Anti-inflammation activity of fruit essential oil from Cinnamomum insularimontanum Hayata

In this study, the fruit essential oil of Cinnamomum insularimontanum was prepared by using water distillation. Followed by GC–MS analysis, the composition of fruit essential oil was characterized. The main constituents of essential oil were α-pinene (9.45%), camphene (1.70%), β-pinene (4.30%), limonene (1.76%), citronellal (24.64%), citronellol (16.78%), and citral (35.89%). According to the results obtained from nitric oxide (NO) inhibitory activity assay, crude essential oil and its dominant compound (citral) presented the significant NO production inhibitory activity, IC50 of crude essential oil and citral were 18.68 and 13.18 μg/mL, respectively. Moreover, based on the results obtained from the protein expression assay, the expression of IKK, iNOS, and nuclear NF-κB was decreased and IκBα was increased in dose-dependent manners, it proved that the anti-inflammatory mechanism of citral was blocked via the NF-κB pathway, but it could not efficiently suppress the activity on COX-2. In addition, citral exhibited a potent anti-inflammatory activity in the assay of croton oil-induced mice ear edema, when the dosage was 0.1 and 0.3 mg per ear, the inflammation would reduce to 22% and 83%, respectively. The results presented that the fruit essential oil of C. insularimontanum and/or citral may have a great potential to develop the anti-inflammatory medicine in the future.