Supercritical CO2 extracts and essential oils from Teucrium polium L. growing in Algeria: chemical composition and antioxidant activity

In this work, we studied the essential oils (EOs) obtained by hydrodistillation and lipophilic fractions extrated by carbon dioxide supercritical fluid extraction (SFE-CO2) from Teucrium polium (Lamiaceae). EOs and SFE-CO2 extracts were analyzed by GC and GC-TOFMS. EOs showed qualitative differences compared with SFE-CO2 extracts, though in both products germacrene D was the most abundant component. Notably a new EO chemotype, characterzed by germacrene D, β-eudesmol, shyobunol, and δ-cadinene, was reported. EOs along with SFE-CO2 extracts, plant powder, and solid residue after SFE were evaluated for total phenolic content (TPC) and antioxdiant activity by DPPH, FRAP, and ORAC assays. The raw plant material was the most active, followed by the solid residue after SFE-CO2 extraction. On the other hand, EO and SFE-CO2 extracts displayed weak activity. These results showed that the antioxidant compounds of T. polium are of hydrophilic nature and are not extracted or retained in the plant material after SFE-CO2 extraction.