AbstractIntroductionMacleaya cordata (Willd) R. Br. (Papaveraceae family) is a well‐known traditional Chinese medicine used to treat muscle pain, inflamed wounds, and bee bites. Benzo[c]phenanthridine alkaloids are the main active ingredients in M. cordata. In this work, sanguinarine and chelerythrine were efficiently extracted and purified by ultrahigh‐pressure extraction (UHPE) technique and pH‐zone‐refining counter‐current chromatography (PZRCCC) from M. cordata.ObjectiveTo develop an efficient UHPE method followed by an efficient separation technique using PZRCCC for benzo[c]phenanthridine alkaloids from the study plant species, and to evaluate the study samples for anti‐breast cancer activity.MethodologyThe optimal extraction conditions were optimised as extraction pressure 200 MPa, extraction solvent 95% ethanol, solid–liquid ratio 1:30 (g/mL) and extraction time 2 min. A two‐phase n‐hexane/ethyl acetate/i‐propanol/water (1:3:1.5:4.5, v/v) solvent system was optimised with 10 mmol triethylamine in the upper phase and 10 mmol trifluoroacetic acid in lower phase in PZRCCC. The sample loading was optimised as 2.50 g. Moreover, the samples were evaluated for anti‐breast cancer activity later on.ResultsThe 2.50 g sample loading yielded 0.45 g of sanguinarine and 0.59 g chelerythrine in one‐step separation using PZRCCC. The anti‐breast cancer activities of sanguinarine and chelerythrine were found stronger than positive control (vincristine 5.04 μg/mL) with half‐maximal inhibitory concentration values of 0.96 and 3.00 μg/mL, respectively.ConclusionThis study showed that the established methods were efficient in extraction (UHPE) and separation (PZRCCC) of the sanguinarine and chelerythrine from M. cordata.