In vitro antioxidant activity of some Teucrium species (Lamiaceae).

The chemical composition and antioxidant activity of different extracts (diethyl ether, ethyl acetate and n-butanol) obtained from Teucrium species (T. chamaedrys, T. montanum, T. polium) were investigated in this work. Phytochemical screening of the plant extracts proved the presence of flavonoids luteolin, apigenin and/or diosmetin. The chemical composition of extracts was evaluated by HPLC and spectrophotometry. Antioxidant activities of the extracts were evaluated using three complementary in vitro assays: inhibition of DPPH (1,1-diphenyl-2-picrylhydrazyl) radical, inhibition of hydroxyl radicals and protection of beta-carotene-linoleic acid model system. In the first two assays, strong inhibitory activity was shown by T. montanum and T. chamaedrys extracts. In the beta-carotene-linoleic acid model system, extracts from T. polium showed remarkable activity. These findings demonstrated that Teucrium species possess free radical and hydroxyl radical scavenging activity as well as antioxidant activity in vitro.