Two new steroidal alkaloids from the aerial part of Fritillaria walujewii

Phytochemical investigation on the aerial part of Fritillaria walujewii Regel resulted in the isolation of two new steroidal alkaloids, named as walujewine F (1) and G (2), and five previously reported compounds 3-7. Structural elucidation of compounds 1-7 was achieved by employing various spectroscopic techniques. The cholinesterase inhibitory potential of all the compounds was systematically evaluated. Compound 1 exhibited moderate AChE inhibition with the IC₅₀ value of 70.37 μM, while compound 2 demonstrated obvious dual AChE and BChE inhibitory effects, with the IC₅₀ values of 91.69 μM and 67.12 μM, respectively, but lower than the positive control galantamine (IC₅₀ values of 2.80 μM for AChE and 21.85 μM for BChE).