EFFECT OF ULTRASOUND PRETRAITMENT ON THE QUALITY AND ANTIMICROBIAL ACTIVITY OF ESSENTIAL OILS FROM FOUR WILD POPULATIONS OF ALGERIAN LAVANDULA STOECHAS L.: COMPARISON WITH CONVENTIONAL HYDRODISTILLATION
This work presents the influence of ultrasound pretreatment of Lavandula stoechas on the extraction process of essential oils (EOs), compared with conventional hydrodistillation (HD). This study aims to improve the green techniques for obtaining EOs from aromatic and medicinal plants.
The tests were carried out on L. stoechas harvested from 04 sites in the north of Algeria. These samples were pretreated by sonication times of 10, 20, 30, 45 and 60min followed by 90min of HD (US-HD) and compared with untreated samples (180min of HD) in terms of extraction duration, yield, quality, chemical composition and antimicrobial activity of EOs.
10min of pretreatment time gives yields of 1.60% and 1.59% of Kodiat and Adekar EO’s, respectively. This pretreatment time proved to be the best compared with the other pretreatment times. The US-HD yields are higher compared to those obtained by HD for the four samples. The US-HD EO’s has a darker color and a more intense odor compared with HD EO’s. GC/MS analysis showed a qualitative and quantitative difference in the chemical composition of treated and untreated samples. Our extracts showed good antimicrobial activity against most of the 08 pathogenic strains tested. This antimicrobial potential remains more interesting in the US-HD case.