TABLE 2

Activity of epoxygenase inhibitors on select human and rat P450 isoforms

IC50 values were taken from Fig. 3 or literature cited. Potencies are classified according to the IC50 values as either high (bold type, <25 μM), intermediate (italic type, 26–99 μM), or low (regular type, >100 μM). Literature citations in support of the epoxygenase activity of each P450 isoform are shown as footnotes in the right column.

IsoformIC50aEpoxygenase?
MS-PPOHPPOH
μM or % inhibition
1A1 hN.A.N.A.Someb
1A2 hN.A.N.A.Minorc
1B1 hN.A.N.A.No
2A6 hN.A.N.A.No
2B1 r23% at 80 μM23 (13–40)Yesd,e,f
2B6 h∼300 (166–526)63 (39–103)Yesd,e
2C6 r99 (70–140)161 (137–189)Yesg
2C8 h15hN.T.Yese,f
2C9 h11 (6–21)23 (19–28)Yesd,e,f
2C11 r16 (11–25)73 (61–87)Yese,f
2C19 h23% at 80 μM∼300 (213–444)Yesd,e
2D6 hN.A.N.A.No
2E1 hN.A.N.A.Minorc
4A2 rN.T.22iYesi
4A3 rN.T.6.5iYesi
  • h, human; r, rat; N.A., not active (<20% inhibition at 80 μM, duplicate measurements); N.T., not tested.

  • a Values are fitted IC50 values with 95% confidence intervals in parenthesis or percentage inhibition at the specified concentration of inhibitor.

  • b See Choudhary et al. (2004).

  • c Epoxygenase products from these enzyme most often are identified as minor or variable in amounts (Rifkind et al., 1995; Capdevila and Falck, 2002; Choudhary et al., 2004; Fer et al., 2008; however, see also Lucas et al., 2010).

  • d See Imaoka et al. (2005).

  • e See Roman (2002).

  • f See Capdevila et al. (2000).

  • g See Iliff et al. (2010).

  • h See Brand-Schieber et al. (2000).

  • i See Nguyen et al. (1999).