Eugenol and liposome-based nanocarriers loaded with eugenol protect against anxiolytic disorder via down regulation of neurokinin-1 receptors in mice.

Anxiety disorder is a psychiatric disorder characterized by extreme fear or worry. It is highly prevalent worldwide which affects daily life and is also an enormous health burden. Neurokinin 1 receptor (NK1R) is a G protein coupled receptor, expressed in both central and peripheral nervous system, involved in affective behaviors. NK1R has established role in anxiety and it is also an important target for pathogenesis of anxiety disorder. Therefore, it has been hypothesized in previous studies that the blockades of NK1R may have antidepressant and anxiolytic effects. The present study deals with the molecular mechanism of protective activity of eugenol against anxiolytic disorder. A pre-clinical animal study was performed on 42 BALB/c mice. Animals were given stress through conventional restrain model. The mRNA expression of NK1R was analyzed by real time RT-PCR. Moreover, the NK1R protein expression was also examined by immunohistochemistry in whole brain and mean density was calculated. The mRNA and protein expressions were found to be increased in animals given anxiety as compared to the normal control. Whereas, the expressions were decreased in the animals treated with eugenol and its liposome-based nanocarriers in a dose dependent manner. However, the results were better in animals treated with nanocarriers as compared to the compound alone. It is concluded that the eugenol and its liposome-based nanocarriers exert anxiolytic activity by down-regulating NK1R protein expression in mice.