<div><p>This study was designed to evaluate the isolated flavonoids (chrysin <b>1</b>, and umbelliferone <b>2</b>) from <i>Potentilla evestita</i> for cytotoxic, antitumour-promoting and inhibition of protein denaturation activities. The results showed marked cytotoxic effect of compounds <b>1</b> and <b>2</b> in brine shrimp cytotoxic assay at various concentrations with LD<sub>50</sub> of 34.5 and 31.8 mg/mL, respectively. In Epstein–Barr-virus early antigen activation assay, both compounds <b>1</b> and <b>2</b> illustrated significant antitumour-promoting effect with IC<sub>50</sub> values of 462 and 308 mol ratio/32 pmol TPA, respectively. The cytotoxic and antitumour-promoting effects of compounds were strongly supported by inhibition of protein denaturation activity with IC<sub>50</sub> of 119 and 112 μg/mL, respectively. In conclusion, both compounds possess strong cytotoxic, antitumour-promoting and inhibition of protein denaturation activities.</p></div
