Objective: To screen effective substances from Polygonum orientale flower extract by UHPLC-Q-TOF-MS technology for H9c2 myocardial cells. Method: The active substances in P. orientale flower extract were combined with H9c2 myocardial cells under imitated physiological environments

then the unattached substances were washed off by phosphate buffer solution (PBS) with pH of 7.4.After that

the conjugated compounds were eluted by PBS with pH of 4.0.These compounds released from target sites were collected and handled through Oasis HLB solid phase extraction column to be condensed.The separation was performed on a Eclipse Plus C18 column

mass sepectrometric data were obtained in electrospray ionization (ESI) positive and negative modes.Meanwhile

the chemical components were identified by comparing the retention times with standard substance and secondary fragment ions. Result: Seventeen compounds from P. orientale flower extract were identified preliminarily

and eight compounds were identified as protocatechuic acid

cianidanol

kaempferol

kaempferol-3-O-β-D-glucoside

quercetin

quercetin-3-O-β-D-glucoside

kaempferol-3-O-α-L-rhamnoside

paprazine. Conclusion: Throngh analysis of the fracture fluid compounds from the H9c2 cells extraction combined with active cells

the bioactive constituents from P. orientale flower extract interacted with myocardial cells are screened

this research provides a scientific fundament for material basis of effectiveness of P. orientale flower.