High affinity JNK inhibitor (Ki values are 25-50 nM). Inhibits JNK via competitive binding of the ATP-binding site of active, phosphorylated JNK. Exhibits > 40-fold selectivity for JNK over p38, ERK, IKK2, protein kinase C, Lck and ZAP70. Hepatoprotective. Also inhibits HCMV replication.