Biological Activities of Essential Oils and Ethanol Extracts of<i>Teucrium polium</i>subsp.<i>capitatum</i>(L.) Briq. and<i>Origanum floribundum</i>Munby

Abstract

The present study was conducted to evaluate the in vitro antioxidant, anti-inflammatory and antimicrobial activities of the essential oils and crude ethanol extracts of Teucrium polium subsp. capitatum Briq. and Origanum floribundum Munby from Algeria. A total of 78 and 55 constituents were identified, representing 92 and 98.4 % of the total chemical composition of Teucrium and Origanum essential oils, respectively. Monoterpenes (22 %), sesquiterpenes (31.2 %) and oxygenated sesquiterpenes (25.5 %) dominated in the oil of T. polium with t-cadinol (18.3 %), germacrene D (15.3 %) and β-pinene (10.5 %) as predominant compounds; while monoterpenes (51.3 %) and oxygenated monoterpenes (45.2 %) were the most prominent groups in O. floribundum oil characterized by thymol (33.6 %), γ-terpinene (19.9 %) and p-cymene (15.5 %). The ethanol extracts were analyzed in terms of the dosage in total phenolic and flavonoids contents. Gallic acid equivalent representing total phenolic constituents of the extracts of T. polium and O. floribundum were 175 and 250 mg GAE/g, respectively; and quercetin equivalent representing total flavonoids were 29.5 and 180 mg QE/g, respectively. The antioxidant potential of the samples was evaluated using two separate methods, inhibition of free radical 2,2-diphenyl-1-picrylhydrazyl (DPPH) and reducing power. O. floribundum extract was the most able to reduce DPPH (IC 50= 18.5±0.1 µg/ml). Both plant oils were able to inhibit the 5-lipoxygenase (IC50= 125.7±7.3 µg/ml for Origanum and 482.52±0.73 µg/ml for T. polium. The antimicrobial activity of the oils and Origanum extract by the disc diffusion method against four bacteria and one fungus showed O.floribundum as being more active.