Encouraged by the anti-myocardial ischemic effect of Corydalis hendersonii ethanol extract, a chemical re-investigation of the whole plant of C. hendersonii was performed, which led to the isolation of four new spir-obenzylisoquinoline N-oxide alkaloids, hendersines C-F (1-4), along with seven known isoquinoline alkaloids (5-11). The structures of the new isolates including absolute configurations were elucidated by the analysis of spectroscopic data and comparison of the experimental and calculated electronic circular dichroism (ECD) data. Compound 1 inhibited the NO production in lipopolysaccharide (LPS)-induced RAW 264.7 cells with an IC50 value of 70.3 mu M, and increased the cell viabilities with 40.0 +/- 3.9% against the oxygen glucose deprivation injury in H9c2 cells at 40 mu M.