Antibacterial and antioxidant activities of Pistacia lentiscus essential oils: Impact of total phenolic content on antioxidant efficacy

Abstract

Pistacia lentiscus, commonly known as mastic tree, has long been recognized for its medicinal properties and is a rich source of a wide range of bioactive compounds. This study investigates how geographic localization influences the variation in the chemical composition of Pistacia lentiscus essential oils (PLEOs) from three locations in Northern Morocco: Fnideq, Zinat, and Masmouda. It examines the total phenolic compound (TPC) content, antioxidant and antibacterial activities. The main compounds of PLEOs are α-pinene, limonene, β-myrcene, terpinen-4-ol, and α-sabinene with the percentages of 12.2–21.2%, 2.3–19.0%, 3.6–17.6%, 5.1–10.7%, and 1.4–9.1%, respectively. The PLEOs showed significant levels of TPCs and demonstrated strong antioxidant activity. Specifically, the PLEO from Fnideq exhibited the highest TPC content (89.23 ± 4.13) mg GAE/g EO and demonstrated effective radical scavenging activity with IC₅₀ values of (11.62 ± 1.07), (0.04 ± 0.01), and (4.64 ± 0.39) mg/mL in the DPPH, FRAP, and β-carotene model, respectively. Furthermore, a strong correlation was observed between TPCs and the antioxidant activity of all PLEOs. In terms of antibacterial activity, the Fnideq PLEO demonstrated the most significant inhibition against Listeria monocytogenes (26 ± 2) mm, while the Zinat sample showed notable effects against Staphylococcus aureus (14 ± 2) mm and Proteus mirabilis (14 ± 1) mm. Moreover, all PLEOs studied exhibited bactericidal effects at a concentration of 0.5 μl/mL. These findings highlight the potential of PLEO to address global challenges including antibiotic resistance, and underscore it use as a natural antioxidant and antibacterial agent, with promising applications as nutraceuticals.