The effect of thymol on acetylcholine-induced contractions of the rat ileum and uterus under ex vivo conditions

Abstract

Thyme (Thymus vulgaris L.) is a well-known medicinal plant, the aerial parts of which have long been used internally or externally as a traditional remedy for various diseases. Thyme essential oils have important pharmaceutical applications and are regularly used in the pharmaceutical, food and cosmetic industries. In folk medicine, thyme preparations are used to treat respiratory, digestive, cardiovascular and nervous disorders, as well as to relieve dysmenorrhea. Thymol, a major constituent of Thymus vulgaris essential oil, has been shown to affect skeletal and smooth muscle excitation and contraction. Therefore, the main objective of this study was to evaluate its effect on acetylcholine (ACh)-induced rat intestinal and uterine preparations. Isolated ileum and uterine horn preparations were placed in a 20-ml organ bath containing Tyrode or De Jalon solution and exposed to graded concentrations of ACh (0.036, 0.109, 0.36, 1.09, 3,6, 10.9, and 36 μM) and either 0.02 or 0.2 mM thymol. Additionally, the dose–response relationship of thymol impact on intestinal and uterine contraction was evaluated. Contraction changes were monitored using an isometric transducer. Thymol at the higher dose (0.2 mM) significantly reduced ACh-induced intestinal and uterine contractions. Thus, this study provides new important data on competitive actions between thymol and ACh. In the dose–response study, the IC50 values were calculated as 5.26 mM for the ileum and 5.35 mM for the uterus. Our results demonstrated the efficacy of thymol in reducing ileal and uterine smooth muscle contractions, thus supporting the use of thyme in traditional medicine in the treatment of digestive disorders and painful menstrual cramps.

Relaxant effect of thymol on smooth muscle

“…Thymol mechanisms of action are not completely defined or understood; however, some authors have proposed hypotheses about its influence on smooth muscle relaxation ranging from calcium channel blockade to concentration-dependent inhibition of muscarinic Ach receptors. 34,36,43 Nevertheless, results of the study demonstrated that thymol micro concentrations reduce Ca 2+-ATPase activity and increase Ca 2+ permeability in the sarcoplasmic membrane; on the other hand, they show that this compound exerts an agonists effect on α1, α2, and β adrenergic receptors in guinea pig portal vein and stomach isolated tissue producing a relaxing effect on them, these results suggest that the molecule's action mechanism differs depending on smooth muscle type. 41 The evidence to understand thymol's action mechanism on smooth tissue is scarce, so these mechanisms have been investigated in different tissues or cell lines.…”

Effect of photobiomodulation on alleviating primary dysmenorrhea caused by PGF2α

“…The rise of intracellular calcium concentration is central to the function of smooth muscle, including uterine smooth muscle [50]. Hormones, neurotransmitters, and pharmacologic agents influence the contractile state of uterine smooth muscle cells, and the ability of any of these agents to affect response is governed by the final common pathway of Ca 2+ ion mobilization, which couples excitation to contraction [51]. Our experiments revealed that the induction of prostaglandin-F 2α resulted in an elevation in the Ca 2+ levels in HUSM cells.…”