Chemical Composition and Antioxidant, Anti-Inflammatory and Anticholinesterase Properties of the Aerial and Root Parts of Centaurea acaulis Essential Oils: Study of the Combinatorial Activities of Aplotaxene with Reference Standards

Abstract

In recent years, growing attention has been given to essential oils. Essential oils obtained from medicinal plants show high therapeutic potential against various types of pathologies, including Alzheimer's, cancer and inflammatory diseases. The purpose of this work was to study the chemical composition of the aerial and root parts of Centaurea acaulis essential oils by GC/FID and GC/MS, to evaluate the anti-inflammatory, antioxidant and neuroprotective properties, and in-vitro combinatory effect of aplotaxene isolated from the roots with reference standards, in order to find new and more effective agents for the treatment of degenerative and inflammatory diseases. The statistical analysis clustered the essential oil aerial parts into two distinct groups. The specimens characterized by a humid climate and low altitude was mainly discriminated by the high contents of (E)-β-caryophyllene (3.4-8.4%), hexadecanoic acid (6.3-10.8%) and caryophyllene oxide (6.2-9.9%). While the second group characterized by a humid climate and higher altitudes was characterized by high levels of limonene (15.2-19.2%) and τ-muurolol (12.6-17.2%). In contrast, essential oils of roots were dominated by aplotaxene whatever the climate type. All samples showed very good antioxidant and anti-inflammatory activities. The combination of aplotaxene with references gave synergistic effects with excellent activities about 2 times higher than the synthetic references. The neuroprotective activity of essential oils and aplotaxene did not show inhibition against AChE, whereas they inhibited BChE with IC50 values comparable to Galantamine.