In vitro Anti-inflammatory Effects of Satureja Kkhuzestanica Essential Oil Compared to Carvacrol

Satureja khozestanica grows mainly in the southwest part of Iran as a native plant. This edible herb contains various compounds including the S. Khuzestanica essential oil (SKEO) and monoterpene known as Carvacrol. Previous studies have shown the anti-inflammatory effects of S. Khuzestanica without mentioning the exact mechanism of its function. Given that prostaglandin synthesis, which is one of the main mediators of inflammation, is regulated by the cyclooxygenase-2 (COX2) gene, the present study investigated the effects of SKEO and Carvacrol on the expression of the COX2 gene in the stimulated-J774A.1 macrophage cell line.

To this end, fresh aerial parts of the plant were processed to prepare SKEO. Then, different doses of SKEO and Carvacrol (i.e., 0.004%, 0.008%, and 0.016% v/v) were used to treat with the lipopolysaccharides (LPS)-stimulated cell line for eight hours. After RNA extraction, the real-time polymerase chain reaction technique was applied for gene expression analysis.

In the LPS-stimulated J774A.1 macrophage cell line, COX2 gene expression reduced significantly in a dose-dependent manner (0.004%, 0.008%, and 0.016%, P = 0.024, P = 0.021, and P = 0.013 v/v of SKEO, respectively) by SKEO, and the effect of Carvacrol was less powerful (0.008% and 0.016%, P = 0.027 and P = 0.038 v/v, respectively) compared to SKEO. Finally, the comparison between SKEO and Carvacrol showed higher significant inhibitory effects of SKEO on COX2 gene expression in comparison with Carvacrol in 0.004% v/v concentration (P = 0.037).

In general, SKEO significantly reduced COX2 gene expression, thus it can be suggested that its anti-inflammatory effect may result from the inhibition of the synthesis of this pro-inflammatory gene.