Published online Nov 21, 2020. doi: 10.3748/wjg.v26.i43.6795
Peer-review started: May 20, 2020
First decision: July 29, 2020
Revised: August 12, 2020
Accepted: October 1, 2020
Article in press: October 1, 2020
Published online: November 21, 2020
(-)-Fenchone is a bicyclic monoterpene present in essential oils of plant species, such as Foeniculum vulgare and Peumus boldus, used to treatment of gastrointestinal diseases. Pharmacological studies report its anti-inflammatory, antioxidant, and antinociceptive activity.
To investigate antidiarrheal activity related to gastrointestinal motility, intestinal secretion and antimicrobial activity.
A castor oil-induced diarrhea model was used to evaluate antidiarrheal activity. Intestinal transit and gastric emptying protocols were used to assess a possible antimotility effect. Muscarinic receptors, presynaptic α2-adrenergic and tissue adrenergic receptors, KATP channels, nitric oxide were investigated to uncover antimotility mechanisms of action and castor oil-induced enteropooling to elucidate antisecretory mechanisms. The antimicrobial activity was evaluated in the minimum inhibitory concentration model, the fractional inhibitory concentration index using the (-)-fenchone association method with standard antifungal agents.
(-)-Fenchone (75, 150 and 300 mg/kg) showed antidiarrheal activity, with a significant decrease in the evacuation index. This activity is possibly related to a percentage of reduced intestinal transit (75, 150 and 300 mg/kg). The antimotility effect of (-)-fenchone decreased in the presence of pilocarpine, yohimbine, propranolol, L-NG-nitroarginine methyl ester or glibenclamide. In the enteropooling model, no reduction in intestinal fluid weight was observed. (-)- Fenchone did not show antibacterial activity; on the other hand, inhibits the growth of strains of fungi with a minimum fungicide concentration of 32 μg/mL. However, when it was associated with amphotericin B, no synergism was observed.
The antidiarrheal effect of (-)-fenchone in this study involves antimotility effect and not involve antisecretory mechanisms. (-)-Fenchone presents antifungal activity; however, it did not show antibacterial activity.
Core Tip: (-)-Fenchone is a bicyclic monoterpene present in essential oils of plant species, such as Foeniculum vulgare and Peumus boldus, used to treatment of gastrointestinal diseases. Diarrhea is a pathological condition characterized by an increase in three or more defecations in 24 h, being of multiple origins, whether infectious or not. In the search for new therapeutic alternatives, natural products, and medicinal plants are of great relevance. Many species of plants and their isolated compounds, including terpenes, have shown promising antidiarrheal and motility, based on this result, the monoterpene (-)-fenchone was selected for this study.