Research articles
ScienceAsia 51 (2023): 1-11 |doi:
10.2306/scienceasia1513-1874.2023.090
Effect of condensed tannins from black currant (Ribes nigrum)
on acetylcholine-induced contractility in isolated rat intestine
Chaweewan Klongsiriweta,b, Watcharapong Purintrapibala, Paphon Paphochananga,
Aunchalee Prammanoc, Nawiya Huipaod, Siriphun Hiranyachattadaa,*
ABSTRACT: The condensed tannins (CTs) from black currant (R. nigrum) leaves were isolated as a tannin fraction
to investigate their effect on isolated rat duodenal contraction induced by acetylcholine (ACh). The mechanisms of
CT action were compared with those of a muscarinic receptor antagonist (atropine) and a calcium channel blocker
(verapamil). Duodenal segments were fixed in organ bath, and the frequency, amplitude, and tone of contraction
were recorded. The experiments were performed in seven groups, including the vehicle control, CTs (10, 50, 100,
and 300 ?g/ml), atropine (1.55?10?5 M), and verapamil (10?6 M), with cumulative additions of ACh (10?8?10?4 M).
The possibility that CTs might act by altering ion channel activity in intestinal epithelial cells was tested in a human
colonic adenocarcinoma cell line by measuring the equivalent short-circuit current, compared with that induced by an
adenylyl cyclase activator forskolin (10 ?M). It was found that CTsatlowconcentrations(10and50?g/ml)significantly
decreased the frequency of ACh-induced duodenal contractions. Only the CTs at high concentration (300 ?g/ml)
were able to inhibit ACh-induced amplitude and tone of contraction, similar to those of atropine, but not verapamil.
Preliminary data of equivalent short-circuit currents were unaltered after the four doses of CTs, in contrast to forskolin.
It is concluded that the mechanism of CT action is more likely mediated via the muscarinic receptor signaling pathway
rather than through inhibition of Ca2+ channels in intestinal pacemaker and smooth musclecell membranesorepithelial
cAMP-dependent Cl? secretion.
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| a |
School of Pharmacy, Walailak University, Nakhon Si Thammarat 80160 Thailand |
| b |
One Health Research Center, Walailak University, Nakhon Si Thammarat 80160 Thailand |
| c |
The Center for Scientific and Technological Equipment, Walailak University, Nakhon Si Thammarat 80160 Thailand |
| d |
Department of Physiology, Division of Health and Applied Sciences, Faculty of Science, Prince of Songkla University,
Songkhla 90110 Thailand |
* Corresponding author, E-mail: siriphun.hi@wu.ac.th
Received 10 Mar 2024, Accepted 0 0000
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