Antispasmodic and myorelaxant effects of the flavoring agent methyl cinnamate in gut: potential inhibition of tyrosine kinase

A Phytochemical Constituent, (E)-Methyl-Cinnamate Isolated from Alpinia katsumadai Hayata Suppresses Cell Survival, Migration, and Differentiation in Pre-Osteoblasts

BACKGROUND

(E)-methyl-cinnamate (EMC), a phytochemical constituent isolated from Alpinia katsumadai Hayata, is a natural flavor compound with anti-inflammatory properties, which is widely used in the food and commodity industry. However, the pharmacological effects of methyl-cinnamate on pre-osteoblasts remain unknown. This study aimed to investigate the pharmacological effects and mechanisms of EMC in pre-osteoblast MC3T3-E1 cells (pre-osteoblasts).

METHODS

Cell viability and apoptosis were evaluated using the MTT assay and TUNEL staining. Cell migration and osteoblast differentiation were examined using migration assays, as well as alkaline phosphatase activity and staining assays. Western blot analysis was used to examine intracellular signaling pathways and apoptotic proteins.

RESULTS

EMC decreased cell viability with morphological changes and increased apoptosis in pre-osteoblasts. EMC also induced the cleavage of Poly (ADP-ribose) polymerase (PARP) and caspase-3 and reduced the expression of anti-apoptotic proteins. In addition, EMC increased TUNEL-positive cells in pre-osteoblasts, decreased the activation of mitogen-activated protein kinases, and suppressed cell migration rate in pre-osteoblasts. Subsequently, EMC inhibited the osteoblast differentiation of pre-osteoblasts, as assessed by alkaline phosphatase staining and activity assays.

CONCLUSION

These findings demonstrate that EMC has a pharmacological and biological role in cell survival, migration, and osteoblast differentiation. It suggests that EMC might be a potential phytomedicine for treating abnormalities of osteoblast function in bone diseases.

Methyl cinnamate alleviated CCI-induced upregualtion of spinal AMPA receptors and pain hypersensitivity by targeting AMPK

Various studies proved spinal AMPA receptors were involved in the formation of neuropathic pain. In this study, we investigated the effect of methyl cinnamate (MC), a flavoring agent widely used in food and commodity industry, on CCI-induced upregulation of spinal AMPARs and pain hypersensitive behaviors. Results indicated that MC treatment dosage-dependently inhibited CCI-induced mechanical and thermal hypersensitivity. To further investigate the effect of MC after the formation of neuropathic pain, MC at the dosage of 100 mg/kg was administrated on day 7-14 on CCI rats. Results showed that MC treatment for seven days alleviated CCI-induced pain hypersensitivity after the formation of neuropathic pain. MC treatment reversed CCI-induced upregulation of GluR2, GluR3 and phosphorylation of GluR1. Further, MC dosage-dependently alleviated CCI-induced activation of mTOR and the downstream p70s6k. MC dosage-dependently induced activation of AMPK. All the MC-induced effects in CCI rats were completely reversed by Compound C, a AMPK inhibitor. These results meant MC treatment mitigated CCI-induced upregualtion of spinal AMPA receptors and pain hypersensitive behaviors through actviation of AMPK.