comparison of microwave-assisted and hydrodistillation methods for extraction of essential oil from achillea millefolium

microwave-assisted hydrodistillation (mahd) method has been compared with hydrodistillation (hd) conventional technique for extraction of essential oil from achillea millefolium. microwave-assisted hydrodistillation were examined at three levels of microwave powers (300, 500, and 700 w) .   obtained results show that   mahd offers important advantages over hd in terms of energy savings and extraction time (20 min against 2.5 h). also, the essential oils were analyzed by gc-ms. the amount of oxygenated compounds and monoterpene, such as 1,8 -cineole, lavandulyl acetate,caryophylla-dien, aromadendrene were increased in the microwave method. all these results suggest that mahd represents an excellent alternative method for extraction of essential oils from plant materials.