New potential antitumor compounds from the plant Aristolochia manshuriensis as inhibitors of the CDK2 enzyme

Two novel substituted phenanthrene compounds, SCH 546909 (1), and another glycoside (2) were isolated from the methanolic extract of the Chinese plant Aristolochia manshuriensis. The structures of 1 and 2 were established by NMR. They were identified as inhibitors of the CDK2 enzyme. Compound 1 was found to be a potent inhibitor of the CDK2 enzyme with an IC50 of 140nM, whereas compound 2 was found to be less active with an IC50 of >10μM.