Abstract
Suaeda (S.) asparagoides $M_{IQ}$, one of the halophyte groups, has been used as a folk remedy for digestive disturbances in Korea. However, its pharmacological activity on gastrointestinal motility has not been reported yet. In this study, the effects of this halophyte extracts with various solvent fractions (ethanol, hexane, chloroform, ethyl acetate, butanol, and water) on mice ileal spontaneous motility was examined. All solvent fractions at the concentration of $100{\mu}g/ml$ showed inhibitory actions on spontaneous motility of ileum with the potency order of water > 70% ethanol > hexane ${\gg}$ chloroform ${\geq}$ butanol ${\geq}$ ethyl acetate, respectively. In addition, the water fraction of extracts from S. asparagoides $M_{IQ}$ (WFSA) dose-dependently ($1-100{\mu}g/ml$) inhibited the amplitude of spontaneous phasic contraction and area under the contractile curve (AUC). The inhibitory effect of water fraction at the concentration of $10{\mu}g/ml$ was not affected by tetrodotoxin (TTX), $Na^+$ channel blocker ($1{\mu}M$), and $N^w$-nitro-L-arginine Methyl Ester (L-NAME), nitric oxide synthase inhibitor ($100{\mu}M$). However, cyclopiazonic acid (CPA, $10{\mu}M$), inhibitor of sarcoplasmic reticulum $Ca^{2+}$-ATPase, almost blocked the inhibitory effects of WFSA ($10{\mu}g/ml$) on the spontaneous phasic contraction of mouse ileum. But, CPA did not inhibit the lowering basal tone effects of WFSA. The result of this study showed that various extracts of S. asparagoides $M_{IQ}$ induce inhibitory effects on spontaneous contraction of mice ileal segments. More over, the polar solvent fractions were shown to be more potent than non-polar solvent fractions. The effects of S. asparagoides $M_{IQ}$ extracts are not mediated by nerve or nitric oxide. The inhibitory effects of WFSA at least partially mediated by sarcoplasmic reticulum $Ca^{2+}$-ATPase. However, further study is required to determine the exact pharmacological mechanisms of this halophyte on its gastrointestinal motility inhibitory effects.
