Induction of quinone reductase by a methanol extract of Scutellaria baicalensis and its flavonoids in murine Hepa 1c1c7 cells

The effect of extracts of scutellariae radix (Scutellaria baicalensis Georgi) and its flavonoids, baicalin, baicalein and wogonin, on induction of quinone reductase (QR) in the Hepa lclc7 murine hepatoma cell Line was examined. A significant and dose-dependent induction of QR activity was observed in the methanol extract of scutellariae radix and baicalin, HPCL analysis showed that baicalin was contained as a main component in the methanol extract of scutellariae radix, indicating that baicalin may be the major active principle of QR induction mediated by scutellariae radix extract. To elucidate the mechanism of baicalin-mediated induction of QR enzyme activity, the effect on QR mRNA levels in Hepa lclc7 cell cultures was investigated, Using reverse transcriptase-polymerase chain reaction techniques, time- and dose-dependent induction of QR mRNA levels by baicalin were demonstrated in Hepa lclc7 cells. On the basis of these results, the scutellariae radix extract or baicalin can be regarded as a readily available, promising, novel cancer chemopreventive agent. (C) 1998 Lippincott Williams & Wilkins.