Design, synthesis and bioactivities evaluation of novel oleanolic acid derivatives as potent PI3K inhibitors

Oleanolic acid has previously been shown to possess PI3K inhibitory activity, thus, the purpose of this work was to generate a series of derivatives that improve the potency. Twenty rationally designed oleanolic acid derivatives were synthesized and tested the cytotoxicity and PI3K inhibitory activity. The results suggested that attachment of additional structural elements such as association of thiazole group to A ring and insertion of phenylurea group was important for increasing activities. The most active derivative was compound II2, which exhibited PI3K inhibitory activity (IC50 = 58.42 nmol/l) and improved interaction with activity site of PI3K according with docking studies.