Purvalanol B is primarily used as a potent inhibitor of cyclin-dependent kinases (CDKs), making it a valuable tool in cell cycle research. It is widely applied in studies related to cell proliferation, apoptosis, and cancer biology. By blocking CDK activity, Purvalanol B helps researchers investigate the regulation of key cellular processes such as DNA replication and transcription. It has also been used in experiments to induce cell cycle arrest, particularly in tumor cell lines, supporting its role in exploring potential anticancer strategies. Additionally, due to its ability to cross cell membranes effectively, it is favored in cellular assays requiring intracellular kinase inhibition.