Abstract
Tagetes lucida has been used in traditional medicine as a remedy to alleviate several gastrointestinal disorders that provoke stomachaches, abdominal cramps, and diarrhea. However, there is not enough scientific evidence that supports these effects. Therefore, the purpose of this study was to evaluate antispasmodic and antidiarrheal activities of aqueous extract of T. lucida (AqExt-TL) as well as its mechanism of action in experimental models. Antispasmodic activity and the mechanism of action of AqExt-TL were assessed on segments of the guinea pig ileum precontracted with KCl, acetylcholine (ACh), or electrical field stimulation (EFS). Furthermore, the antispasmodic effect of two coumarins (umbelliferone and herniarin) previously identified in this species was evaluated. Antidiarrheal activity of AqExt-TL was determined using the charcoal meal test in mice. AqExt-TL showed antispasmodic activity in segments of the guinea pig ileum precontracted with KCl (83.7 ± 1.9%) and ACh (77.2 ± 5.3%) at the maximal concentration; however, practically, it did not alter the contractions induced by EFS (10.1 ± 2.2%). Antispasmodic activity of AqExt-TL was not significantly altered by hexamethonium (a ganglionic blocker) or L-NAME (an inhibitor of nitric oxide synthase). However, this extract decreased the maximal contractile response to calcium (82.7 ± 8.5%), serotonin (68.1 ± 8.5%), and histamine (63.9 ± 5.9%) in their concentration-response curves. Umbelliferone and herniarin also induced an antispasmodic effect on tissues precontracted with KCl. In addition, low doses of AqExt-TL reduced to 50% the distance traveled by charcoal meal in the gastrointestinal transit model in mice as loperamide, an antidiarrheal agent, did. These results provided evidence of the antispasmodic and antidiarrheal activity of T. lucida, which supports its use in the folk medicine in relieving symptoms in some gastrointestinal disorders. In the antispasmodic effect, the blockade of histaminergic and serotoninergic pathway as well as the calcium channels seems to be involved. Finally, umbelliferone and herniarin could be partially responsible for the antispasmodic activity induced by T. lucida.
Highlights
Functional gastrointestinal disorders such as dyspepsia or irritable bowel syndrome cause stomachaches, abdominal cramps, and diarrhea. ese symptoms have been traditionally treated with herbal medicines all over the world [1, 2]
In the experiments to explore the mechanism of action, the results showed that neither L-NAME nor hexamethonium significantly modified the antispasmodic effect induced by 300 μg/mL of AqExt-TL on tissues contracted with KCl (Figure 2(a))
Results showed that umbelliferone and herniarin induced an antispasmodic effect on the guinea pig ileum precontracted with KCl from 31.6 to 316.2 μg/mL with an Emax of 95.2 ± 3.0% and 55.7 ± 10.1% and an EC50 of 75.2 ± 1.1 and 160.1 ± 1.2 μg/mL, respectively (Figure 4). e Emax and EC50 values of both coumarins showed significant difference and, according to these, umbelliferone was more effective and potent than herniarin in inducing an antispasmodic effect
Summary
Functional gastrointestinal disorders such as dyspepsia or irritable bowel syndrome cause stomachaches, abdominal cramps, and diarrhea. ese symptoms have been traditionally treated with herbal medicines all over the world [1, 2]. Evidence-Based Complementary and Alternative Medicine “anicillo” or Mexican tarragon, is an endemic plant in Central America and Mexico that is prepared from fresh flowers or from aerial parts of the plant and orally consumed as infusion to alleviate stomachaches and diarrhea, mental agitation, or symptoms of a hangover, as well as infections caused by parasites [3]. The aqueous infusion is popularly consumed, there is no evidence on the effect of the aqueous extract of T. lucida on the gastrointestinal system, let alone on the mechanism of action involved. The purpose of this study was to evaluate the antispasmodic and antidiarrheal effects of aqueous extract of aerial parts of T. lucida in two experimental models and to investigate its mechanism of action. We determined the antispasmodic effect of umbelliferone and herniarin as possible bioactive components of this species
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