Carvone is a monoterpene ketone that occurs naturally as (R)-(-) and (S)-(+) enantiomers in some essential oils that are used in the food and flavour industry and in folk medicine for the treatment of digestive disorders. However, the actions of carvone enantiomers on the gastrointestinal motility in vivo models are not well known. The effects of (R)-(-)-and (S)-(+)-carvone on gut motility were evaluated in mice by measuring gastric dye emptying and the rate of intestinal transit. It was also evaluated by measuring intragastric pressure monitored in vivo, and the contractile behaviour of gut strips from mice was studied in vitro.(R)-(-)-carvone and (S)-(+)-carvone caused gastric retention, reflected by decreased gastric dye emptying. These effects were accompanied by a reduction of the propulsive behaviour of the small intestine. The retarding effects of carvone on gastric emptying were also related to a decrease in the magnitude of intragastric pressure waves. The carvone-induced effects in vivo resembled those of the positive control, loperamide. In vitro, carvone relaxed sustained contractions induced by carbachol in strips of longitudinal gastric fundus and duodenum. In fundic strips under Ca 2+ -free conditions, (S)-(+)-carvone inhibited both the phasic and tonic phases of carbachol-induced contractions and contractions caused by electrical field stimulation. Carvone inhibited duodenal tissues more than gastric tissues, especially when plasmalemmal Ca 2+ influx was pharmacologically stimulated. Both enantiomers (R)-(-)-carvone and (S)-(+)-carvone exerted myorelaxant and antispasmodic effects on gut smooth muscle in vitro and inhibited gastrointestinal motility in awake mice.

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