**5. Conclusions**

In conclusion, we found that rohitukine not only perturbs physiological mechanisms in mammalian and yeast cells but also affects the growth parameters of *A. thaliana* by triggering ROS generation and metabolic changes and interfering with photosynthetic machinery. The inhibition of PSII activity combined with the upregulation of antioxidant system genes is most likely the basis of its property as an allelochemical. The activity of rohitukine inside *A. thaliana* tissues represents an example of a mechanism whereby active medicinal compounds exert their influence on multiple targets instead of single sites of action. The relative importance and the effectiveness of rohitukine perturbation inside the model plant *A. thaliana* give us an idea of how similarly plant and animal cells respond to the medicinally important molecule rohitukine. Moreover, the phytotoxic potential of rohitukine may help in maintaining the ecological interactions of the parent plant.

**Author Contributions:** Methodology, formal analysis, writing—original draft preparation, S.A.; writing—review and editing, data curation, M.A.; HPLC, GC–MS, LC–MS, A.K.; supervision, conceptualization, resources, writing—review and editing, funding acquisition, S.G.G. All authors have read and agreed to the published version of the manuscript.

**Funding:** Support for this study was provided by the Council of Scientific and Industrial Research, India (MLP110006 and HCP38).

**Institutional Review Board Statement:** Not applicable.

**Informed Consent Statement:** Not applicable.

**Data Availability Statement:** Data are contained within the article.

**Acknowledgments:** S.A. is thankful to the Council of Scientific and Industrial Research, India, for Senior Research Fellowships. The authors also thank Utpal Nandi for his valuable advice during the editing of the manuscript.

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