Effects of (-)-menthol on arylamine N-acetyltransferase activity in human liver tumor cells.
To evaluate whether or not (-)-menthol affects arylamine N-acetyltransferase (NAT) activity, we selected human liver tumor cell line (J 5) for examination. By using high performance liquid chromatography, NAT activity for acetylation of 2-aminofluorene (AF) was determined. (-)-Menthol displayed a dose-dependent inhibition to cytosolic NAT activity. Time-course experiments showed that NAT activity measured from intact human liver tumor cells was inhibited by (-)-menthol for up to 24 hrs. But in human liver tumor intact cells, the low doses (0.0032 and 0.032 mM) of (-)-menthol promoted the NAT activity and the high doses (3.2 and 32 mM) of (-)-menthol inhibited NAT activity and the 0.32 mM (-)-menthol did not show any significant differences between control and (-)-menthol treated groups. Using standard steady-state kinetic analysis, it was demonstrated that (-)-menthol was a possible uncompetitive inhibitor (decrease Km and Vmax) to NAT activity in cytosols. This report is the first demonstration which showed (-)-menthol affect on human liver tumor cells NAT activity.
Lin
J P
JP
School of Chinese Medicine, China Medical College, Taichung, Taiwan.
Li
Y C
YC
Lin
W C
WC
Hsieh
C L
CL
Chung
J G
JG
D000970:Antineoplastic Agents / Q000494:pharmacology*; D001191:Arylamine N-Acetyltransferase / Q000378:metabolism*; D003600:Cytosol / Q000201:enzymology; D004305:Dose-Response Relationship, Drug; D006801:Humans; D007700:Kinetics; D008113:Liver Neoplasms / Q000188:drug therapy* / Q000201:enzymology*; D008610:Menthol / Q000494:pharmacology*; D013997:Time Factors; D014407:Tumor Cells, Cultured
D000970:Antineoplastic Agents; D008610:Menthol; D001191:Arylamine N-Acetyltransferase