Origanum vulgare L. is a well-known aromatic and medicinal plant, whose essential oil (EO) has recognised flavouring and medicinal properties. In this study, Origanum vulgare subsp. virens (Hoffmanns. & Link) Ietsw. EOs, isolated from accessions grown in experimental fields, were evaluated. The plant material was grown from rooted cuttings or nutlets (fruits), originally collected in 20 regions in mainland Portugal and harvesting for EO isolation was performed in two years. EOs were isolated by hydrodistillation and analysed by gas chromatography and gas chromatography–mass spectrometry, for EO quantification and identification, respectively. EO yields ranged from <0.05–3.3% for rooted cuttings, with oregano samples obtained in Portalegre and Alandroal, respectively. Ninety-one compounds were identified, mainly grouped in oxygen-containing monoterpenes and monoterpene hydrocarbons. EO agglomerative cluster analysis evidenced two main clusters, with the first subdivided into four subclusters. From the obtained data, the putative O. vulgare subsp. virens chemotypes are carvacrol, thymol and linalool, with γ-terpinene, p-cymene, cis- and trans-β-ocimene also contributing as these EOs chemical descriptors. The comparison between the present data and a survey of the existing literature on Portuguese O. vulgare reinforces the major variability of this species’ EOs and emphasises the importance of avoiding wild collections to obtain a defined chemical type of crop production of market relevance.

Coriander is a medicinal and aromatic plant (MAP) traditionally cultivated and used in Alentejo, Portugal. However, few publications are available about its ethnobotanical applications. Four independent ethnobotanical surveys were carried out: throughout the region (2002–2003), in three villages (2013), and in city markets (2007 and 2022). Coriander was the most common fresh cultivated MAP (75% of the total area) and also the most representative MAP fresh herb in city markets. The leaves, mostly, were used fresh or frozen or transformed in piso. Some of the recipes have agro-industrial potential, such as piso and aromatized olive oil. Coriander essential oils (EOs) were isolated by hydrodistillation from aerial parts with inflorescence emergence (APIs) and from fruits, and fatty acids (FA) by solvent extraction from the fruits. Gas chromatography and gas chromatography-mass spectrometry analysis showed EOs dominated by n-decanal (21–24%), 2-trans-decenal (12–18%) and n-nonane (10–17%) in APIs, and linalool dominance (73–78%) in the fruits. Petroselinic acid (32–55%) was the dominant fatty acid. A literature survey on conventional and nonconventional extraction techniques showed a constancy in the dominant compounds isolated, highlighted piso as a home-made green-extraction procedure, but also reflected the relevance of coriander as a MAP with diverse industrial potential uses.