RESUMO
Purpurin is a common component ofRubia cordifolia L. The study on its molecular target was useful for elucidating the therapeutic material basis and action mechanism ofR. cordifolia. HT-29 cells were used in the cell culture. The highly expressed G Protein-coupled Receptor-35 (GPR35) agonist was used as target. The label-free optical biosensor cellular assay was used to investigate the agonist activity ofpurpurin at an endogenous receptor. The results showed thatpurpurin can cause DMR response in HT-29 cells. And the DMR response curve type was consistent with zaprinast. Its EC50 was 6.142± 0.189μmol·L-1. In addition,purpurinhad desensitization effect on GPR35 agonist zaprinast in HT-29 cells. GPR35 agonist ML145 blocked the DMR ofpurpurin. It was concluded thatpurpurinwas the GPR35 agonist.