## 4 Conclusions  
The aroma profiles, phenolic compounds, and antibacterial and antioxidant effects of Egyptian dukkah and Syrian za'atar were evaluated in this study. Attempts to characterize essential oil compositions of the herbal blends revealed the abundance of ethers and monoterepne hydrocarbons in dukkah and za'atar, respectively. Alcohols, aldehydes, aromatics, carboxylic acids, esters, furans, ketones, nitrogen-containing compounds, oxides, phenols, pyrans, pyrroles, and sesquiterpene hydrocarbons were also detected. HPLC further revealed that both dukkah and za'atar were rich in phenolics, with rosmarinic and ferulic acids as the most abundant, especially in the thyme-based Egyptian dukkah (EDT). Regarding the vapor-phase of the four herbal blends, blends showed variable antibacterial activity, with nut-based Egyptian dukkah (EDN) recording the highest antibacterial activity against the tested pathogens, and sumac-based Syrian za'atar (SZS) recording the lowest antibacterial activity. The in vitro assays affirmed the antioxidant potential of the four herbal blends. Thyme-based za'atar (SZT) showed the highest DPPH and ABTS scavenging activities as well as the highest ferric ion reducing potential, while thyme-based Egyptian dukkah (EDT) showed the highest ORAC capacity followed by the highest chelation capacity. The presence of thyme may explain za'atar's enhanced free radical scavenging antioxidant activities, while the presence of nuts may explain the chelation activity as well as the potentiation of dukkah's antimicrobial activities. Further studies are needed to provide the complete chemical characterization of Egyptian dukkah and Syrian za'atar, as well as to demonstrate the beneficial effects of the two herbal blends as typical examples for plant-based diets. Further research is also required to investigate the herbal blends for other potential biological activities and to examine how much a synergized effect is observed compared to herbal blends of individual components regarding other effects as revealed from antimicrobial assays. **Author Contributions:** [PERSON] and [PERSON] conceptualized the study; [PERSON] and [PERSON] prepared the headspace volatiles using SPME and performed the GC/MS analysis; [PERSON] identified the metabolites; [PERSON] revised the metabolites identification; [PERSON] prepared the samples and performed the HPLC analysis; [PERSON] tested the antimicrobial activity and wrote her part; [PERSON] prepared the extracts for the antioxidant assays; [PERSON] and [PERSON] managed the resources and prepared the EDN; [PERSON] and [PERSON] wrote the first and the final drafts; [PERSON], supervised the work and revised the final manuscript; [PERSON] and [PERSON] funded the work and were responsible for co-writing and revision of the manuscript. All authors have read and agreed to the published version of the manuscript. **Funding:** This project received funding from Deanship of Scientific Research at Umm Al-Qua University, Saudi Arabia, for supporting this work by grant code (22 UQU4290565 DSR89), and Taif University Researchers Supporting Project number (TURSP-2020/56), Taif University, Taif, Saudi Arabia. **Institutional Review Board Statement:** Not applicable. **Informed Consent Statement:** Not applicable. **Data Availability Statement:** Not applicable. **Acknowledgments:** The authors would like to extend their sincere appreciation to Taif University Researchers Supporting Project number (TURSP-2020/56), Taif University, Taif, Saudi Arabia. Additionally, the authors would like to thank the Deanship of Scientific Research at Umm Al-Qua University for supporting this work by grant code (22 UQU4290565 DSR89). [PERSON] would like to thank the [PERSON] foundation, Germany, for financial support. Authors are grateful to [PERSON] for assistance in running GCMS analysis at Global institute of health, American University in Cairo, Egypt. **Conflicts of Interest:** The authors declare no conflict of interest. **Sample Availability:** Samples of the compounds are available from the authors.