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Gastrointestinal effects of Ocimum selloi essential oil is mediated by calcium channel blockade and potassium channel activation
Ocimum selloi is an aromatic herbaceous plant popularly used as an antispasmodic and antidiarrheic in Brazil . Here, the gastrointestinal and analgesic effects of Ocimum selloi essential oil (EO) were investigated in mice. In addition, the response and the mechanism of action of EO were evaluated in the terminal segments of the guinea-pig ileum. The main component detected in the EO was methyl chavicol (98%; GC and GC/MS). In mice, the EO (2, 20, 200mg/kg; p.o.) showed a significant and dose-dependent anti-diarrhea (p>0.05- p<0.001) and antinociceptive effects (p>0.05- p<0.001; in the acetic acid 0.6% induced writhings model). In the guinea-pig ileum, the essential oil (0.005–500µg/ml) reduced, in a concentration-dependent way, the contraction induced by K+ 25 mM (IC50=250µg/mL). This spasmolytic response was reversed by glibenclamide (10µM). The EO (0.005–500µg/ml) also reduced, in a concentration-dependent manner (IC50=210µg/mL), the contraction induced by high K+ concentration (60 mM). In the calcium chloride concentration-response curve, the incubation with EO (10µg/ml) caused a rightward shift by about one order without significantly depressing the maximum responses (p>0.05). The EO (0.005–500µg/ml) did not modify the basal tonus of the ileum. In summary, Ocimum selloi essential oil showed analgesic effect in a model of visceral pain, anti-diarrhea effect and a spasmolytic action, due mainly to a potassium channel opener and calcium channel blocker actions. These results provide further support for O. selloi popular usage in gastrointestinal disorders.
Acknowledgements: CNPq, CAPES.
References: 1. Moraes, L.A.S. et al (2002) Annals of the Brazilian Academy of Sciences 74: 183–186.