Chemical composition and anti-inflammatory activity of the essential oils of Piper gaudichaudianum and Piper mikanianum

Ethnopharmacological relevance: Inflammation is the body's normal protective response to injury and is stimulated by pathogens, toxic compounds, damaged cells or radiation, promoting healing and restoring homeostasis to the injured tissue. Leaves of Piper gaudichaudianum Kunth, known as pariparoba are widely used in folk medicine for the relief of toothache, while the fresh roots are used as anti-inflammatory and to treat liver disorders. For P. mikanianum (Kunth) Steud is known as aguaxima, is widely used in the treatment of inflammation, rheumatism and ulcer, with its roots being used for stomach disorders and as a diaphoretic in intermittent fevers. Aim of the study: Therefore, this work aims to chemically characterize the essential oil of Piper gaudichaudianum and Piper mikanianum, as well as the evaluation of neutrophil antichemotactic activity of both essential oils in order to complement the information of its traditional use, taking the leaves as plant material and, with that, corroborating its use in folk medicine for the treatment of inflammatory diseases. Materials and methods: The essential oil from leaves of both Piper species were obtained from crushed fresh samples, by hydrodistillation using a Clevenger type-apparatus for 4 h. The yield determination was performed as vol/wt (v/w) and in triplicate. The amount of essential oil obtained was quantified in mL. The identification and quantification of the compounds was performed using gas chromatography-mass spectrometry (GC-MS) and gas chromatography-flame ionization detection (GC-FID). The in vitro anti-inflammatory activity was evaluated using the model of modified Boyden chamber. In this test the essential oils were tested for their ability to inhibit leukocyte chemotaxis stimulated by Escherichia coli lipopolysaccharide. Results: The chemical composition of the essential oils revealed the identification of 26 constituents for P. gaudichaudianum being the sesquiterpenes ss-selinene (14.0%) and viridiflorene (10.5%) the main compounds, followed by caryophyllene oxide (9.3%) and (E)-nerolidol (9.0%). For P. mikanianum essential oil, ss-myrcene (17.2%) and bicyclogermacrene (26.3%) were the major components in the monoterpenes and sesquiterpene fractions, respectively. The essential oils were also tested for their ability to inhibit neutrophil chemotaxis in vitro when stimulated by Escherichia coli lipopolysaccharide. Both essential oils showed antichemotactic effect with reduction in migration of 0-72.2% for P. gaudichaudianum and 8.6-100% for P. mikanianum to same concentrations, suggesting a response to acute inflammatory processes. Conclusions: Since up to date there is no report of this biological activities by this mechanism (antichemotactic assay) for essential oils this species. These results showed that the essential oils of P. gaudichaudianum and P. mikanianum have a great capacity to inhibit neutrophil chemotaxis in an inflammatory process, in a dosedependent way, suggesting anti-inflammatory potential, by preventing its accumulation at the injury site with the possibility of tissue damage. Findings of these studies support the traditional use of these species in the treatment of inflammatory processes.

Automated summary

This study chemically characterized the essential oils of Piper gaudichaudianum and Piper mikanianum, and evaluated their neutrophil antichemotactic activity. The results showed that these essential oils have a strong ability to inhibit neutrophil chemotaxis, indicating their potential anti-inflammatory effects.