Table 4

Inhibition of CYP3A activity by five isolated furanocoumarins

Combination of FuranocoumarinsConcentration in Reaction MixtureResidual Activity4-a
GF-I-5GF-I-2GF-I-4DHBGF-I-1
nM %
Separately at high level2097.6  ± 0.84-165
75070.5  ± 7.24-165
1469.3  ± 4.54-165
88063.3  ± 1.54-165
1561.4  ± 0.74-165
Four at high level207501488038.7  ± 0.84-160
20750141538.8  ± 0.84-160
207508801537.0  ± 1.74-160
20148801535.7  ± 2.74-150
750148801530.0  ± 0.5
Five at high level20750148801530.3  ± 1.5
Five at low level121802.520176.0  ± 5.44-165

Furanocoumarins are added in methanolic solution, and then dried before the addition of other components in the reaction mixture.

  • 4-a Residual activities of testosterone 6β-hydroxylation by human liver microsomes are shown as percentages. Data are shown as mean ± S.D. of at least three determinations.

  • 4-150P < .05,

  • 4-160P< .01, and

  • 4-165P < .001 as compared with “Five at high level”.