**5.3 Antiviral activity of miR2911 from plants**

According to the authors Zhou et al. [37], the repercussions, given by exogenous miRNAs from plants, together with the mechanisms involved in absorption and transfer "remain largely unknown". In their study they sequenced the plant honeysuckle (HS, *Lonicera japonica*) used for thousands of years to treat influenza infection and were able to obtain a total of 148 miRNAs in their reads. Additionally, the plant was subjected to a decoction process, finding only the MIR2911 stable after treatment, remaining in high concentrations (0.2 g HS/ml), was 0.06 pmol/ml suggesting its stability due to its sequence and high GC content. Subsequently, mice administered with the 500 μl decoction product of the plant reached a peak in the concentrations

#### *Effect in Human Gene Regulation of Food-Derived Plant miRNAs DOI: http://dx.doi.org/10.5772/intechopen.106366*

of MIR2911 in plasma and lung 6 h post-administration and a decrease to a basal level after 12 h. A series of potential target genes for MIR2911 of different viruses such as H1N1, H3N2, H5N1, and H7N9 were found through bioinformatic analysis. In cell lines infected with H1N1 and transfected with synthetic MIR2911, they achieved a significant decrease in viral count due to the fact that the target genes, PB2 and NS1, are essential for its replication. The in vivo study demonstrated that miR2911 inhibited the replication of several IAV (influenza A viruses) including H1N1, H5N1, and H7N9, decreasing mortality in mice, being the first evidence of a natural product that directly targets and suppresses IAV. In addition, the authors in 2020 conducted an emerging investigation of MIR2911, now against the SARS-CoV-2 virus, the cause of COVID-19, severe acute respiratory syndrome, which spread rapidly around the world, causing an unprecedented pandemic. Among the results, the researchers were able to inhibit viral replication in vitro, using exosomes from serum of donors who consumed the plant decoction and exosomes of synthetic MIR2911, showing a very high antiviral activity of plant MIR2911 on SARS-CoV-2 virus replication, since bioinformatics results showed at least 179 putative binding sites for the miRNA on the SARS-CoV-2 genome, with 28 binding sites subsequently confirmed, indicating that the plant miRNA could inhibit the translation of almost all SARS-CoV-2 proteins [38].
