In Vitro Influenza A Virus-Inactivating Activity of HIDROX^®, Hydroxytyrosol-Rich Aqueous Olive Pulp Extract

Area of Science:

• Virology
• Natural Product Chemistry

Background:

• Influenza A virus (IAV) poses a significant global health threat as a respiratory pathogen.
• Developing effective and safe antiviral strategies is crucial for managing IAV infections.

Purpose of the Study:

• To evaluate the influenza A virus (IAV)-inactivation capacity of a hydroxytyrosol (HT)-rich olive pulp extract (HIDROX).
• To elucidate the mechanisms underlying the antiviral activity of HIDROX and its active component, HT.

Main Methods:

• Assessing virucidal activity of HIDROX and HT in solution and cream formulations.
• Utilizing Western blotting (WB) to analyze viral structural protein changes.
• Evaluating effects on hemagglutination, neuraminidase activity, viral genome, and particle morphology via electron microscopy.
• Investigating the role of reactive oxygen species (ROS) and reactive nitrogen species (RNS) in antiviral mechanisms.

Main Results:

• HIDROX exhibited concentration- and time-dependent virucidal activity against IAV, surpassing that of pure HT.
• WB analysis revealed structural abnormalities and high-molecular-mass bands in viral proteins after HIDROX and HT treatment.
• HIDROX and HT showed minimal impact on hemagglutination, neuraminidase activity, viral genome, and particle structure.
• Only HT, not HIDROX, induced significant ROS/RNS production, which was linked to its virucidal effect and protein abnormalities.

Conclusions:

• HIDROX possesses significant influenza A virus (IAV)-inactivating properties, potentially through mechanisms independent of ROS/RNS.
• The study highlights the potential of HIDROX as a naturally derived antiviral agent for IAV control.
• Further research into HIDROX's specific molecular targets could lead to novel therapeutic strategies against influenza.