In vitro evaluation of antiatherogenic potential of Origanum × paniculatum, Lippia alba, Clinopodium nepeta, and Eucalyptus globulus essential oils

Abstract

Introduction: Essential oils (EOs) are mixtures of secondary plant metabolism compounds with potential lipid-lowering activity and antioxidant properties. They may therefore be considered as add-on therapy for the prevention and treatment of cardiovascular diseases. Methods: EOs of Origanum × paniculatum (OpEO), Lippia alba (chemotype linalool) (LaLEO), Clinopodium nepeta (CnEO) and Eucalyptus globulus (EgEO), were evaluated on THP-1 foam cell macrophages as a cellular model of atherogenesis. Cell viability was determined by the MTT assay, lipid content by thin-layer chromatography, and Oil Red O staining. Antioxidant activity was evaluated by TBARS on low-density lipoprotein lipid peroxidation, and by ABTS•+, DPPH•, and FRAP assays. EOs were characterised by gas chromatography–mass spectrometry and a predictive multivariate data analysis was performed by partial least square regression (PLS) to identify the components related to antiatherogenic potential. Results: OpEO reduced foam cell viability (IC50 = 45 µl/l) and cholesterol and triacylglycerol content and demonstrated antioxidant activity. In contrast, LaLEO increased lipid content and showed a prooxidant capacity with low reduction of cell viability (IC50 = 340 µl/l). CnEO showed prooxidant activity and reduction of cell viability (IC50 = 130 µl/l) without changes in lipid content. EgEO showed antioxidant activity, lipid increase, and low cytotoxicity (IC50 = 770 µl/l). PLS analysis suggests that cis-sabinene hydrate is responsible for cell viability inhibition, thymol and β-cis-terpineol decrease lipid content and possess antioxidant activity, and linalool increases lipid levels and has prooxidant capacity. Conclusions: OpEO is a promising natural product for therapy against atherosclerosis, with cis-sabinene hydrate, thymol, and β-cis-terpineol as potential active principles.