Fig. 2. Observed HMBC correlations for 1–2 in Biofilm blocking sesquiterpenes from Teucrium polium

Fig. 2. Observed HMBC correlations for 1–2 as indicated by the arrows.Published as part of <i>Elmasri, Wael A., Hegazy, Mohamed-Elamir F., Aziz, Mina, Koksal, Ekrem, Amor, Wail, Mechref, Yehia, Hamood, Abdul N., Cordes, David B. & Paré, Paul W., 2014, Biofilm blocking sesquiterpenes from Teucrium polium, pp. 107-113 in Phytochemistry 103</i> on page 109, DOI: 10.1016/j.phytochem.2014.03.029, <a href="http://zenodo.org/record/10489548">http://zenodo.org/record/10489548</a&gt

Biofilm blocking sesquiterpenes from <em>Teucrium polium</em>

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 4 beta,5 alpha-epoxy-7 alpha H-germacr-10(14)-en-6 beta-ol-1-one, 4 beta,5 alpha-epoxy-7 alpha H-germacr-10(14)-en,1 beta-hydroperoxy1,6 beta-ol, 4 beta,5 alpha-epoxy-7 alpha H-germacr-10(14)-en,1 beta-hydroperoxy1,6 beta-ol and 4 beta,5 alpha-epoxy-7 alpha H-germacr-10(14)-en,1 beta-hydroperoxyl,6 alpha-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, H-1 and C-13 NMR) data, as well as two-dimensional NMR (H-1-H-1 COSY, HMQC, NOESY and HMBC), and ESI-MS analysis. The relative stereochemistiy 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 mu Mol range. Diverse sesquiterpene-skeleton structure and corresponding comprehensive enzyme capacity is discussed. </i

Biofilm blocking sesquiterpenes from <em>Teucrium polium</em>

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 4 beta,5 alpha-epoxy-7 alpha H-germacr-10(14)-en-6 beta-ol-1-one, 4 beta,5 alpha-epoxy-7 alpha H-germacr-10(14)-en,1 beta-hydroperoxy1,6 beta-ol, 4 beta,5 alpha-epoxy-7 alpha H-germacr-10(14)-en,1 beta-hydroperoxy1,6 beta-ol and 4 beta,5 alpha-epoxy-7 alpha H-germacr-10(14)-en,1 beta-hydroperoxyl,6 alpha-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, H-1 and C-13 NMR) data, as well as two-dimensional NMR (H-1-H-1 COSY, HMQC, NOESY and HMBC), and ESI-MS analysis. The relative stereochemistiy 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 mu Mol range. Diverse sesquiterpene-skeleton structure and corresponding comprehensive enzyme capacity is discussed. </i

Multitargeted Flavonoid Inhibition of the Pathogenic Bacterium <i>Staphylococcus aureus</i>: A Proteomic Characterization

Growth inhibition of the pathogen Staphylococcus aureus with currently available antibiotics is problematic in part due to bacterial biofilm protection. Although recently characterized natural products, including 3′,4′,5-trihydroxy-6,7-dimethoxy-flavone [<b>1</b>], 3′,4′,5,6,7-pentahydroxy-flavone [<b>2</b>], and 5-hydroxy-4′,7-dimethoxy-flavone [<b>3</b>], exhibit both antibiotic and biofilm inhibitory activities, the mode of action of such hydroxylated flavonoids with respect to S. aureus inhibition is yet to be characterized. Enzymatic digestion and high-resolution MS analysis of differentially expressed proteins from S. aureus with and without exposure to antibiotic flavonoids (<b>1</b>–<b>3</b>) allowed for the characterization of global protein alterations induced by metabolite treatment. A total of 56, 92, and 110 proteins were differentially expressed with bacterial exposure to <b>1</b>, <b>2</b>, or <b>3</b>, respectively. The connectivity of the identified proteins was characterized using a search tool for the retrieval of interacting genes/proteins (STRING) with multitargeted S. aureus inhibition of energy metabolism and biosynthesis by the assayed flavonoids. Identifying the mode of action of natural products as antibacterial agents is expected to provide insight into the potential use of flavonoids alone or in combination with known therapeutic agents to effectively control S. aureus infection