The effect of some ecological characteristics (climate, soil, water content, and altitude) on the quality and antibacterial activity of Stachys inflata Benth. essential oil based on the indigenous knowledge of Iranian people

Stachys inflata Benth. (Lamiaceae) is a critically important medicinal species in traditional Iranian medicine, yet the precise ecological drivers of its phytochemical plasticity and therapeutic efficacy remain poorly understood. This study provides a comprehensive investigation into how multi-dimensional ecological factors—including altitude, soil physicochemical properties, water content, and climate—influence the essential oil profile and antibacterial potency of S. inflata across seven distinct habitats in Kashan, Iran. For the first time, we bridge indigenous pharmacological knowledge with systematic ecological modeling to identify optimal environmental niches for industrial harvesting. The selection of target pathogens was strategically guided by indigenous pharmacological knowledge regarding the plant's traditional use in treating skin and respiratory infections. The flowering tops of the plant were harvested in late May 2023. The essential oil was extracted using a Clevenger apparatus and its components were analyzed using a GC-MS apparatus. The antibacterial activity of different essential oils against selected strains ( Pseudomonas aeruginosa and Staphylococcus aureus ) was determined by measuring the zone of inhibition, minimum inhibitory concentration, and minimum lethal concentration. Results showed that soil EC and silt content function as primary determinants of essential oil yield, which reached its maximum in the Maragheh area (1.62%). GC-MS analysis revealed remarkable chemotypic variation, identifying phenol (0–25.03%) and β-copaene (0.22–66%) as dominant constituents—a novel finding for this region. While all samples were ineffective against P. aeruginosa , the essential oil from the Imamzadeh Shahsavaran area exhibited moderate antibacterial activity against S. aureus (19.5 mm inhibition zone). These results scientifically validate the traditional use of S. inflata for skin infections and demonstrate that its bioactive potential is strictly governed by soil water capacity and altitude. This work offers a strategic roadmap for the pharmaceutical industry to optimize the standardized production of S. inflata essential oils by targeting specific ecological niches .