The monoamine oxidase inhibitory activity of essential oils obtained from Eryngium species and their chemical composition

Context Monoamine oxidase (MAO) inhibitors are used in the treatment of depression, anxiety disorders, and the symptomatic treatment of Parkinson's disease. Eryngium, the most representative of the Apiaceae family, is well known for the presence of essential oils (EOs), which have already demonstrated MAO inhibitory potential.

Objective The objective of this study is to evaluate the MAO inhibitory capacity of the EOs obtained from Eryngium floribundum Cham. & Schlecht. (EF), E. eriophorum Cham. & Schlecht. (EE), E. nudicaule Lam. (EN), E. horridum Malme (EH), and E. pandanifolium Cham. & Schlecht. (EP).

Materials and methods EOs were obtained from fresh whole plants by hydrodistillation (3?h). Chemical analyses were performed by GC/MS using apolar and polar columns, with oven temperature from 60 to 300?°C at 3?°C/min. The MAO-A and -B activities were evaluated in vitro by an end-point method using kynuramine as the substrate and mitochondrial suspension or human recombinant enzymes as the enzymatic source. DMSO 2%, clorgyline 10^?7 M, and pargyline 10^?6 M were used as controls.

Results and discussion EFEO, EEEO, ENEO, EHEO, and EPEO GC/MS analysis showed (E)-caryophyllene (4.9–10.8%), germacrene D (0.6–35.1%), bicyclogermacrene (10.4–17.2), spathulenol (0.4–36.0%), and globulol (1.4–18.6%) as main constituents. None of the EOs inhibited MAO-A activity (4 and 40?μg/mL). However, EHEO inhibited MAO-B activity with an IC₅₀ value of 5.65?μg/mL (1–200?μg/mL). Pentadecane (10?μM), its major constituent (53.5%), did not display significant MAO-B inhibition.

Conclusion The study demonstrates the promising application of Eryngium species as a source of potential central nervous system bioactive secondary metabolites, specially related to neurodegenerative disorders.