K252c is an aglycone, indolocarbazole alkaloid which is a protein kinase inhibitor of the Staurosporine family. K252c is a cell-permeable inhibitor of PKC (protein kinase C) (IC50 = 2.45 μM) that displays approximately 10-fold selectivity over PKA (protein kinase A) (IC50 = 25.7 μM). K252c is cytotoxic for A549 and P388 cells (IC50 = 2-3 mM). K252c also inhibits LACTB (β-lactamase), malate dehydrogenase (MDH2, MDHC, MDH1B) and chymotrypsin (IC50 values are 8, 8 and 10 μM respectively). K252c displays antiviral activity against GCV-sensitive and -resistant strains of human cytomegalovirus (HCMV) (IC50 values range from 0.13-0.32 μM).