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- Ecotoxicity of plant extractsPublication . Ferraz, Celso Afonso Pestana; Pastorinho, Manuel Ramiro Dias; Sousa, Ana Catarina; Oliveira, Ana Cristina Palmeira deSince ancient times, plants have been used by mankind as an important source of bioactive compounds with different uses ranging from traditional medicine, food, perfumery, and cosmetics. Currently, its use spreads to almost all economic sectors and new applications keep emerging. One of the great applications of compounds that can be extracted from plants is obtained in the form of essential oil. Plants that produce essential oils do it naturally and this production is linked to many factors such as response to stress, as a defence against pathogen attacks and even as a way to attract pollinators that play an important role in the reproduction of the plant, being also linked to the environmental and ecological conditions of the area in which the plant grows. These essential oils are obtainable industrially from the plants that produced them by a distillation process or in certain cases by a mechanical process. During the distillation process to obtain essential oils, another economically interesting product can be attained: hydrolates, which are generally composed of more hydrosoluble molecules that remain in the distillation water. Another product that can be obtained from plants are extracts, which are extracted by treating parts of a plant with a solvent. Global essential oil production has been continuously increasing over the last decade and it is expected to continue rising over the next years. This growing production can be linked to the ever-bigger demand by consumers for natural products. From an academic point of view, it can also be said that research for new compounds and new applications of products extracted from plants has been increasing. In this way, the “InovEP Project – Innovation with Plant Extracts” has the goal to connect the university and the industry, providing scientific knowledge that can be used by companies linked to the production of essential oils and other plant extracts, as well as companies that want to use these products to develop new applications based in scientific evidence. Among the studies performed, one of the goals is to study the environmental safety of these products. The work described in this dissertation focused on the ecotoxicological evaluation of essential oils, hydrolates and extracts obtained from several plants studied in the project: Cistus ladanifer; Cupressus lusitanica, Echinacea purpurea, Eucalyptus globulus, Hamamelis virginiana, Helichrysum italicum, Humulus lupulus, Matricaria chamomilla, Ocimum basilicum, Thymbra capitata, Thymus citriodorus and Syzygium aromaticum. The tests performed focused on the acute toxicity towards aquatic organisms using the cladoceran Daphnia magna as model organism. Commonly called “water-flea”, D. magna is one of the recommended organisms to perform toxicity tests in aquatic systems by several international organizations such as the European Union (EU), Organization for Co-operation and Economic Development (OECD), the American Society for Testing and Materials (ASTM), and the International Organization for Standardization (ISO). The results, in general, show that essential oils can cause effects at lower concentrations when compared to the studied extracts and hydrolates. The S. aromaticum essential oil caused effects at lower concentrations, followed by the T. capitata essential oil, E. globulus essential oil and C. ladanifer essential oil. Of all the essential oils, only the one from H. italicum did not cause effects up to the highest concentration tested. Of all the H. lupulus extracts tested, immobilisation of the test organisms was only observed with high concentrations of the chloroform extract, obtained from the flowers. All the other extracts did not cause immobilisation up to the highest concentrations tested, and the same trend was observed with all the hydrolates tested. In terms of classification of the acute toxicity of essential oils, extracts and hydrolates, the GHS (Globally Harmonized System for Classification and Labelling of Chemicals) proposed by the United Nations was followed, which is also used in the European Union. Thus, the S. aromaticum essential oil can be classified as toxic to aquatic systems under the “Acute 2” category, and the T. capitata and E. globulus essential oils under the “Acute 3” category. The essential oils from C. ladanifer, H. italicum and all the extracts and hydrolates tested can not be classified, being considered not toxic, as the obtained results are above the classification limits proposed in the GHS. The S. aromaticum, T. capitata and E. globulus essential oils can cause acute adverse effects in aquatic systems, particularly in organisms in the same trophic level as D. magna, and so, precautions should be taken to avoid accidental or intentional contaminations of aquatic systems. For the other essential oils, extracts and hydrolates, the same precautions should be taken since, although they can not be classified as toxic, the effects that they can cause in organisms from different trophic levels remain unknown.