Chemical composition, kinetic study and antimicrobial activity of essential oils from Cymbopogon schoenanthus L. Spreng extracted by conventional and microwave-assisted techniques using cryogenic grinding

In this present work, volatile oils from Cymbopogon schoenanthus L. Spreng's (CS) leaves extracted by microwave assisted hydrodistillation (MAHD) and microwave assisted steam distillation (MASD) were studied according to simple (SG) and cryogenic grinding (CG) and compared with conventional hydrodistillation (HD). Extraction time, kinetics, energy consumption, CO2 rejected, physical properties, chemical composition and antimicrobial activity were investigated for the first time with this specie using microwave extraction and showed that MAD is a promising and innovative technique for extraction of volatile oils; also, cryogenic grinding allowed a high extraction yield compared to the classical grinding (MAHD-CG: 1.76% - MAHD-SG: 1.25%) and (MASD-CG: 1.5% - MASD-SG: 1.11%). GC and GC-MS analysis showed variability in composition according to the technique used especially in major constituents and in chemical classes. Qualitative and quantitative kinetic study demonstrated a significative effect of extraction technique and grinding mode on aromatic profile. Evaluation of antimicrobial activity showed that the efficiency of volatiles from CS varied according to extraction technique used where MASD-SG volatile was the most effective one.