Effects of curcumin and curcumin analogues on TRP channels

A series of 33 curcumin analogues was synthesized and tested on TRPA1, TRPM8, and TRPV1 channels. Twenty of them acted as good modulators of TRPA1 channels. None was able to significantly activate TRPM8 channels, while curcumin itself and six curcuminoids belonging to the 1,3-dicarbonyl and acyclic series behaved as 'true' antagonists with IC50 values < 5 mu M. Only few curcuminoids were able to modulate TRPV1 channels with EC50 and IC50 values ranging from 3.4 and 6.0 mu M.