An aqueous extract of Poncirus fructus activates the prokinetic activity of 5-HT receptor subtype 4 without hERG interaction

Won Sik Shim, Heejung Back, Sang Won Jung, Jun Woo Kim, Yongwoo Jang, Byeongjun Lee, Eun Kyoung Seo, Uhtaek Oh, Chang Koo Shim

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12 Scopus citations


Aim of the study: Poncirus fructus (PF) - also known as the dried, immature fruit of Poncirus trifoliata (L.) Raf. (Rutaceae) - is a natural substance that has long been used for various gastrointestinal disorders in eastern Asia. An aqueous extract of PF (PF-W) has particularly potent gastroprokinetic effects, but its molecular mechanism was not well understood. Identification of the underlying prokinetic mechanism of PF-W was pursued in the present study. Materials and methods: Changes in in vitro cAMP levels and in vivo intestinal transit rate (ITR) caused by PF-W were measured after pretreatment with GR125487, an antagonist for serotonin receptor subtype 4 (5-HT4R). An [3H] astemizole binding assay and electrophysiology experiments were performed to determine if PF-W has any interaction with the human ether-à-go-go related gene (hERG) potassium channel. Results: PF-W induced an increase in intracellular cAMP in 5-HT4R-expressing HEK293T cells, indicating that PF-W does activate 5-HT4R. Moreover, pretreatment with GR125487 successfully blocked the increase, suggesting that the response was 5-HT4R-specific. More importantly, pretreatment of GR125487 in rats inhibited the elevation of ITR by PF-W, indicating that the prokinetic effect of PF-W was indeed exerted via 5-HT4R. On the other hand, both [3H]-astemizole binding assay and electrophysiological experiments revealed that PF-W did not interfere at all with the hERG channel. Conclusion: It was found that PF-W exerts its prokinetic activity through a 5-HT4R-mediated pathway, with no interaction with hERG channels. Therefore, PF-W is a good candidate that might be developed as a prokinetic agent with fewer expected cardiac side effects.

Original languageEnglish
Pages (from-to)328-333
Number of pages6
JournalJournal of Ethnopharmacology
Issue number1
StatePublished - 28 Oct 2010


  • 5-HT4
  • HERG
  • Intestine
  • Motility
  • Poncirus fructus
  • Prokinetic


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