Chemical Composition, Antioxidant Activities and Protective Effects of Sideritis italica Extract on C2C12 Oxidative Stress

Aims: Sideritis italica is a medicinal plant used for medical purposes mainly based on experiences rather than scientific evidence. Biological properties, composition of primary and secondary metabolites as well as the antioxidant capacity were investigated on samples from wild plant.

Methodology: The ultrastructure of aerial parts and quantitative distribution of pigments, including chlorophylls and amino acids, as well as the main class of secondary metabolites (phenols, flavonoids, flavonols and proanthocyanidins) were investigated. The extracts were tested by radical scavenging assays (DPPH, ABTS) and pharmacological assays (antiproliferative activity, effects on ROS production and protective effects against DNA damage induced by hydrogen peroxide) for their effects on C2C12 cell line.

Results: Scanning electron microphotography confirms the presence of pharmacognostic characteristics, such as glandular and non-glandular trichomes on aerial parts. The chemical analysis indicates that the leaves are the most important part of the plant, and ethanol/water 70/30 is the preferable extraction solvent. The highest concentration of all metabolites was found in 70% ethanol extract of leaves. The antiradical assays and the in vitro tests on mouse myoblast cells C2C12 confirm the biological activities of the extract. C2C12 culture medium supplemented with extract, at doses (5-200μg/ml) not interfering with cell viability, was seen to modulate the ROS production and balance the increased oxidative stress induced by hydrogen peroxide. The treatment of C2C12 cells with 200 μg/ml of extract results in a percentage reduction of ROS of -60% and -71%, compared to untreated and H2O2 treated groups, respectively, P<.05. The quantitative reduction of 8-hydroxy-2’-deoxyguanosine (8-OH-dG), which is a biomarker of free radical DNA damage, confirms the protective effect of S. italica extract on oxidative stress at basal condition as well as in presence of exogenous stimuli (-11 and -7%, at 20μg/ml, respectively versus untreated and H2O2 groups, P<.05).

Conclusion: The results obtained in the present study support the rational base for the medicinal use of plant and extracts in modulating the free radical metabolism and balancing the oxidative stress.