PF 3644022 is potent, ATP-competitive inhibitor of mitogen-activated protein kinase (MAPK)-activated protein kinase-2 (MK2) (IC50 = 5.2 nM; Ki = 3 nM). Inhibits tumor necrosis factor α (TNFα) production in U937 monocytic cells and peripheral blood mononuclear cells (PBMCs) (IC50 = 160 nM). PF-3644022 is orally efficacious at inhibiting TNFalpha production in LPS-challenged rats and blocking paw swelling in the chronic SCW-arthritis model.

Rottlerin is a principal phenolic compound of the Kamala plant Mallotus philippinensis. It was thought to be a selective inhibitor of PKCδ (protein kinase Cδ) (IC50=3-6 uM). It also inhibits PKCα, PKCβ, PKCγ, PKCε, PKCη, PKCζ and eEF2K (CaMK III) (IC50 = 5.3 uM). In HT1080 human fibrosarcoma cells, rottlerin induces apoptosis and autophagy via a PKCδ-independent pathway. When tested on HERG channels, rottlerin increased both step and tail HERG current by leftward shifting the voltage and dependence of HERG activation and slowing channel deactivation. Rottlerin is an inhibitor of Chk2, MAPKAPK-2, Pim-3, PKCλ, PKCθ, Plk, PRAK, SRPK1 and an activator of AMPK and HERG. There have been a number of studies published with evidence against the role of Rotterlin as a specific PKCδ inhibitor.