Evaluating Microwave-Assisted Extraction of Elsholtzia Cristata Essential Oils: Efficiency, Chemical Profile and Antibacterial Activity

Background: This study evaluates the efficiency of essential oil extraction from Elsholtzia Cristata (EC) using two methods: the classical steam distillation method (CM) and the microwave-assisted extraction method (MM). The focus is on comparing these methods in terms of essential oil yield and assessing the antimicrobial properties of the extracted oils, particularly the antibacterial activity of citral. Objective: The study evaluates which extraction method yields higher essential oil content and bet-ter preserves bioactive compounds, with a focus on the antibacterial activity of citral. It also explores the potential pharmaceutical applications of the essential oil. Methods: Essential oils were extracted from EC using both CM and MM. The essential oil content was measured over different extraction times. Gas Chromatography-Mass Spectrometry (GC-MS) was used to identify the chemical constituents of the oils. Citral isolation efficiency was determined using bisulfite. Antimicrobial testing was performed to evaluate the antibacterial activity of EC essential oils against various bacterial strains. Results: The MM yielded a higher essential oil content (0.47% after 10 minutes) compared to CM (0.4% after 3 hours). GC-MS analysis identified citral A and citral B as the major components of the essential oil. The optimal molar ratio of citral to bisulfite for effective isolation was 1:3, achiev-ing an 86% efficiency. Both EC essential oil and citral exhibited strong antibacterial activity against a range of bacterial strains. Conclusion: The microwave-assisted extraction method demonstrated superior efficiency in ex-tracting essential oils from EC, with higher yields and shorter extraction times compared to the classical method. The significant antibacterial activity of EC essential oil indicates its potential for use in pharmaceutical and healthcare applications.