Chemical Constituents of Euphorbia sanctae-catharinae Fayed Essential Oil: a Comparative Study of Hydro-distillation and Microwave-Assisted Extraction

Objective: Microwave-assisted extraction (MAE), as an effective tool for the extraction of essential oil from medicinal and aromatic plants, has gained a great attention over the last years, thus in this study, MAE was performed to extract essential oils from aerial part of Euphorbia sanctae-catharinae. Methods: microwave-assistedextraction (MAE), as well ashydro-distillation (HD) techniques was used for oil preparation. Oil composition was studied by gas chromatography-mass spectrometry analysis.Results: Essential oil constituents and percentages of the obtained oils by MAE were compared with those obtained using conventional extraction HD technique. MAE offered reduction in the extraction time with better oil yield (1.2 % w/v) than that obtained when compared to HD(0.7 % w/v). Using MAE and HD for the extraction of E. sanctae-catharinae essential oil showed difference in the composition and percentage composition of the oil obtained with valencene (16.01%) and butyl hydroxy toluene (25.58%) being the major contents of the extracted oil using HD and MAE, respectively. Conclusion:To the best of our knowledge, this is the first study for the essential oil fromE. sanctae-catharinae. The tested essential oil samples did not show any significant antimicrobial activity at a concentration of 1 mg per disc.