Studies have demonstrated that
berberine exhibits the
antineoplastic action in rat model. Rat glial
tumor cells also have been shown to have N-
acetyltransferase activity. In this study, we reported the effects of
berberine on
arylamine N-acetyltransferase (
NAT) activity, gene expression, and
DNA adduct formation in human
brain tumor cell lines (G95/VGH and GBM 8401). The activity of
NAT (N-acetylation of substrate) was measured and determined by high-performance liquid chromatography (HPLC) assaying for the amounts of acetylated
2-aminofluorene (AF) and nonacetylated AF. Human
brain tumor cells (G9T/VGH and GBM 8401) were used for examining
NAT activity and gene expression and AF-
DNA adduct formation.
NAT gene expression was determined by polymerase chain reaction (PCR) for the levels of
mRNA NAT in both examined cells lines. The amounts of AF-
DNA adducts were also determined and quantities by HPLC. The results demonstrated that
NAT activity, levels of
mRNA NAT1 and AF-
DNA adduct formation in both examined cell were inhibited and decreased by
berberine in a dose-dependent manner. The apparent values of Km and Vmax from
NAT of both examined cells were also determined with or without
berberine cotreatment. The data also indicated that
berberine decreased the apparent values of Km and Vmax. These effects also indicate that
berberine is a uncompetitive inhibitor.