Profiling of essential oils and polyphenolics of Salvia argentea and evaluation of its by-products antioxidant activity

The objective of this study was to examine the chemical composition of essential oils and polyphenolics and to evaluate the antioxidant capacity of S. argentea by-products. Fourty seven compounds, representing (90.13, 92.00%) of the total oil, were identified. The major components were showed to be viridiflorol (18.75, 26.93%), manool (6.15, 13.59%), α-thujone (7.30, 8.06%), p-cymene (4.17, 6.39%) and α-humulene (4.13, 5.28%). Post-distilled dry plants were considered for HPLC analysis and antioxidant capacities estimation. S. argentea methanolic extracts from both collection sites (Sers and Makther) were dominated by methyl carnosate (1377.03, 715.41 μg/g DW), rosmarinic acid (941.81, 613.25 μg/g DW) and naringenin (432.00, 356.10 μg/g DW). Higher antioxidant activity was observed in S. argentea post-distilled samples collected in Sers, as assessed by DPPH, ABTS, FRAP. Significant correlations were detected between several phenolic compounds, total phenolic amounts and the DPPH and FRAP assays. Variations in volatile compounds, phenolics and antioxidant capacity were significant between the two analyzed collection sites.

► Salvia species constitute a source of bioactive compounds.
► Viridiflorol, manool, α-thujone, p-cymene and α-humulene were the main constituents of S. argentea essential oils.
► Methyl carnosate, rosmarinic acid and naringenin were the most abundant phenolic compounds of S. argentea by-products.
► Sers methanolic extracts revealed the best antioxidant activity.
► Collection site showed a significant effect on essential oil and phenolic contents and on the antioxidant activities.