Structural Identification of a New Tri-p-coumaroylspermidine with Serotonin Transporter Inhibition from Safflower

We previously reported that safflower (Carthamus tinctorius L.) ethyl acetate extract (HE) possessed an inhibitory action on serotonin (5HT) uptake in Chinese hamster ovary (CHO) cells expressing 5HT transporter (SERT) (S6 cells). Here, HE was adopted to go through an activity-guided isolation, and then an ingredient with potent SERT inhibitory action was obtained, which was elucidated as N-1,N-5-(Z)-N-10-(E)-tri-p-coumaroylspermidine (CX), a new coumaroylspermidine analog, by using spectroscopic methods including extensive 1D- and 2D-NMR analyses. Preliminary pharmacological study demonstrated that CX was a potent SERT inhibitor.