ObjectiveTo compare the effects of total alkaloids， matrine， and sophoridine extracted from Sophora alopecuroides on the activity of pheochromocytoma cells （PC12 cells）. MethodThe effect of S. alopecuroides total alkaloids， matrine， and sophoridine at concentrations of 2， 1， 0.5， 0.25， 0.125， and 0.062 5 g·L^-1 on the proliferation of PC12 cells was evaluated using the 3-（4，5-dimethylthiazol-2-yl）-2，5-diphenyl tetrazolium bromide （MTT） assay. The lactate dehydrogenase （LDH） leakage rate was measured by enzyme-linked immunosorbent assay （ELISA）. Flow cytometry was used to assess cell apoptosis rate， cell cycle distribution， and intracellular Ca²⁺ levels. Real-time quantitative polymerase chain reaction （Real-time PCR） was performed to determine the mRNA transcription levels of B-cell lymphoma-2 （Bcl-2） and Bcl-2-associated X protein （Bax）. Protein expression levels of apoptosis-related proteins Caspase-3， Caspase-8， Bcl-2， and Bax were detected by Western blot. ResultCompared to the control group， S. alopecuroides total alkaloids， matrine， and sophoridine inhibited the proliferation of PC12 cells， increased LDH leakage rate， enhanced intracellular Ca²⁺ fluorescence intensity， and induced cell apoptosis in concentration-dependent manner （P<0.05， P<0.01）. Among them， S. alopecuroides total alkaloids had the strongest inhibitory effect on cell proliferation and induction of apoptosis in PC12 cells （P<0.01）. After treatment with S. alopecuroides total alkaloids， matrine， and sophoridine， the cell cycle progression of PC12 cells was arrested at G₁/G₀ in the S. alopecuroides total alkaloids group， and at G₁/S in the matrine and sophoridine groups. The expression levels of Bax mRNA were significantly increased （P<0.05， P<0.01）， while the expression levels of Bcl-2 mRNA were significantly decreased （P<0.05， P<0.01）. All treatments significantly downregulated the expression of the anti-apoptotic protein Bcl-2 （P<0.05， P<0.01） and upregulated the expression of the pro-apoptotic proteins Bax， Caspase-3， and Caspase-8 （P<0.05， P<0.01）， with the most significant protein expression changes observed in the S. alopecuroides total alkaloids group. ConclusionAmong the S. alopecuroides total alkaloids， matrine， and sophoridine， S. alopecuroides total alkaloids exhibit the strongest inhibitory effect on the activity of PC12 cells， and its mechanism of action may be related to the inhibition of anti-apoptotic protein expression， upregulation of pro-apoptotic protein expression， and activation of the mitochondrial Caspase-8 apoptotic pathway.