RESUMO
Teucrium atratum Pomel. is a species belonging to the Lamiaceae family used in Algerian folk medicine. The present work essentially aimed to assess the phenolic composition and to evaluate some of the biological effects of different extracts, never previously studied, of T. atratum growing in Algeria. High levels of total phenolic and flavonoids were recorded in the hydromethanolic extract. Chlorogenic acid, isoquercetin, coumarin, cinnamic acid, quercetin dihydrate, and catechin were identified in the methanolic extract by mean of HPLC. The antioxidant activity assessed showed that the methanolic extract was the most active, while, the hydromethanolic extract showed a great power to reduce iron. In addition, all extracts had a significant antibacterial effect against the four tested bacterial strains, with Staphylococcus aureus as the most sensitive one. These findings can be a starting point to evaluate the plant as a source of natural bioactive compounds with antioxidant and antibacterial effects.
RESUMO
The aerial parts of Centaurea pullata afforded, in addition to the previously isolated sesquiterpene lactones, 11beta,13-dihydrocnicin and 11beta,13-dihydro-19-desoxycnicin, three minor sesquiterpene lactones, namely, a new germacranolide, 8alpha-O-(4-acetoxy-5-hydroxyangeloyl)-11beta,13-dihydrocnicin, and two new eudesmanolides, 8alpha-O-(4-hydroxy-2-methylenebutanoyloxy)-11beta,13-dihydrosonchucarpolide and 8alpha-O-(4-hydroxy-2-methylenebutanoyloxy)-11beta,13-dihydro-4-epi-sonchucarpolide. The in vitro antimicrobial activity of all isolated sesquiterpene lactones was tested against six bacteria and eight fungal species, using a microdilution method. All compounds tested showed greater antibacterial and antifungal activities than the positive controls used.
