Chlorahololides C-F:: a new class of potent and selective potassium channel blockers from Chloranthus holostegius

Four unusually fused polycyclic sesquiterpenoid dimers, chlorahololides C - F (1 - 4), were isolated from the whole plant of Chloranthus holostegius. Their structures and absolute configurations were established by spectroscopic methods, including 2D NMR and CD spectra. Chlorahololides C - F (1 - 4) exerted potent and selective inhibition on the delayed rectifier (I-K) K+ current with the IC50 values of 3.6 +/- 10.1, 2.7 +/- 0.3, 27.5 +/- 5.1. and 57.5 +/- 6.1 mu M, respectively. (c) 2008 Elsevier Ltd. All rights reserved.