title: The application of 1,8-cineole, a terpenoid oxide present in medicinal plants, inhibits castor oil-induced diarrhea in rats.
abstract: BACKGROUND
  1,8-Cineole, a terpene, characterized as a major constituent occurring in the essential oils of several aromatic plants. It is widely used in pharmaceutical industry, as a food additive and for culinary purposes.
  
  
  OBJECTIVE
  This study investigates the inhibitory effect of 1,8-cineole on transit time and diarrhea in animal models.
  
  
  METHODS
  Acute toxicity and lethality of 1-8-cineole was determined by Lork's guidelines. The antidiarrheal effect of 1,8-cineole was investigated by determining the intestinal transit and enterpooling in rats. In all experiments, different doses of 1,8-cineole (20-120 mg/kg), atropine, and loperamide were administered orally.
  
  
  RESULTS
  The LD50 of 1,8-cineole for oral administration was estimated to be 1280 mg/kg. 1,8-Cineole (20-120 mg/kg) did not show a significant decrease in small intestine transit (p > 0.05); however, the highest dose displayed a significant decrease in comparison with atropine (p < 0.05). This substance decreased the peristaltic index value to 68 ± 0.36% at a dose of 120 mg/kg compared with the control group (85.22 ± 4.31%) in the castor oil transit test. 1,8-Cineole significantly delayed the onset of diarrhea to -142.33 ± 6.08 min at 120 mg/kg, while the time was 103.66 ± 20.73 min for the control and >240 min for the loperamide. Moreover, 1,8-cineole significantly decreased intestinal fluid accumulation (p < 0.05).
  
  
  CONCLUSIONS
  This study demonstrated antispasmodic and antisecretory activities of 1,8-cineole and rationalized the traditional use of the plant containing various levels of this terpene in the treatment of gastrointestinal complains such as diarrhea.
authors.affiliation: Department of Clinical Sciences, Faculty of Veterinary Medicine, Urmia University , Urmia , Iran.
authors.forename: Ghader
authors.initials: G
authors.lastname: Jalilzadeh-Amin
authors.forename: Massoud
authors.initials: M
authors.lastname: Maham
mesh_terms: D000284:Administration, Oral; D000818:Animals; D000930:Antidiarrheals / Q000302:isolation & purification / Q000627:therapeutic use* / Q000633:toxicity; D002368:Castor Oil / Q000494:pharmacology*; D003511:Cyclohexanols / Q000302:isolation & purification / Q000627:therapeutic use* / Q000633:toxicity; D003967:Diarrhea / Q000139:chemically induced / Q000188:drug therapy*; D000077591:Eucalyptol; D005772:Gastrointestinal Transit / Q000187:drug effects; D007928:Lethal Dose 50; D008297:Male; D039821:Monoterpenes / Q000302:isolation & purification / Q000627:therapeutic use* / Q000633:toxicity; D017208:Rats, Wistar; D023382:Toxicity Tests, Acute
chemical_list: D000930:Antidiarrheals; D003511:Cyclohexanols; D039821:Monoterpenes; D002368:Castor Oil; D000077591:Eucalyptol
keywords: Antispasmodic; essential oil; in vivo; intestinal transit; terpenes