Spasmolytic Activity of the Ethanol Extract of Sideritis raeseri spp. raeseri Boiss. & Heldr. on the Isolated Rat Ileum Contractions

Sideritis raeseri spp. raeseri Boiss. & Heldr., known as "mountain tea," has been widely used in the Mediterranean region as a spice and in folk medicine as a very popular decoction because of its anti-inflammatory, carminative, analgesic, antitussive, stomachic, and antimicrobial properties. The study was aimed to investigate the effects of an ethanol extract of S. raeseri on intestinal activity. Air-dried and powdered aerial parts were extracted with 96% ethanol. The rat ileum preparations were incubated in Tyrode's solution gassed (95% O-2/5% CO2) at 37 degrees C. The ethanol extract of S. raeseri (0.03-0.3 mg/mL) relaxed spontaneous contractions in isolated rat ileum, similar to that produced by papaverine. The plant extract in a concentration-dependent manner (0.015-0.15 mg/mL) significantly inhibited the contractile response to acetylcholine (P<.01). Atropine inhibited the response to acetylcholine. A similar relaxation-inducing effect of the S. raeseri extract was observed on the precontracted ileum by histamine and barium chloride. Plant extract (0.03-0.3 mg/mL) significantly shifted the histamine concentration-response curve to the right and down (P<.01). The S. raeseri extract (0.03-0.3 mg/mL) significantly inhibited the contractions induced by barium chloride (P<.01). The results show that the ethanol extract of S. raeseri can produce inhibition of the the spontaneous rat ileum contractions and contractions induced by different spasmogens. These data indicate that S. raeseri acts as a spasmolytic on intestinal smooth muscle, which justifies its use in gastrointestinal disorders.