In a U.S. patent, it has been claimed that Oleuropein has potent antiviral activities against herpes mononucleosis, hepatitis virus, rotavirus, bovine rhinovirus, canine parvovirus, and feline leukemia virus [1]. Studies have also shown that Oleuropein exhibits a significant antiviral activity against respiratory syncytial virus and para-influenza type 3 virus [2]. There is also one anecdotal report that olive leaf extracts augment the activity of the HIV-RT inhibitor 3TC [3]. The olive leaf extracts were investigated for their antiviral activity against viral hemorrhagic septicemia virus (VHSV), a salmonid rhabdovirus, and against HIV-1 infection and replication [4]. Cell-to-cell transmission of HIV was inhibited in a dose-dependent manner with EC50s of 0.2 µg/ml, and HIV replication was inhibited in an in vitro experiment [5]. One of the suspected targets for olive leaf extract (mainly Oleuropein) action is HIV-1 gp41 (surface glycoprotein subunit), which is responsible for HIV entry into normal cells. In order to establish HIV protein targets of olive leaf extract and its inhibitory action at the molecular level, Lee-Huang et al. [6] reported a joint theoretical and experimental effort has been carried out to help achieve this goal.

SEE POTENTIAL COVID-19 INHIBITORS STUDY
• Potential Inhibitor of COVID-19 Main Protease (Mpro) From Several Medicinal Plant Compounds by Molecular Docking Study
• 1. Fredrickson, WR, F and S Group, Inc.
  Method and Composition for Antiviral Therapy with Olive Leaves. U.S. Patent. 2000; 6: 117:884.
• 2. Ma SC, He ZD, Deng XL, But PP, Ooi VE, Xu HX, Lee SH, Lee SF.
  In vitro evaluation of secoiridoid glucosides from the fruits of Ligustrum lucidum as antiviral agents.
  Chem Pharm Bull. 2001; 49: 1471–1473. doi:10.1248/cpb.49.1471
• 3. Walker M.
  Olive leaf extract. The new oral treatment to counteract most types of pathological organisms.
  Explore: The Journal of Science and Healing. 1996; 7: 31.
• 4. Micol V, Caturla N, Perenz-Fons L, Mas L, Perez L, Estepa A.
  The olive leaf extract exhibits antiviral activity against viral haemorrhagic septicaemia rhabdovirus (VHSV).
  Antivir Res. 2005; 66: 129–136. doi:10.1016/j.antiviral.2005.02.005
• 5. Lee-Huang S, Zhang L, Chang YY, Huang PL.
  Anti-HIV activity of olive leaf extract (OLE) and modulation of host cell gene expression by HIV-1 infection and OLE treatment.
  Biochem Biophys Res Commun. 2003; 307: 1029–1037. doi:10.1016/S0006-291X(03)01292-0
• 6. Lee-Huang S, Huang PL, Zhang D, Lee JW, Bao J, Sun Y, Chang YT, Zhang J, Huang PL.
  Discovery of small-molecule HIV-1 fusion and integrase inhibitors Oleuropein and Hydroxytyrosol:
  Part I. Integrase Inhibition. Biochem Biophys Res Commun. 2007; 354: 872–878. doi:10.1016/j.bbrc.2007.01.071
• Discovery of Small-Molecule HIV-1 Fusion and Integrase Inhibitors Oleuropein and Hydroxytyrosol: I. Fusion Inhibition
• Computational study of bindings of olive leaf extract (OLE) to HIV‐1 fusion protein gp41
• Antiviral efficacy against hepatitis B virus replication of oleuropein isolated from Jasminum officinale L. var. grandiflorum.
• Effects of the Olive-Derived Polyphenol Oleuropein on Human Health
• Oleuropein: Molecular Dynamics and Computation
• On the In-Vitro Antimicrobial Activity of Oleuropein and Hydroxytyrosol