Phytochemical Characterization of <i>Olea europea</i> Leaf Extracts and Assessment of Their Anti-Microbial and Anti-HSV-1 Activity

• Main Authors: Ichrak Ben-Amor, Maria Musarra-Pizzo, Antonella Smeriglio, Manuela D’Arrigo, Rosamaria Pennisi, Hammadi Attia, Bochra Gargouri, Domenico Trombetta, Giuseppina Mandalari, Maria Teresa Sciortino
• Format: Article
• Language: English
• Published: MDPI AG 2021-06-01
• Series: Viruses
• Subjects: <i>Olea europea</i> L.; LC-DAD-ESI-MS analysis; antimicrobial effect; antiviral activity; herpes simplex virus 1
• Online Access: https://www.mdpi.com/1999-4915/13/6/1085

Owing to the richness of bioactive compounds, <i>Olea europea</i> leaf extracts exhibit a range of health effects. The present research evaluated the antibacterial and antiviral effect of leaf extracts obtained from <i>Olea europea</i> L. var. <i>sativa</i> (OESA) and <i>Olea europea</i> var. <i>sylvestris</i> (OESY) from Tunisia. LC-DAD-ESI-MS analysis allowed the identification of different compounds that contributed to the observed biological properties. Both OESA and OESY were active against Gram-positive bacteria (MIC values between 7.81 and 15.61 μg/mL and between 15.61 and 31.25 μg/mL against <i>Staphylococcus aureus</i> ATCC 6538 for OESY and OESA, respectively). The antiviral activity against the herpes simplex type 1 (HSV-1) was assessed on Vero cells. The results of cell viability indicated that <i>Olea europea</i> leaf extracts were not toxic to cultured Vero cells. The half maximal cytotoxic concentration (CC₅₀) values for OESA and OESY were 0.2 mg/mL and 0.82 mg/mL, respectively. Furthermore, both a plaque reduction assay and viral entry assay were used to demonstrate the antiviral activity. In conclusion, <i>Olea europea</i> leaf extracts demonstrated a bacteriostatic effect, as well as remarkable antiviral activity, which could provide an alternative treatment against resistant strains.