RSM-optimized extraction of essential oils from Pistacia lentiscus sap, leaves, and berries: Comparative study of composition and activity against gastric bacteria

Pistacia lentiscus essential oil is widely recognized for its gastroprotective and antimicrobial properties; however, there is no clear consensus on which plant part exhibits the strongest activity against Helicobacter pylori. The objective of this study was to compare essential oils extracted from leaves, berries, and sap in terms of extraction yield, chemical composition, and antibacterial activity. Essential oils were extracted, characterized by GC-MS, and evaluated for antibacterial activity against H. pylori strains J99 and F29, as well as Staphylococcus aureus, Escherichia coli, and Pseudomonas aeruginosa. The sap showed the highest yield (9.218%). GC-MS analysis revealed monoterpenes and sesquiterpenes as the main constituents, with α-pinene present in all samples. The leaf essential oil exhibited the strongest inhibition against H. pylori, exceeding the tested antibiotics against the F29 strain. These findings indicate that P. lentiscus leaves represent the most promising natural source for anti-H. pylori activity and suggest that the effect is due to synergistic interactions rather than α-pinene alone.