Variations in Essential Oil, Phenolic Compounds, and Antioxidant Activity of Tunisian Cultivated Salvia officinalis L.

Abstract

The variation in the chemical composition of the essential oil of Salvia officinalis , growing in different habitats, was studied. GC-MS analysis revealed 57 compounds representing 94.68-96.80% of total oils. The major components were alpha-thujone (11.55-19.23%), viridiflorol (9.94-19.46%), 1,8-cineole (8.85-15.60%), camphor (5.08-15.06%), manool (5.52-13.06%), beta-caryophyllene (2.63-9.24%), alpha-humulene (1.93-8.94%), and beta-thujone (5.45-6.17%), showing significant differences between different collection sites. Analysis of some representative polyphenolic compounds and antioxidant activity was performed using postdistilled dry samples. Rosmarinic acid, carnosol, and carnosic acid were the prevalent compounds of S. officinalis methanolic extracts. The results revealed differences in the polyphenolic composition and also exhibited antioxidant and radical-scavenging activities at different magnitudes of potency. However, within the used methods, only the DPPH(*) assay showed significant differences (p < 0.05) in free radical scavenging activity among samples collected in different regions. Plants collected in the coastal regions Soliman and Kelibia accumulate more polyphenolic compounds, known to be responsible for the main antioxidant activity of sage (rosmarinic acid, carnosol, and carnosic acid), than those growing inland at Bou Arada and Sers. Moreover, the former presented a higher radical-scavenging activity. The methanolic extracts of postdistilled S. officinalis might be valuable antioxidant natural sources and seemed to be applicable in both the health medicine and food industries.