Selective modulatory effects of the essential oil of Croton zehntneri on isolated smooth muscle preparations of the guinea-pig

✍ Scribed by A. N. Coelho-de-Souza; D. N. Criddle; J. H. Leal-Cardoso

• Publisher: John Wiley and Sons
• Year: 1998
• Tongue: English
• Weight: 149 KB
• Volume: 12
• Category: Article
• ISSN: 0951-418X
• DOI: 10.1002/(sici)1099-1573(199805)12:3<189::aid-ptr222>3.0.co;2-s

✦ Synopsis

The effects of the essential oil of the plant Croton zehntneri (EOCz) in the concentration range 1-200 mg/ mL were studied on the mechanical activity of various in vitro smooth muscle preparations of the guineapig. In isolated ileum EOCz induced a variable response such that in 57% of tissues basal tone was reduced (EC 50 5 mg/mL) whereas the rest remained unaffected by the oil. In concentrations above 10 mg/ mL EOCz induced spontaneous oscillatory contractions in all preparations. In contrast the basal tone of the aorta, portal vein and bladder remained unaltered by the oil. In the portal vein EOCz concentrationdependently inhibited the amplitude of spontaneous contractions (IC 50 109 mg/mL) without reducing frequency, whereas in the bladder such activity was increased by the oil (EC 50 44 mg/mL). In ileum precontracted with 60 mM KCl, EOCz induced a complete and concentration-dependent relaxation with an IC 50 value of approximately 26 mg/mL. In contrast EOCz did not relax KCl-induced tone in the aorta or bladder, whilst eliciting less than 20% relaxation of the precontracted portal vein. Thus our data show that EOCz exerts differential modulatory effects on the contractility of various smooth muscles of the guinea-pig. That EOCz appears to selectively relax intestinal smooth muscle may support its use in folk medicine as a gastrointestinal antispasmodic.