Broad Spectrum Algae Compounds Against Viruses

Abstract

The pharmaceutical industry is currently trying to develop new bioactive compounds to inactivate both enveloped and non-enveloped viruses for therapeutic purposes. Consequently, microalgal and macroalgal bioactive compounds are being explored by pharmaceutical, as well as biotechnology and food industries. In this review, we show how compounds produced by algae include important candidates for viral control applications. We discuss their mechanisms of action and activity against enveloped and non-enveloped viruses, including those causing infections by enteric, parenteral, and respiratory routes. Indeed, algal products have potential in human and animal medicine.

Keywords: algae; antiviral; health; mechanisms; virucidal.

FIGURE 1

The mechanisms of the action of natural compounds can be divided into two phases: before and after viral entry. 1-A: GRFT Protein from the Griffithsia sp. macroalgae binds to specific oligosaccharides in the virus envelope glycoproteins and block viral entry (O’Keefe et al., 2010). 1-B: Polysaccharides from Laminaria japonica enhance the expression level of IRF3 and the secretion of IFN alpha that results an antiviral activity against RSV. 1-C: The binding of HMPV to heparan sulfate involves charge-charge interactions; this blocks the binding of HMPV to the receptor and consequently inhibits the infection of cells (Klimyte et al., 2016) 0.1-D: Iota-carrageenan from red algae has a long chain of negatively charged molecules that attract and capture positively charged viruses and prevent them from infecting cells (Leibbrandt et al., 2010; Eccles, 2020). 1-E: Iota-carrageenan binds to the surface of rhinovirus and inhibits virus binding to cell receptors (Grassauer et al., 2008). 2-A: Viral entry. 2-B Iota-carrageenan also has an inhibitory effect after the virus enters the cell, blocking the conformational changes of rhinovirus necessary for infection (2-B: uncoating and 2-C: replication) Iota-carrageenan acts occludes virion surfaces involved in binding to cellular proteins required for the infectious process; this prevents replication and results in the viral particles produced being defective (Buck et al., 2006; Grassauer et al., 2008). 2-D: Exit of defective viral particles.