Microwave accelerated distillation of essential oils from the leaves of eucalyptus microtheca: Optimization and comparison with conventional hydrodistillation

Abstract

In recent years, a novel technique has been developed for the extraction of natural products of plants based upon exertion of microwave energy at atmospheric pressure namely microwave assisted extraction. Microwave accelerated distillation (MAD) was applied for the extraction of essential oil from the leaves of Eucalyptus microtheca. The microwave assisted extraction method has been compared with hydrodistillation (HD) conventional technique, in terms of extraction time, yields and chemical compositions. Also, effect of microwave powers were investigated on extraction of some major constituents of E. microtheca essential oil. The obtained results show that, the extraction of essential oils from Eucalyptus by microwave assisted extraction is more efficient rather than hydrodistillation especially from yield and time of extraction points of view (10 min versus 3 h and 1.72 % versus 0.29 %). The extracted essential oils involved 18 and 34 components constituting 94.04 and 89.07 % of the chemical profiles in the hydrodistillation and microwave assisted extraction methods, respectively. The results also show that, each type of Eucalyptus microtheca essential oil compounds has an optimum microwave power for efficient extraction and this power should be used to enhance useful components of essential oil and to save energy.