Nutrients, herbal bioactive derivatives and commensal microbiota as tools to lower the risk of SARS-CoV-2 infection

Abstract

The SARS-CoV-2 outbreak has infected a vast population across the world, causing more than 664 million cases and 6.7 million deaths by January 2023. Vaccination has been effective in reducing the most critical aftermath of this infection, but some issues are still present regarding re-infection prevention, effectiveness against variants, vaccine hesitancy and worldwide accessibility. Moreover, although several old and new antiviral drugs have been tested, we still lack robust and specific treatment modalities. It appears of utmost importance, facing this continuously growing pandemic, to focus on alternative practices grounded on firm scientific bases. In this article, we aim to outline a rigorous scientific background and propose complementary nutritional tools useful toward containment, and ultimately control, of SARS-CoV-2 infection. In particular, we review the mechanisms of viral entry and discuss the role of polyunsaturated fatty acids derived from α-linolenic acid and other nutrients in preventing the interaction of SARS-CoV-2 with its entry gateways. In a similar way, we analyze in detail the role of herbal-derived pharmacological compounds and specific microbial strains or microbial-derived polypeptides in the prevention of SARS-CoV-2 entry. In addition, we highlight the role of probiotics, nutrients and herbal-derived compounds in stimulating the immunity response.

Keywords: ACE-2; COVID-19; SARS-CoV-2; TMPRSS2; natural products; phytochemicals.

Figure 1

Schematic representation of intestinal mucosa exposed to SARS-CoV-2 infection (left panel) and positive effects of pro-and pre-biotic dietary supplementation (right panel). SARS-CoV-2 infection promote intestinal dysbiosis enhancing severity of the disease. Supplementation with probiotics and/or prebiotics is suggested as strategy to efficiently counteract the virus infection with better disease outcome. Created with BioRender.com.

Figure 2

Representation of the major cellular events that can be inhibited by natural products in contrasting SARS-CoV-2 infection. Their effects can limit the virus entry, directly interfering with cellular receptor binding (1), or indirectly changing the membrane fluidity (2), and/or can affect some pathways driven by virus. Intracellularly, involved mechanisms can be the downregulation of NF-kB, ACE2 or TMPRSS2 gene expression (3), the inhibition of cytokines release (4), to control the inflammatory process, and the downregulation of ACE2 and/or TMPRSS2 protein levels (5). AI, astersaponin I; BCP, β caryophyllene; EGCG, epigallocatechin gallate; GA, glycyrrhizic acid; PD, platycodin D; SB, Scutellaria barbata. Created with BioRender.com.