Herein, we isolated five natural alkaloids, iso-corydine (iso-CORY), corydine (CORY), sanguinarine (SAN), chelerythrine (CHE) and magnoflorine (MAG), from traditional medicinal herb Dicranostigma leptopodum (Maxim.) Fedde (whole herb) and elucidated their structures. Then we synthesised G5. NHAc-PBA as targeting dendrimer platform to encapsulate the alkaloids into G5. NHAc-PBA-alkaloid complexes, which demonstrated alkaloid-dependent positive zeta potential and hydrodynamic particle size. G5. NHAc-PBA-alkaloid complexes demonstrated obvious breast cancer MCF-7 cell targeting effect. Among the G5. NHAc-PBA-alkaloid complexes, G5.NHAc-PBA-CHE (IC50=13.66 μM) demonstrated the highest MCF-7 cell inhibition capability and G5.NHAc-PBA-MAG (IC50=24.63 μM) had equivalent inhibitory effects on cell proliferation that comparable to the level of free MAG (IC50=23.74 μM), which made them the potential breast cancer targeting formulation for chemotherapeutic application. This work successfully demonstrated a pharmaceutical research model of 'natural bioactive product isolation-drug formulation preparation-breast cancer cell targeting inhibition'.