Extraction Method That Enriches Phenolic Content in Oregano (Lippia Graveolens H.B.K.) Essential Oil

The aim of this work was to evaluate a method that enriches the phenolic content in the essential oil of oregano, by obtaining high and constant phenolic concentrations. By means of extractive techniques such as fractional distillation, it was possible to concentrate thymol and carvacrol, as high as 74% in one essential oil fraction. In addition, the influence of the source region of the oregano on the phenolic content in the essential oil obtained by fractional hydrodistillation was also investigated; however, no significant effect was found ( P > 0.05) based on source region. It may be considered that the fractional hydrodistillation method standardizes the phenolic content in essential oil composition regardless of the source of the spice. In this way, this method enriches phenolic content and reduces the effect of variable environmental factors on the quality of essential oils of oreganos from three different Mexican states. PRACTICAL APPLICATIONS The present investigation was carried out to improve the traditional extraction method for essential oils. With a few modifications, this method allows the fractionation of oregano essential oil in a 50:50 ratio, obtaining two fractions with high phenolic content; phenols are responsible for microbicide properties of the essential oil of oregano. This is an important step, considering the variability in phenolic content found in this spice, and because almost all of the harvested oreganos in Mexico contain a 45–50% average phenolic content. This method is attractive because it enriches the phenolic content in the essential oil and reduces environmental factors that affect oregano's essential oil, thus improving the quality of the essential oil of oregano. The contributions of the present work are to increase knowledge in the field of aromatic herbs, to enhance the economic advantages of Mexican oregano and to propose alternative applications for use, such as novel microbicide ingredients in the development of natural food products.