Hydrodistillation wastewaters from essential oils industry: a source of biologically active phytocomplexes with potential pharmaceutical and nutraceutical applications

During the distillation process for essential oils production a variable, but significant, amount of wastewaters (DWWs) is produced, which are not yet addressed to any further application. DWW obtained from medicinal aromatic plants (MAPs) distillation can be likened to the product of a hot aqueous extraction, therefore rich in water-soluble metabolites with potential biological application once recovered as reccomended by “European green deal” waste hierarchy, which prioritizes reuse and recycling.The scope of our ij progress work is to evaluate the phenolic composition of wastewaters coming from hydrodistillation of several MAPs belonging to the Labiatae family as well as to assess their potential biological activities for their exploitation in the pharmaceutical and nutraceutical fields. Our first results showed that DWWs contain high amounts of phenolic compounds [ 1 ] [ 2 ] such as organic acids, flavones and flavonols. Preliminary biological activity studies conducted highlighted the anti-inflammatory activity in intestinal epithelial cells [ 1 ] and on murine macrophage cells in vitro models and the inhibitory activity against α-Glucosidase and α-Amylase of these phytocomplexes [ 3 ]. Probiotic and antimycotic activity of oregano DWW has been also investigated. Our results suggest that growth and metabolic activity of probiotic Lactobacillus spp. were stimulated by oregano DWW. Also in presence of both Lactobacilli spp. and oregano DWW the growth of Candida albicans (an opportunistic pathogen) was significantly inhibited siggesting the potential use of DWWs in candidiasis prophylaxis and therapy. Although further studies are needed, our results open new possibilities for the use of MAPs DWW in the pharmaceutical, nutraceutical and food fields. Publication History Article published online: 05 March 2026 © 2026. Thieme. All rights reserved. Georg Thieme Verlag KG Oswald-Hesse-Straße 50, 70469 Stuttgart, Germany