Cytotoxic monoterpenoid-type alkaloids from the aerial parts of Melodinus morsei

Three new monoterpenoid alkaloids, melomorines A–C (1–3), along with melohemsine B (4), were isolated from the 70% ethanol extract of the aerial parts of Melodinus morsei. Structural elucidation of all the compounds was performed on the basis of spectral data. All the compounds were tested in vitro for cytotoxic activities. As a result, alkaloids 1, 2, and 4 exhibited cytotoxicities against all the five tested tumor cell lines with IC50 value of less than 20 μM.