The essential oil from the twigs of Cinnamomum cassia Presl inhibits oxytocin-induced uterine contraction in vitro and in vivo.

ETHNOPHARMACOLOGICAL RELEVANCE: The twigs and bark of Cinnamomum cassia Presl (Lauraceae) are widely used in traditional Chinese medicine in the treatment of tumor, abdominal pain, dysmenorrhea, digestive system disease and inflammatory diseases. The aim of this study was to determine the inhibitory effect of the essential oil from the twigs of Cinnamomum cassia Presl (EOCC) on uterine contraction in vitro and in vivo. MATERIALS AND METHODS: The Institute of Cancer Research (ICR) mouse uterine contraction was induced by oxytocin (OT) exposure following estradiol benzoate pretreatment. Mice were given the EOCC (60, 30, and 15mg/kg) by gavage. The level of prostaglandin F2α (PGF2α) in uterine tissue were determined according to specification of enzyme linked immunosorbent assay (ELISA) kit. Uterine tissue was collected for histopathological analysis (H&E). Myosin light chain 20 (MLC20), phosphorylation of myosin light chain 20 (p-MLC20) and cyclooxygenase-2 (COX-2) proteins in uterine tissue were assessed by Western Blot. Mouse isolated uterus strips were mounted in tissue organ baths containing Locke's solution. The contractile responses were recorded with Power Lab recording system. The effect of the EOCC on uterine contraction induced by OT, PGF2α, and acetylcholine (Ach) was observed. Myometrial cells were exposed to OT (7µM) to induce Ca2+ release, and the effect of the EOCC (100, 50, and 25µg/ml) on intracellular Ca2+ was analysed with fluorometry imaging. RESULTS: In vivo study demonstrated that the EOCC significantly reduced OT-induced writhing responses with a maximal inhibition of 66.5%. It also decreased the level of PGF2α in OT-induced mice uterine tissue. Moreover, Western blot analysis showed that COX-2 and p-MLC20 expressions in uterine tissue of dysmenorrhea mice were significantly reduced. EOCC inhibited spontaneous uterus contractions in a dose-dependent manner, and the concentration of the EOCC giving 50% of maximal contraction (IC50) value was 61.3µg/ml. The IC50 values of the EOCC on OT, PGF2α, and Ach-induced contractions were 113.0µg/ml, 94.7µg/ml, and 61.5µg/ml, respectively. Further in vitro studies indicated that the EOCC could restrain intracellular Ca2+ levels in favour of uterine relaxation. CONCLUSION: Both in vivo and in vitro results suggest that the EOCC possesses significant spasmolytic effect on uterine contraction. Thus, the EOCC yields a possible therapeutic choice for the prevention and treatment of primary dysmenorrhea.

The essential oil from the twigs of Cinnamomum cassia Presl alleviates pain and inflammation in mice.

ETHNOPHARMACOLOGICAL RELEVANCE: Cinnamomum cassia Presl (Lauraceae) can be found southern China and its bark is commonly used for centuries as ingredient in food and cosmetic industry. The twigs of Cinnamomum cassia Presl is popularly used in China to treat inflammatory processes, pain, menstrual disorders, hypertension, fever etc. The aim of this study is to evaluate the antinociceptive and anti-inflammatory properties of the essential oil (EO) from the twigs of Cinnamomum cassia Presl. MATERIAL AND METHODS: The chemical characterization of the EO was performed by gas chromatography coupled with mass spectrometry (GC-MS). The EO doses of 15, 30, and 60mg/kg were employed in the biological assays. The antinociceptive effects of the EO were evaluated using the models of acetic acid-induced writhing, oxytocin-induced writhing, and formalin and complete Freund's adjuvant (CFA) -induced overt pain tests. we also investigated the effect of the EO in pain intensity to a mechanical stimulus (mechanical hyperalgesia) after carrageenan by using an electronic version of von Frey filaments. Evaluation of anti-inflammatory activity was based on paw edema induced by carrageenan (300µg/25µL/paw) in mice. The levels of cytokines, NO, and PGE2 in paw skin tissue were determined according to instructions. COX-2 and iNOS proteins in paw skin tissue were assessed by Western Blot. RESULTS: The EO (15, 30, and 60mg/kg) reduced the number of abdominal writhings induced by acetic acid with inhibition of 38.0%, 55.4% and 58.7%, respectively. The EO (15, 30, and 60mg/kg) also reduced the number of abdominal writhings induced by oxytocin with inhibition of 27.3%, 51.7% and 69.0%, respectively. The EO significant inhibited the inflammatory (second phase: 10-30min) phase of the formalin-induced paw flinching and licking at the doses of 15, 30, and 60mg/kg. The EO at the tested doses of 15, 30, and 60mg/kg showed inhibited CFA-induced paw flinching and licking. The EO (15, 30, and 60mg/kg) also inhibited carrageenan-induced mechanical hyperalgesia and paw edema. It also decreased the levels of cytokines (TNF-α, and IL-1ß), NO, and PGE2 in carrageenan-induced mice paw skin tissue. Moreover, Western blot analysis showed that COX-2 and iNOS expressions in paw skin tissue of mice were significantly reduced. CONCLUSIONS: These results demonstrate that the antinociceptive and anti-inflammatory properties of the EO from the twigs of Cinnamomum cassia Presl, corroborating its use in folk medicine.