Three new isoquinoline alkaloids, including two aporphines (1 and 2) and one oxoaporphine (3), were isolated from the 90% EtOH extract of the whole plants of Thalictrum tenue Franch. The structures of the isolated compounds were established based on 1D and 2D (1H-1H COSY, HMQC, and HMBC) NMR spectroscopy, in addition to high resolution mass spectrometry, respectively. The isolated alkaloids were tested in vitro for cytotoxic activity against six esophageal carcinoma cell lines. Consequently, alkaloids 1-3 exhibited some cytotoxic activities against all the tested tumor cell lines with IC50 values less than 20 μM. [Formula: see text].
Keywords: Ranunculaceae; Thalictrum tenue; alkaloids; cytotoxicity.