**6. Antiviral therapeutics**

Numerous antiviral drugs inhibiting influenza viruses are available. The most targeted sites for restricting influenza viruses are matrix protein 2 and NA, inhibited by antivirals such as adamantanes (amantadine and rimantadine), oseltamivir, and zanamivir [28]. The adamantanes interfere with viral uncoating and had shown toxic effects that lead to the generation of adamantanes-resistant strains of the influenza virus. Furthermore, the budding off progeny virions from host cells is impeded by the neuraminidase inhibitors that caused only one round of replication, hence preventing the spread of infection. Influenza viruses such as influenza A(H3N2) and A(H1N1)pdm09 were observed to be resistant for adamantanes; therefore, for the clinical treatment of influenza virus A, adamantanes are not recommended. However, IAV and influenza B virus are susceptible to oseltamivir and zanamivir [29]. The other potential targeted sites are viral entry, HA, pH-dependent endosomal fusion, nucleoproteins and polymerase proteins of influenza viruses. HA1 and HA2 play key roles in the invasion of the influenza virus in target host cells. HA1 binds with the sialic acid receptors while HA2 contributes in the fusion and internalization by endocytosis. Furthermore, a novel antiviral N-stearoyllipopeptide of C18-ARLPR inhibits the viral replication of influenza A/Puerto Rico/8/34 (H1N1) and A/Aichi/2/68 (H3N2) effectively with low toxicity [30]. This peptide adequately binds to the sialic acid-binding site of HA1 subunit due to its structural similarity.
