CDK1 and neoplasm: Acacetin shows a strong G1 and/or G2/M blockade effect, reduces the levels of CDK2, 4, and 6 in tumor cells in a dose-dependent and time-dependent manner, increases the level of p21, reduces the levels of cdc25c, CDK1, and cyclin B 1 protein, and makes cells stagnate in the G1 and G2/M phases (Singh et al., 2005).