Monastrol is primarily used in biological and biochemical research as a selective inhibitor of the kinesin Eg5, a motor protein essential for the proper separation of chromosomes during cell division. By inhibiting Eg5, Monastrol induces mitotic arrest, making it a valuable tool for studying cell cycle dynamics, mitosis, and the mechanisms of spindle assembly. It is particularly useful in cancer research, as it helps to understand the role of Eg5 in tumor cell proliferation and to explore potential therapeutic strategies targeting mitotic processes. Additionally, Monastrol serves as a model compound for developing other Eg5 inhibitors with potential clinical applications in cancer treatment.