With the current outbreak of coronavirus disease, it’s not surprising people are looking for ways to boost their immune system, and since there is no vaccine yet, it’s all we can do (besides minimising risks of contamination). We came across a number of studies conducted that might make your search of natural foods to boost your immune system a bit easier:
 

Anti-influenza virus activity of Blackcurrants

In one study the Department of Microbiology, at the Medical University School of Medicine, in Fukushima, Japan has researched the inhibitory effect of extracts of blackcurrant from New Zealand and Poland on 4 strains of influenza virus (IFV)  by the inhibition of virus adsorption; pandemic flu 2009-2010, Hong Kong flu, Russian flu and influenza virus type B.

The inhibitory effect of the extracts of blackcurrant or blueberry on the infectivity of the virion was evaluated by the inhibition of virus adsorption on the cell surface (adsorption-inhibitory assay). Three per cent solutions of the blackcurrant extracts from New Zealand and Poland were enough to disinfect more than half of pandemic flu and influenza virus type B, and 10% solutions from both regions disinfected all IFV strains completely.

Their previous study showed that the antiviral effect of the blackcurrant differed according to viral species. Here they showed that although the antiviral effect of Blackcurrant was slightly different within viral strains from one species, the extract of Blackcurrant could disinfect all of 4 IFV strains they examined. The extracts of blackcurrant showed definite potential for use as a disinfectant and antiseptic agent to prevent IFV infection. Check out the full study here.

Ārepa contains over 140 New Zealand Blackcurrants and 300mg of blackcurrant anthocyanins in every bottle

This study showed that treatment of cultured cells with blackcurrant extract in the laboratory protected them from infection by an influenza virus. Fractionation of blackcurrant extract has found that polyphenols are responsible for the observed antiviral activity. The compounds act by inhibiting haemagglutinin function. Haemagglutinin is the molecule on the surface of viral particles that binds the virus to cells it is infecting

Two studies [1] [2] showed blackcurrant extract to possess antiviral activity. In one in vitro experiment, it was found that cells infected by influenza virus type A (IVA) or influenza virus type B (IVB) had their rate of infection almost stopped when blackcurrant extract was applied. In another experiment, addition of virus and extract simultaneously to cells resulted in infection rates 2 - 5% of that observed when only virus was added. Mice fed extract exhibited reduced virus accumulation and improved mortality Fractionation of extract demonstrated antiviral activity is possessed by the polyphenol containing fraction. Polyphenols act on haemagglutinin, inhibiting a virus’s ability to infect a cell and reproduce within it. (Haemagglutinin is the molecule on the surface of viral particles that binds the virus to cells it is infecting.)

Results of other studies [3] [4] showed that the total extracts of all tested berry fruits inhibit the replication of CV-B1 and influenza A virus (1) and that blackcurrant can produce anti-inflammatory effects due to Cyanidin-3-O-glucoside, and anti-influenza properties when prepared as the extract.(2)

Another study revealed the potential of anthocyanin to show its antiviral effects through binding to host cells, inhibiting viral life cycle, or stimulating host immunity, strengthens the idea that anthocyanin would be an essential brick and a potential therapeutic agent to find novel antiviral lead-compounds. Altogether, the blackcurrant extracts displayed auspicious anti-InfV effects through different mechanisms.

Lastly, this study tested Jamaican Sorrel, Blackcurrant Berries, and Manuka Honey paired with Bee Pollen for antiviral activity. They demonstrated that these nutraceuticals blocked the 2009 Pandemic California Influenza strain between a concentration range of 1:8-1:16 dilution.

To read more on the effects of the New Zealand blackcurrant, check out our blog on The extremely high levels of Vitamin C in New Zealand Blackcurrants.