Major selected monoterpenes α-pinene and 1,8-cineole found in Salvia lavandulifolia (Spanish sage) essential oil as regulators of cellular redox balance

Abstract

Context: Salvia lavandulifolia has been employed in folk medicine for the treatment of memory and dementia problems. This specie contains numerous bioactive terpenes which may contribute to its effectiveness.

Objective: To analyze the composition of essential oil of S. lavandulifolia and to investigate the potential in vitro cytoprotective and antioxidant activities of its major compounds, α-pinene and 1,8-cineole, against H2O2-induced oxidative stress in the U373-MG cell line.

Materials and methods: Chemical composition was analyzed by gas chromatography; antioxidant capacity was measured using the ORAC assay, and cytoprotective activity was evaluated using the MTT assay (for cell viability) (range of concentrations: 10-400 μM), DCFH-DA assay (for intracellular ROS generation), thiobarbituric acid reactive substances (TBARS) method (for lipid peroxidation), and spectrofometric techniques and Western blot (for enzymatic activity and protein expression, respectively) at 10 and 25 µM.

Results: α-Pinene (18.39%) and 1,8-cineole (19.57%) were identified as major compounds in S. lavandulifolia essential oil. Pretreatments with these monoterpenes protected U373-MG cells against H2O2-induced oxidative injury by attenuating the loss of cell viability (IC50 : 79.70 µM to α-pinene and 66.23 µM to 1,8-cineole) and cell morphology, inhibiting ROS production (the most active compound was 1,8-cineole by decreasing the ROS production over 30-45% at 10 and 25 μM) and lipid peroxidation and increasing the endogenous antioxidant status (glutathione levels and CAT, SOD, GR, GPx, and HO-1 activity and protein expression).

Conclusions: These findings demonstrate for the first time the effects of the monoterpenes 1,8-cineole and α-pinene identified in S. lavandulifolia essential oil as regulators of cellular redox balance in astrocytes.

Keywords: Antioxidant; astrocytes; medicinal plant; oxidative stress.