Phytochemical characterization and preliminary antimicrobial evaluation of a mono- and sesquiterpene-rich essential oil of Salvia limbata C.A.Mey.

Understanding how chemotype and geographic origin influence essential oil composition and bioactivity is crucial for the identification of new plant-derived antimicrobials. In this study, the essential oil obtained from aerial parts of Salvia limbata C.A.Mey., collected in May 2023 in the Maragheh area (Kashan, Iran), was characterized and evaluated for its antimicrobial activity. The essential oil (0.16% w/w) was obtained by hydrodistillation and analyzed by GC–MS, identifying 45 compounds (99.97% of total content), mainly monoterpene hydrocarbons such as α-pinene (~19.32%), β-pinene (~13.62%), sabinene (~9.06%), along with bicyclogermacrene (~6.33%) and 1,8-cineole (~5.75%). Oxygenated compounds including linalool (5.2%) and (−)-spathulenol (5.6%) were also detected. The oil exhibited selective antibacterial activity against Acinetobacter baumannii (MIC 62.5 μg/mL; MBC 500 μg/mL) and moderate antifungal activity against Candida albicans (MIC/MFC 500 μg/mL), although its potency was lower than that of reference drugs. These findings highlight a previously unreported chemotype of S. limbata from the Kashan area and suggest a preliminary baseline antimicrobial potential associated with its volatile terpene composition. As a preliminary screening study, further multi-centric investigations, including precise mechanistic assays, comprehensive cytotoxicity evaluations, and in vivo validations, remain essential to fully ascertain its translatational and biomedical applications.