**4. Conclusions**

*Aerva javanica* is a xerophytic EO-bearing plant. The seasonal variation showed a significant effect on the flowers' EO yield, in which the best season to extract the highest EO yield is spring (0.011%). Similarly, the seasonal variation has a significant effect on the antioxidant activity of *A. javanica* flowers' EO, showing the best activity during the spring, tested in vitro using antioxidant assays (DPPH, FRAP, and ABTS).

The chemical composition of the flowers' EO extracted in the optimal season (during spring) is characterized with 29 identified volatiles, of which the major volatiles are angustione (20.72%) and evodone (14.77%).

*A. javanica* flowers' EO is a good resource of natural antioxidants, and has a high potential for the pharmaceuticals industry. Future clinical antioxidant studies for fractionate EO compounds are highly recommended.

**Author Contributions:** Conceptualization and methodology, S.M.S.; validation, A.J. and M.A.M.A.; writing—original draft preparation, S.M.S.; writing—review and editing, S.M.S., M.A.M.A. and A.J.; supervision, M.A.M.A. and A.J.; funding acquisition, M.A.M.A. All authors have read and agreed to the published version of the manuscript.

**Funding:** This research was funded by UAEU fund No. 31F029.

**Acknowledgments:** We express our appreciation to Ali El-Keblawy (University of Sharjah) and Shyam Kurup for the valuable knowledge related to the UAE native plants. Senthilkumar Annadurai (Research Associate, CAVM, UAEU) for his great support in the GC-MS analysis. Ali Al Marzouqi (Dean, College of Graduate Studies, UAEU) for sharing his valuable knowledge related to EO. Saeed Tariq (College of Medicine and Health Sciences, UAEU) for his assistance on SEM. Sajid Maqsood, Hina Kamal, and Babucarr Jobe (late) (Department of Nutrition, CAVM, UAEU), for the valuable assistance in conducting the antioxidant tests. Arshed el Daley (Agriculture Engineer, Al Foah Experimental Farm, CAVM), Abou-Messallam Azab (Lab Specialist, Horticulture Lab, CAVM), Saad Ismail (Lab Specialist, Soil and Water Lab, CAVM) and Rahaf Ajaj (Abu Dhabi University) for their cooperation and continuous support. This research was supported by the United Arab Emirates University (UAEU), College of Food and Agriculture, fund No. 31F029.

**Conflicts of Interest:** The authors declare no conflict of interest.
