ABSTRACT
<p><b>OBJECTIVE</b>To identify the tyrosinase inhibitory constituent quickly from Potentilla bifurca.</p><p><b>METHOD</b>The active constituent was found through fraction collecting and tyrosinase inhibitory activity by bioassay-linked HPLC method.</p><p><b>RESULT</b>The methanol extracts and BuOH fraction of Potentilla bifurca showed strong tyrosinase inhibitory activities. From BuOH fraction of Potentilla bifurca, the tyrosinase inhibitory constituent was isolated and identified as flavonoid, quercetin-4'-O-beta-D-glucoside. It express stronger tyrosinase inhibition than the known tyrosinase inhibitor, kojic acid (IC50 = 0.28 mmol x L(-1)) with IC50 value of 0.001 9 mmol x L(-1).</p><p><b>CONCLUSION</b>Bioassay-linked HPLC fractionation method was provided for determination the active constituents quickly from herbal medicines.</p>