In vitro anti-inflammatory activity of terpenes via suppression of superoxide and nitric oxide generation and the NF-κB signalling pathway

Abstract

Background and Aims

Terpenes are considered the main components of essential oils and an important source for the identification of novel lead molecules. This study aimed to investigate the in vitro anti-inflammatory activity of l-carveol, l-carvone, and m-cimene (monoterpenes) and of valencene and guaiene (sesquiterpenes).

Methods

The influence on intracellular nitric oxide (NO) and pro- and anti-inflammatory cytokine (TNF-α, IL-1α and IL-10) production and on nuclear factor kappa B (NF-κB) activity was determined using Griess reagent, immunoenzymatic assay kits (ELISA) and chemiluminescence measurements in cell-based assays, respectively. Antioxidant activity was assayed through the protective effect against cellular oxidative damage produced by superoxide anion production (O ₂^·−) and hydrogen peroxide on macrophages and by the quenching activity of the NO radical.

Results and Discussion

Terpenes reduced the pro-inflammatory cytokines TNF-α and IL-1α and increased the production of IL-10. In addition, the terpenes, especially guaiene (53.3 ± 2.4%) and m-cymene (38.1 ± 0.6%), significantly inhibited NO production in a macrophage cell culture-based assay, whereas no effect was observed in the scavenging activity of this radical. l-carveol and m-cymene significantly inhibited O ₂^·− production with reductions of approximately 68.6 ± 2.2% and 48.2 ± 4.2%, respectively, at a concentration of 10 μM. Moreover, these terpenes were verified to suppress NF-κB activity. The results indicate that these terpenes have therapeutic potential and may be used to suppress inflammatory diseases or as a leading compounds.