Copper Gluconate – An Ally Against Respiratory Viruses

Autumn and winter are two seasons in which there is a drop in environmental temperatures, with consequent proliferation of respiratory viruses and development of airway diseases such as flu, colds and bronchitis.

To date, there are many preventive strategies for respiratory viruses and they are based on the use of products containing active ingredients with strong antiviral action.

Among these, copper gluconate (copper salt in its orally bioavailable form) is particularly useful as a preventive and adjuvant strategy in the therapy of respiratory viruses and the bacterial complications associated with them, as it has both antiviral and antibacterial activity.

Copper - What it is and its benefits

Copper, an essential mineral, is naturally present in some foods and is essential in our body for various physiological processes, and in particular:

• It is a cofactor for enzymes involved in iron metabolism, connective tissue synthesis, and neurotransmitter synthesis.
• It is involved in the functioning of the immune system. Several studies have found that copper deficiency results in a weakened immune response in humans. Copper serves as an important factor in the proper functioning of B cells, helper T cells, natural killer (NK) cells, neutrophils, and macrophages, all of which are essential immune cells.
• It is involved in defense systems against oxidative stress, such as the enzyme superoxide dismutase.

In addition to these properties, copper has been used in medicine as an antimicrobial agent since the times of the Egyptians and ancient Greece. In fact, it has the ability to kill viruses and bacteria through direct contact. This means that if a bacterium or virus comes into contact with an adequate concentration of copper, it is killed.

In 2008, the U.S. Environmental Protection Agency (EPA) recognized copper as the first metallic antimicrobial agent, noting that a copper surface can kill 99.9% of pathogenic bacteria within 2 hours.

The antiviral activity of copper has been well demonstrated by several studies. For example, a study by Noyce et al., highlighted the antiviral properties of copper against influenza A virus, inoculating virus particles on a copper surface. It was seen that, after 6 hours, very few active viral particles remained on the copper surface.

These results were confirmed by another study, carried out by Borkow et al., which demonstrated that copper oxide impregnation in respiratory protective face masks confers biocidal properties against human and avian influenza A viruses without altering the physical barrier properties of the mask.

The study found that after just 30 minutes, there were no traces of infectious viral particles in the masks containing copper oxide, unlike the control masks.

Copper against Covid-19

The exact antiviral mechanism of copper is not yet well known but it is thought that it is able to degrade viral proteins and DNA by inducing oxidative stress and destroying viral structures.

In particular, copper would be able to destroy the external envelope of the virus (the capsid), and the viral DNA, preventing the replication and spread of the virus. Copper can bind directly to viruses and damage the capsids by physical means or chemical interactions caused by the generation of toxic species such as, for example, reactive oxygen species (ROS) powerful oxidizing substances.

Recent studies conducted on the Sars CoV2 virus have shown how copper, in its copper gluconate form, attenuates SARS-CoV-2 infection in vitro, with a 71% reduction in the rate of cellular infection.

However, it was noted that the antiviral effect of copper against Sars Cov2 was inhibited by albumin, which suggests that if copper is administered systemically, it may not be effective in fighting the infection.

Therefore, it is hypothesized that copper gluconate may be beneficial when administered topically, that is, directly in contact with the nasal mucosa, for example in the form of a nasal gel.

References

- http://www.epa.gov/pesticides/factsheets/copper-alloy-products.htm

- Vincent M, Duval RE, Hartemann P, Engels-Deutsch M. Contact killing and antimicrobial properties of copper. J Appl Microbiol. 2018 May;124(5):1032-1046.

- Rodriguez K, Saunier F, Rigaill J, Audoux E, Botelho-Nevers E, Prier A, Dickerscheit Y, Pillet S, Pozzetto B, Bourlet T, Verhoeven PO. Evaluation of in vitro activity of copper gluconate against SARS-CoV-2 using confocal microscopy-based high content screening. J Trace Elem Med Biol. 2021 Dec;68:126818.

- Govind V, Bharadwaj S, Sai Ganesh MR, Vishnu J, Shankar KV, Shankar B, Rajesh R. Antiviral properties of copper and its alloys to inactivate covid-19 virus: a review. Biometals. 2021 Dec;34(6):1217-1235.

- Ermini ML, Voliani V. Antimicrobial Nano-Agents: The Copper Age. ACS Nano. 2021 Apr 27;15(4):6008-6029.

- Noyce, JO, Michels, H. and Keevil, CW (2007) Inactivation of influenza A virus on copper versus stainless steel surfaces. Appl Environ Microbiol 73, 2748–2750.

- Borkow, G., Zhou, SS, Page, T. and Gabbay, J. (2010) A novel anti-flu copper oxide containing respiratory face mask. PLoS ONE 5, e11295.