Antispasmodic effect of Mentha piperita essential oil on tracheal smooth muscle of rats

Peppermint oil exhibited antispasmodic activity on rat trachea involving prostaglandins and nitric oxide synthase. Mentha piperita is a plant popularly known in Brazil as “hortelã-pimenta” whose essential oil is used in folk medicine for its anti-inflammatory, antispasmodic, expectorant actions and anti-congestive. Here, it was investigated the effect of Mentha piperita essential oil (peppermint oil) in rat tracheal rings along with its mechanism of action. Tracheal tissue from Male Wistar rats (250–300 g) were used. Peppermint oil was added in cumulative concentrations [1–300 μg/ml] to the tissue basal tonus or pre-contracted by carbachol [10 μM] at 10 min intervals, incubated or not with indomethacin [10 μM], l-N-metyl-nitro-arginine [100 μM], hexamethonium [500 μM], or tetraethylammonium [5mM]. Peppermint oil [100 and 300 μg/ml] inhibited the contractions induced by carbachol, which was reversed by indomethacin, l-N-metyl-nitro-arginine and hexamethonium, but not by tetraethylammonium. These data suggest the participation of prostaglandin E 2, nitric oxide and autonomic ganglions in the peppermint oil relaxant effect and may be correlated with its popular use in respiratory diseases. Peppermint oil exhibited antispasmodic activity on rat trachea involving prostaglandins and nitric oxide synthase.