP suggested the good performance of HLP with respect to liver antioxidants.

Potentials of Antitussive Traditional Persian Functional Foods for COVID-19 Therapy†

Coronavirus disease 2019 is a worldwide pandemic resulting in a severe acute respiratory syndrome. Remdesivir is the only FDA-approved drug for hospitalized patients older than age 12. It shows the necessity of finding new therapeutic strategies. Functional foods (FFs) could have co-therapeutic and protective effects against COVID-19 infection. Traditional Persian medicine (TPM), one of the safest and most popular schools of medicine for hundreds of years, has recommended potential FF candidates to manage such a global pandemic. To reveal the potential of TPM in terms of antitussive FFs, traditional Persian pharmacopoeia "Qarabadin-e-Salehi" was searched using the keywords "Soaal" and "Sorfeh." Also, a search of MEDLINE, PubMed Central, Google Scholar, and Science Direct was performed for the relevant literature published from the inception up to March 2021. A combination of search terms including "cough, antitussive, antioxidant, anti-inflammation, antiviral, COVID-19, mucoactive, mucolytic, expectorant, and mucoregulatory" was also applied. The potential mechanism of action in SARS-CoV-2 infection was discussed. Twelve TPM FFs were found including Laooqs, Morabbas, a Saviq, a soup, and a syrup. They are combinations of two to seven ingredients. Natural compounds of mentioned formulations have the main pharmacological mechanisms including antiviral, anti-inflammatory, antioxidant, antihistamine, bronchodilator, immunomodulatory, and mucoactive effects as well as central or peripheral antitussive activities. FFs are cost-effective, easily accessible, and safe options for both treatment and prevention of COVID-19. They might have positive psychological effects along with their pharmacological effects and nutritional virtues. They could also manage persistent respiratory discomforts after recovery from COVID-19.

Antiviral Cyanometabolites-A Review

Global processes, such as climate change, frequent and distant travelling and population growth, increase the risk of viral infection spread. Unfortunately, the number of effective and accessible medicines for the prevention and treatment of these infections is limited. Therefore, in recent years, efforts have been intensified to develop new antiviral medicines or vaccines. In this review article, the structure and activity of the most promising antiviral cyanobacterial products are presented. The antiviral cyanometabolites are mainly active against the human immunodeficiency virus (HIV) and other enveloped viruses such as herpes simplex virus (HSV), Ebola or the influenza viruses. The majority of the metabolites are classified as lectins, monomeric or dimeric proteins with unique amino acid sequences. They all show activity at the nanomolar range but differ in carbohydrate specificity and recognize a different epitope on high mannose oligosaccharides. The cyanobacterial lectins include cyanovirin-N (CV-N), scytovirin (SVN), microvirin (MVN), Microcystisviridis lectin (MVL), and Oscillatoria agardhii agglutinin (OAA). Cyanobacterial polysaccharides, peptides, and other metabolites also have potential to be used as antiviral drugs. The sulfated polysaccharide, calcium spirulan (CA-SP), inhibited infection by enveloped viruses, stimulated the immune system’s response, and showed antitumor activity. Microginins, the linear peptides, inhibit angiotensin-converting enzyme (ACE), therefore, their use in the treatment of COVID-19 patients with injury of the ACE2 expressing organs is considered. In addition, many cyanobacterial extracts were revealed to have antiviral activities, but the active agents have not been identified. This fact provides a good basis for further studies on the therapeutic potential of these microorganisms.

Polysaccharides; Classification, Chemical Properties, and Future Perspective Applications in Fields of Pharmacology and Biological Medicine (A Review of Current Applications and Upcoming Potentialities)

Polysaccharides are essential macromolecules which almost exist in all living forms, and have important biological functions, they are getting more attention because they exhibit a wide range of biological and pharmacological activities, such as anti-tumour, immunomodulatory, antimicrobial, antioxidant, anticoagulant, antidiabetic, antiviral, and hypoglycemia activities, making them one of the most promising candidates in biomedical and pharmaceutical fields. Polysaccharides can be obtained from many different sources, such as plants, microorganisms, algae, and animals. Due to their physicochemical properties, they are susceptible to physical and chemical modifications leading to enhanced properties, which is the basic concept for their diverse applications in biomedical and pharmaceutical fields. In this review, we will give insight into the most recent updated applications of polysaccharides and their potentialities as alternatives for traditional and conventional therapies. Challenges and limitations for polysaccharides in pharmaceutical utilities are discussed as well.

Targeting the tumor immune microenvironment with "nutraceuticals": From bench to clinical trials

The occurrence of immune effector cells in the tissue microenvironment during neoplastic progression is critical in determining tumor growth outcomes. On the other hand, tumors may also avoid immune system-mediated elimination by recruiting immunosuppressive leukocytes and soluble factors, which coordinate a tumor microenvironment that counteracts the efficiency of the antitumor immune response. Checkpoint inhibitor therapy results have indicated a way forward via activation of the immune system against cancer. Widespread evidence has shown that different compounds in foods, when administered as purified substances, can act as immunomodulators in humans and animals. Although there is no universally accepted definition of nutraceuticals, the term identifies a wide category of natural compounds that may impact health and disease statuses and includes purified substances from natural sources, plant extracts, dietary supplements, vitamins, phytonutrients, and various products with combinations of functional ingredients. In this review, we summarize the current knowledge on the immunomodulatory effects of nutraceuticals with a special focus on the cancer microenvironment, highlighting the conceptual benefits or drawbacks and subtle cell-specific effects of nutraceuticals for envisioning future therapies employing nutraceuticals as chemoadjuvants.

Nanocomposite Cryogel Carriers from 2-Hydroxyethyl Cellulose Network and Cannabidiol-Loaded Polymeric Micelles for Sustained Topical Delivery

In this contribution, we report the development of original nanocomposite cryogels for sustained topical delivery of hydrophobic natural active substances such as cannabidiol (CBD). The cryogels were fabricated by a method involving cryogenic treatment and photo-crosslinking of aqueous systems containing biodegradable 2-hydroxyethyl cellulose (HEC) and CBD-loaded polymeric micelles. The preparation of the water-soluble form of CBD was a key element for the successful drug loading in the one-pot reaction. The main physical, mechanical and biological characteristics of CBD-loaded and blank cryogels such as gel fraction yield, swelling degree, morphology, storage and loss moduli, and cytotoxicity were studied in detail. The advantage of nanocomposite over pure HEC cryogel carriers in terms of achieving a sustained release profile was also demonstrated.