Effect of single-walled carbon nanotubes on cytochrome P450 activity in human liver microsomes in vitro.
Single-walled carbon nanotubes (SWCNTs) are made from a rolled single sheet of graphene with a diameter in the nanometer range. SWCNTs are potential carriers for drug delivery systems because antibodies or drugs can be loaded on their surface; however, their effect on the activities of cytochrome P450 (CYP) remains unclear. The aim of this study was to investigate the effect of two kinds of SWCNTs with different lengths (FH-P- and SO-SWCNTs) on human CYP activity. In addition, other nano-sized carbon materials, such as carbon black, fullerene-C60 , and fullerene-C70 were also evaluated to compare their effects on CYP activities. Ten CYP substrates (phenacetin, coumarin, bupropion, paclitaxel, tolbutamide, S-mephenytoin, dextromethorphan, chlorzoxazone, midazolam, and testosterone) were used. Testosterone 6β-hydroxylation and midazolam 1'-hydroxylation, which are catalysed by both CYP3A4 and CYP3A5 in liver microsomes, were decreased by 25% and 45%, respectively, in the presence of 0.1 mg/ml SO-SWCNT. Dextromethorphan O-demethylation, which is catalysed mainly by CYP2D6, was decreased by 40% in the presence of SO-SWCNT. Other CYP activities, however, were not attenuated by SO-SWCNT. FH-P-SWCNT, carbon black, fullerene-C60 , and fullerene-C70 at 0.1 mg/ml had no effect on CYP activities. The Ki values for testosterone 6β-hydroxylation, midazolam 1'-hydroxylation, and dextromethorphan O-demethylation in liver microsomes were 136, 34, and 56 μg/ml, respectively. SO-SWCNT was determined to be a competitive inhibitor of CYP3A4, CYP3A5, and CYP2D6. These results suggest that the effect of SO-SWCNT differs among CYP isoforms, and that the inhibition potency depends on the physicochemical properties of the nanocarbons.
['Asai|Yuki|Y|', 'Sakakibara|Yukiko|Y|', 'Inoue|Rina|R|', 'Inoue|Rikako|R|', 'Nadai|Masayuki|M|', 'Katoh|Miki|M|http://orcid.org/0000-0003-0825-6097']
D065607:Cytochrome P-450 Enzyme Inhibitors D003577:Cytochrome P-450 Enzyme System D006801:Humans D007527:Isoenzymes D008862:Microsomes, Liver D037742:Nanotubes, Carbon D053260:Soot
single-walled carbon nanotubes cytochrome P450 human liver microsomes inhibition