Abstract
The chemical composition of the essential oils was influenced by many factors including extraction methods. In this study, the effect of extraction methods; hydrodistillation, microwave assisted hydrodistillation and solvent free microwave extraction of Mentha piperita L. growing in Taif, KSA, on the yield and chemical composition of their essential oils were investigated. Furthermore, the oils were in vitro investigated as antimicrobial and anticancer agents. The results showed no great difference between the oil yields obtained by the three different methods but the methods which used microwave were rapid, saving time and energy than classical hydrodistillation. The qualitative chemical compositions of the oils were similar with little quantitative differences of some compounds between the three methods. All oils consists mainly of monoterpenes and sesquiterpenes in which carvone is the main component of M. piperita (carvone chemotype). All essential oils showed moderate in vitro anticancer activity and high antimicrobial activity. In conclusion, this considered to be the first study represented the effect of microwave extraction on the essential oil chemical composition of M. piperita growing in Taif, KSA. The authors recommended the usage of microwave method in the extraction of essential oils because it is energy and time saving, in addition to environment friendly.