## 4. Conclusions  
This study provides a comprehensive evaluation of the phenolic composition and the antioxidant capacity of different accessions of oregano and thyme grown in different locations in Portugal. By focusing on lesser-studied phenolic compounds, such as flavonoids and phenolic acids, this research highlights the complex phenolic profiles beyond the well-known monoterpenes thymol and carvacrol. The major phenolic compound present in both aromatic plants is rosmarinic acid, a common phenolic compound in aromatic plants from the Lamiaceae family and recognized for its inflammatory, antioxidant, antiviral, and antibacterial activities. However, no strong correlation was found between the individual phenolic compounds and the antioxidant capacity, suggesting a more complex and synergetic effect between the different compounds. The levels of individual phenolic compounds and antioxidant properties depend on many factors, such as edaphocimatic conditions (including water and heat stress), the harvest time, drying conditions, and methods of the preparation of extracts. While statistical differences were found between different accessions, the results show a consistent pool/profile of the different phenolics amounts of the accessions and, in the case of thyme, even between morphotypes. Portuguese types of oregano and thyme represent a strong and consistent source of natural antioxidants and bioactive compounds that can be exploited for further food, pharmaceutical, or cosmetic applications, as well as to be used by the food industry as natural food additives. However, it is important to note that, like many aromatic plants, they can cause adverse effects if used  
Figure 5: Heatmap of the Pearson correlation coefficient (r) matrix between antioxidant capacity and individual phenolic compounds in thyme extracts. The abbreviations used are as follows: TPC—Total Phenol Content, DPPH—antioxidant activity based on 2,2-diphenyl-1-picrylhydrazyl assay, FRAP—antioxidant activity based on ferric reducing antioxidant power assay. improperly. Oregonano and thyme may lead to gastrointestinal issues, allergic reactions, and interactions with certain medications, especially when used in high doses. These potential risks should be considered in their application and further studies are recommended to ensure their safe use. Conceptualization, C.S. ; Data curation, A.R.S.M., A.S. and V.R.L. ; Formal analysis, A.R.S.M., C.A., A.S. and V.R.L. ; Funding acquisition, C.S., C.A. and A.S.-S.; Investigation, A.R.S.M., A.S. and V.R.L. ; Methodology, A.R.S.M., A.S. and V.R.L. ; Project administration, C.S. ; Resources, A.R.S.M., A.S. and V.R.L. ; Software, A.R.S.M. and A.S.; Supervision, C.S., C.A. and A.S.-S.; Validation, C.A., A.S. and V.R.L. ; Visualization, A.S.-S.; Writing--original draft, A.R.S.M. and V.R.L. ; Writing--review and editing, C.S., A.S., C.A. and A.S.-S. All authors have read and agreed to the published version of the manuscript. The work developed within the project was financially supported by PDR2020-7.8.4-FEADER -784-042741 \"Conservacao e melloramento de plantas aromaticas e medicinais (PAM)\" and the Foundation for Science and Technology (FCT, Portugal) for financial support through national funds. ARSM would like to thank FCT for her fellowship (2023.04705.BDANA). The work was supported by UIDB/00211/2020 with funding from FCT/MCTES through national funds. Not applicable. Data Availability Statement: Data will be made available on request. The authors declare no conflicts of interest. Limits of quantification (at \(\upmu\)g/mL extract) for 53 phenolic compounds by UHPLC-ToF-MS.