Anti-inflammatory potential of the essential oil of the Iberian endemism Thymus carnosus

Thymus L. is an important genus of the Lamiaceae family that comprises essential oil producing plants very relevant to the food, cosmetic, perfumery and pharmaceutical industries. Despite this popularity, some species remain poorly valued. Considering the economic potential of the genera and the sparse information on Thymus carnosus, an endemic species of the Iberian Peninsula, the anti-inflammatory activity and safety profile of its essential oil were assessed. The essential oil obtained by hydrodistillation and analysed by GC and GC/MS was characterized by high amounts of monoterpenes, being borneol (29%), camphene (17.5%) and terpinen-4-ol (9%) the main compounds. For the anti-inflammatory activity, an in vitro model of lipopolysaccharide-stimulated macrophages (Raw 264.7) was used and the inhibition of nitric oxide (NO) production quantified. Assessment of the oil's cytotoxicity was performed using the MTT reduction assay on mammalian cell lines, namely macrophages, keratinocytes (HaCat) and hepatocytes (HepG2). Both bioactive and safe concentrations were disclosed (0.32µL/mL) supporting further investigations for the development of a terpene-based anti-inflammatory agent. Taken together our results show evidence on the anti-inflammatory and safety profile of T. carnosus essential oil and additional experiments are being conducted to determine the mechanism of action of the oil, namely its effect at transcriptional and translational levels of pro-inflammatory mediators as well as its effect on selective pro-inflammatory signaling cascades.

Acknowledgements: This work was funded through national funds from FCT – Fundação para a Ciência e Tecnologia under the project CEF/POCI2010/FEDER.

Keywords: Thymus carnosus, essential oil, anti-inflamatory, cell viability