MSC2504877 is an inhibitor of tankyrase and enhances the effects of clinical CDK4/6 inhibitors. MSC2504877 suppresses the upregulation of Cyclin D2 and Cyclin E2 caused by palbociclib and enhances the suppression of phospho-Rb.

Osthol hydrate is a natural product.

D-proline is an isomer of the naturally occurring amino acid L-Proline. D-amino acids have been found in relatively high abundance in human plasma and saliva. These amino acids may be of bacterial origin but there is also evidence that they are endogenously produced through amino acid racemase activity.