Chemical profiling and antibacterial evaluation of essential oils from Pistacia falcata Becc. ex-Martelli

The chemical composition of essential oils extracted from various parts of Pistacia falcata Becc. ex-Martelli including inflorescences, fruiting inflorescences, roots, and leaves was analysed. The essential oils revealed a dominance of monoterpene hydrocarbons, ranging from 74.6% to 94.5%. The dominant monoterpene hydrocarbon was α-pinene in the roots (80.4%), followed by myrcene in the leaves (45.1%). Oxygenated monoterpenes ranged from 1.0% to 9.0%, with bornyl acetate being the most prominent (4.8%) in the inflorescence. Sesquiterpene hydrocarbons were present in amounts ranging from 0.0% to 7.1%, with bicyclogermacrene being the major constituent (2.4%) in the inflorescence. Oxygenated sesquiterpenes ranged from 0.1% to 7.2%, with (E)- nerolidol being the most abundant in the roots. The antibacterial activity of these oils was assessed against Staphylococcus aureus NCTC 6571, Escherichia coli MG1655, and Pseudomonas aeruginosa PAO1. Minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) assays revealed moderate activity of the inflorescence and fruiting inflorescence oils against S. aureus (MIC and MBC=5 mg/mL). Leaf oil showed moderate activity (MIC=10 mg/mL), while root oil was inactive (MIC>20 mg/mL). No inhibition was observed against E. coli or P. aeruginosa , although pigment alterations in P. aeruginosa were noted at 5-10 mg/mL. Growth kinetics confirmed sustained inhibition by the inflorescence oil over 24 hours at 5 mg/mL. However, biofilm formation by P. aeruginosa was not significantly affected. These results highlight the moderate antibacterial potential of P. falcata floral essential oils, particularly against Gram-positive bacteria [ 1 ]. Publication History Article published online: 05 March 2026 © 2026. Thieme. All rights reserved. Georg Thieme Verlag KG Oswald-Hesse-Straße 50, 70469 Stuttgart, Germany