The chemical compositions of eleven wild species of aromatic and medicinal plants indigenous to Algeria, including Thymus, Mentha, Rosmarinus, Lavandula, and Eucalyptus, were analyzed. The identification of the chemical composition of each oil was conducted using GC-FID and GC-MS capillary gas chromatography. The study investigated the chemical variability of the essential oils based on several parameters. These included the impact of the vegetative cycle on oil composition, variations among subspecies of the same species, variations among species within the same genus, the influence of environmental factors on composition variations within a species, chemo typing, and the genetic factors (such as hybridization) contributing to chemical variability. The concepts of chemotaxonomy, chemotype, and chemical markers were examined to understand their limitations and emphasize the importance of regulating the use of essential oils derived from wild plants. The study advocates for an approach that involves the domestication of wild plants and screening their chemical compositions according to more specific standards for each commercially available oil. Lastly, the nutritional implications and the variability of nutritional impact based on the chemical composition of the essential oils will be discussed.

Essential oils from the aerial parts of Anacyclus pyrethrum L. were analysed at three developmental stages (vegetative, floral budding and flowering). Oil yield was found to vary depending on the stage of development, and the highest content of oil (0.019% w/w) was obtained at flowering stage. The chemical composition of essential oils studied by GC and GC–MS showed a total of 91 compounds. Whatever the analysed stage is, oxygenated sesquiterpenes were the most abundant group. Their level significantly increased during ripening and varied from 37.1% to 58.6%. The oil showed activity against Candida albicans and Staphylococcus aureus bacteria strains. Thus, they represent an inexpensive source of natural antibacterial substances that may potentially be used in pathogenic systems.