- Iron tetrakis (n-methyl-4'-pyridyl) porphyrinato (FeTMPyP) is a potent scavenging antioxidant and an inhibitor of stimulant-induced NF-kappaB activation of raw 264.7 macrophages. Kang, J.L., Lee, H.S., Pack, I.S., Leonard, S., Castranova, V. J. Toxicol. Environ. Health Part A (2001)