Biofilm blocking sesquiterpenes from Teucrium polium

• Published in: Phytochemistry (Oxford) 2014-07, Vol.103, p.107-113
• Main Authors: Elmasri, Wael A., Hegazy, Mohamed-Elamir F., Aziz, Mina, Koksal, Ekrem, Amor, Wail, Mechref, Yehia, Hamood, Abdul N., Cordes, David B., Paré, Paul W.
• Format: Article
• Language: English
• Subjects: Anti-Bacterial Agents - chemistry; Anti-Bacterial Agents - pharmacology; Biofilm blocking; Biofilms - drug effects; Lamiaceae; Magnetic Resonance Spectroscopy; Molecular Structure; Sesquiterpenes; Sesquiterpenes - chemistry; Sesquiterpenes - pharmacology; Staphylococcus aureus - drug effects; Teucrium - chemistry; Teucrium polium
• ISSN: 0031-9422; 1873-3700
• DOI: 10.1016/j.phytochem.2014.03.029

Chemical investigations of the aerial parts of T. polium yielded four sesequiterpenes (1–4), in addition to 12 previously identified compounds. All compounds were assessed for anti-biofilm activity. [Display omitted] •Teucrium polium stems/leaves were MeOH/CH2Cl2 extracted.•Compounds 1–4, in addition to twelve previously reported metabolites, were found.•Structures were established by spectroscopic methods, including MS and NMR analysis.•Staphylococcus aureus anti-biofilm activity in the low μMol range was observed.•Diverse sesquiterpene-skeleton structure/comprehensive enzyme capacity is proposed. The chemical composition and antibacterial activity of Teucrium polium L. (Lamiaceae) were assessed; sixteen compounds were isolated from a CH2Cl2/MeOH extract of the aerial parts of the plant including four sesquiterpenes 4β,5α-epoxy-7αH-germacr-10(14)-en-6β-ol-1-one, 4β,5α-epoxy-7αH-germacr-10(14)-en,1β-hydroperoxyl,6β-ol, 4β,5β-epoxy-7αH-germacr-10(14)-en,1β-hydroperoxyl,6β-ol and 4α,5β-epoxy-7αH-germacr-10(14)-en,1β-hydroperoxyl,6α-ol, together with seven known sesquiterpenes, one known iridoid glycoside, two known flavonoids, and one known phenylpropanoid glycoside. Structures were elucidated on the basis of spectroscopic (UV, 1H and 13C NMR) data, as well as two-dimensional NMR (1H–1H COSY, HMQC, NOESY and HMBC), and ESI-MS analysis. The relative stereochemistry of the ketone was established by X-ray crystallography, while its absolute configuration was attained by a modified Mosher’s method. Antibacterial activity of the crude extract, as well as with four of the isolated metabolites, was observed with Staphylococcus aureus anti-biofilm activity in the low μMol range. Diverse sesquiterpene-skeleton structure and corresponding comprehensive enzyme capacity is discussed.