Effect of Geographical Location and Extraction Methods on the Chemical Composition and Antimicrobial Activity of Cotula cinerea Essential Oil via Chemo-Metric Analysis.

This study evaluated how geographical origin (El Alamein vs. Red Sea regions in Egypt) and extraction methods saffect the chemical profile and antimicrobial efficacy of Cotula cinerea essential oils. Comparing conventional hydro-distillation (HD) to microwave-assisted extraction (MAE), researchers found that MAE delivered higher oil yields (0.35%-0.37%) than HD (0.31%-0.34%) in significantly less time. Gas chromatography-mass spectrometry (GC/MS) identified 19 volatile compounds-predominantly oxygenated monoterpenes like pinocarvone, α-thujone, and camphene-with statistical analyses confirming that both location and extraction technique distinctly altered this chemical composition. Furthermore, MAE-extracted oils demonstrated superior antimicrobial activity, particularly those from El Alamein, which reached a notable 25 mm inhibition zone against Aspergillus niger. Ultimately, the results indicate that MAE is a highly efficient and reproducible method for harvesting bioactive C. cinerea oils for potential pharmaceutical and nutraceutical applications.