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Journal of Biomedicine and Biotechnology
Volume 2011 (2011), Article ID 389056, 7 pages
Review Article

On Benzofuroindole Analogues as Smooth Muscle Relaxants

Uimyung Research Institute for Neuroscience and Department of Pharmacology, Sahmyook University, 26-21 Kongkreung-dong, Nowon-gu, 139-742 Seoul, Republic of Korea

Received 3 May 2011; Accepted 14 July 2011

Academic Editor: J.-P. Jin

Copyright © 2011 Ike dela Peña and Jae Hoon Cheong. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.


At least two laboratories have independently reported the synthesis of benzofuroindole compounds having potential therapeutic implications in many disease states including those that involve smooth muscle hyperactivity. Through a series of in vitro screenings, they demonstrated the efficacy (and selectivity) of these compounds to potentiate large conductance calcium- (Ca2+-) activated K+ (BKCa) channels, by far, the most characterized of all Ca2+-dependent K+ channels. Interestingly, promising benzofuroindole derivatives such as compound 7 (10H-benzo[4,5]furo[3,2-b]indole) and compound 22 (4-chloro-7-trifluoromethyl-10H-benzo[4,5]furo[3,2-b]indole-1-carboxylic acid) both exhibited high bladder (versus aorta) selectivity, making them attractive alternative treatments for bladder overactivity. In recent reports, compound 22 (LDD175 or TBIC) also showed inhibition of ileum and uterine contractions, indicating multiple target tissues, which is not surprising as BKCa channels are ubiquitously expressed in the animal and human tissues. In this paper, the authors discuss the value of benzofuroindole compounds and the challenges that need to be overcome if they were considered as smooth muscle relaxants.