ABSTRACT
Infectious diseases of viral origin have never received so much interest globally since the emergence of the COVID-19 pandemic disease. In contrast to bacterial infections, antibiotic treatments do not have any effect on viral infections, requiring alternative solutions to reduce the impact of viral spread on animal populations. More important than curing, preventing viral replication before disease development is probably the best strategy to minimalize the negative effects of viruses on a global scale. Fructans, known to stimulate the immune system (by either interacting directly or indirectly with the immune system), may be interesting candidates as part of this broader prevention strategy. This chapter discusses the potential antiviral properties of fructans in relation to their well-described immunomodulating, antioxidant and prebiotic attributes, as well as a possible role as protein binders which may disturb the proper function of viral proteins, and thus reduce the infection ability of certain viral strains. © 2023 Elsevier Inc. All rights reserved.
ABSTRACT
Various strategies, like those using vaccines and antibiotics, have been examined for the prevention and treatment of virus's diseases, but until this moment infection control is not at sufficient level. Exopolysaccharides, especially from probiotics, became one of the most innovative approaches for antiviral agents. This research tried to highlight the effect of a probiotic polysaccharide, such as levan, in COVID-19 prevention. Accordingly, 5 levans types previously obtained from bacterial honey isolates were tested against COVID-19. The most promising result was recorded with levans from Pseudomonas aeruginosa HI1 (levAE) and Bacillus subtilis 9A (lev9A). The lowest cytotoxicity was obtained from lev9A (CC50=5.567e+006 mg/ml) and the most promising IC50 was obtained by levAE (10.75 mg/ml) followed by lev13M (142.5 mg/ml) then lev9A (1299 mg/ml). The dialysis process of levAE greatly affected the virus inhibition activity (IC50 of levAE/D =7.773e+006 mg/ml). Pseudomonas aeruginosa HI1 and Bacillus subtilis 9A were highly tolerant to the acidic (pHs 2, 3) and alkaline conditions (pHs 9, 11). Moreover, when incubated with 0.3 bile salt for 24h, their surviving rates recorded 94% and 100% respectively. H2O2 tolerance showed 77% surviving of Pseudomonas aeruginosa HI1 and 100% surviving of Bacillus subtilis 9A. The blood hemolysis and the antibiotics sensitivity tests confirmed the isolate's safety. The hypothesis that the isolates adhere to the lung cells, could explain the ability of the isolates and their levans to inhibit covid-19 replication. © 2022 National Information and Documentation Center.
ABSTRACT
Phototherapies, including photodynamic therapy (PDT), have been widely used in the treatment of various diseases, especially for cancer. However, there is still a lack of effective, safe photosensitizers that would be well tolerated by patients. The combination of several methods (like phototherapy and hyperthermia) constitutes a modern therapeutic approach, which demands new materials based on components that are non-toxic without irradiation. Therefore, this study presents the synthesis and properties of novel, advanced nanomaterials in which the advantage features of the magnetic nanoparticles and photoactive compounds were combined. The primary purpose of this work was the synthesis of magnetic nanoparticles coated with biocompatible and antitumor polysaccharide - levan, previously unknown from scientific literature, and the deposition of potent photosensitizer - zinc(II) phthalocyanine on their surface. In order to better characterize the nature of the coating covering the magnetic core, the atomic force microscope analysis, a contact angle measurement, and the mechanical properties of pure levan and its blend with zinc(II) phthalocyanine films were investigated. This magnetic nanomaterial revealed the ability to generate singlet oxygen upon exposure to light. Finally, preliminary toxicity of obtained nanoparticles was tested using the Microtox® test - with and without irradiation.