Cytotoxic melodinus-type alkaloids from the ethanol extract of Melodinus fusiformis

A chemical investigation of the ethanol extract of the aerial parts of Melodinus fusiformis led to the isolation of six new melodinus-type alkaloids, melofusines A-E (1-6), along with one known compound, melodinine B. Structural elucidation of all the compounds was performed by spectral methods such as 1D and 2D NMR, IR, UV and HRESIMS. The isolated compounds were tested in vitro for cytotoxic potential against six tumor cell lines (Hep-2, SCL-1, CAL-27, UMSCC-1, Detroit-562 and TCA-83). As a result, compound 1 exhibited significant cytotoxic activities against all tested tumor cell lines with IC₅₀ values <5μM.