To complement the results obtained for the cell viability assay, Roy (1), which had the highest antiproliferative/cytotoxic effect against GB cells, was conjugated with a fluorescent probe to assess its biodistribution in the cells. Using fluorescence and confocal microscopy and acquired **data** and image analysis, we observed a pronounced fluorescence in the cells treated with both concentrations of Roy-BODIPY (12), 6.25 μg/mL (Figure 5B,D) and 25 μg/mL ( Figure 5A,C). Moreover, Roy-BODIPY (12) accumulated in the cytoplasm of cells instead of the nucleus (pointed out with N in each image) ( Figure 5). Using confocal microscopy, a distinctive accumulation in cytoplasmic vesicles was visible (marked with an arrow) ( Figure 5C,D). Therefore, the increased uptake of Roy (1) in cytoplasmic vesicles supported the finding of the higher antiproliferative/cytotoxic activity of this phytochemical ( Figure 5). Furthermore, a possible explanation for these results could be the fact that this compound may target the mitochondria and induce the mitochondriadependent intrinsic pathway of apoptosis. Further studies should be performed to unveil the exact mechanism of action of Roy (1).   (Lisbon, Portugal). The plant name was checked at http://www.worldfloraonline.org/ (World Flora Online, accessed 12 January 2022). After collecting, the plant was air dried (25 • C) under the shade and stored in cardboard boxes protected from light and humidity to maintain its stability. Leaves and stems were separated at the beginning of this study. Experimental results from the leaves were previously published [45].