Anti-5-hydroxytryptamine3 effect of galanolactone, diterpenoid isolated from ginger.

Abstract

It has been reported that an acetone extract of ginger and its fractions have anti-5-HT (5-hydroxytryptamine; serotonin) effects. In the present study, guinea pig ileum, rat stomach fundus and rabbit aortic strips are used in order to determine the constituents of fraction 2 which are responsible for anti-5-HT effect and to examine their pharmacological properties. The analysis of fraction 2-3 indicated that galanolactone, a diterpenoid, is one of the active constituents. In guinea pig ileum, galanolactone inhibited contractile responses to 5-HT with a pIC50 value 4.93. pIC50 value of galanolactone against the response to 2-methyl-5-HT, a selective 5-HT3 agonist, in the presence of methysergide at 1 x 10(-5) M was 5.10. pIC50 values of ICS 205-930, a selective 5-HT3 antagonist, were 5.30 and 7.49, respectively. The concentration-response curve of 5-HT was shown as a biphasic curve and galanolactone caused a selective shift to the right of the second phase. In the same preparations, the pIC50 value of galanolactone and ICS 205-930 against the response to carbamylcholine (CCh) was 4.45 and 4.46. The inhibitory effect of galanolactone on the 5-HT response in the stomach fundus and aortic strips was less than that in the ileum. In addition, in the thoracic aorta precontracted with 50 mM K+, the relaxing effect of galanolactone was about 1/10 of that of papaverine. These results suggest that the anti-5-HT effect of galanolactone, a diterpenoid isolated from ginger, is related to antagonism of 5-HT3 receptors.

Ginger Reduces Hyperglycemia-Evoked Gastric Dysrhythmias in Healthy Humans: Possible Role of Endogenous Prostaglandins

“…In addition to inhibiting cyclooxygenase and lipoxygenase activity, ginger exhibits effects on 5-HT 3 -mediated functions (Huang et al, 1991;Shibata et al, 1999). In experimental motion sickness in healthy humans, ginger blunts the increase in plasma vasopressin levels in response to circular vection, indicating possible actions on the release of this transmitter (Lien et al, 2003).…”

Potential health benefits and scientific review of ginger

“…Ginger also contains amadaldehyde, paradole, gingerdiols, gingerdiacetates, gingerenones, 6-gingersulfonic acid, diterpense, gingerglycolipids A, B and C (Qian and Liu 1992;Huang et al, 1991;Pecoraro et al, 1998;Anonymous 1997;Frisch et al, 1995).…”

Bioactivity and potential therapeutic benefits of some medicinal plants from the Caatinga (semi-arid) vegetation of Northeast Brazil: a review of the literature

“…The authors suggest that a daily total of 1000 mg of ginger in a capsule preparation can be suggested by care providers as a means of decreasing pregnancy nausea and vomiting in women who tend to herbal medicines. In addition, in isolated guinea pig ileum, several compounds in ginger have been shown to have anti-serotonin (5-hydroxytryptamine) effects (Yamahara et al, 1989;Huang et al, 1991). These early studies suggest that, at least in part, the anti-emetic action of either ginger or some of its constituents may be mediated centrally via 5-HT3 receptors, as these constituents have small molecular weights and could easily cross the blood brain barrier.…”