Extraction of Essential Oil from Origanum Majorana and Evaluation of Its Antimicrobial Activity Against Pathogenic Bacteria Isolated from a Hospital Environment

Abstract

This study aimed to develop an efficient and low-cost method for extracting essential oil from Origanum majorana (marjoram) and to evaluate its antimicrobial activity against pathogenic bacteria isolated from a hospital environment. An organic solvent extraction method using n-hexane at a controlled low temperature (35 °C) was employed to preserve thermolabile bioactive compounds while reducing energy consumption. The extraction process involved plant drying, solvent maceration, purification, and the production of absolute oil through vacuum distillation. The antimicrobial activity of both commercially available and naturally extracted marjoram essential oils was assessed against bacterial isolates obtained from different hospital departments, including nephrology, maternity, intensive care, and neonatal units. The disc diffusion method described by Lorian (1980) was used to evaluate bacterial sensitivity. A total of 250 bacterial isolates were obtained from 160 clinical and environmental samples. The results demonstrated that the naturally extracted marjoram essential oil exhibited notable antibacterial activity, particularly against Proteus mirabilis, Escherichia coli, and Staphylococcus aureus. Inhibition zones increased proportionally with oil concentration, reaching the highest values at 30%. In contrast, commercial marjoram oils showed limited or no antibacterial efficacy, which may be attributed to low concentrations of active compounds or improper manufacturing and storage conditions. The study concludes that the proposed low-cost solvent extraction method yields high-quality essential oil with significant antibacterial properties. Origanum majorana essential oil represents a promising natural alternative for pharmaceutical and therapeutic applications, especially in the context of combating hospital-associated bacterial pathogens.