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In vitro Antimicrobial Activity of Royleanone Derivatives Against Gram-Positive Bacterial Pathogens

Authors

  • Patrícia Rijo,

    1. Faculdade de Farmácia da Universidade de Lisboa, Research Institute of Medicines and Pharmaceutical Sciences – iMed.UL, Lisboa, Portugal
    2. CBios – Research Center for Health Sciences & Technologies (Lab. Pharmacology and Therapeutics), Universidade Lusófona, Lisboa, Portugal
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  • Aida Duarte,

    1. Faculdade de Farmácia da Universidade de Lisboa, Research Institute of Medicines and Pharmaceutical Sciences – iMed.UL, Lisboa, Portugal
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  • Ana Paula Francisco,

    1. Faculdade de Farmácia da Universidade de Lisboa, Research Institute of Medicines and Pharmaceutical Sciences – iMed.UL, Lisboa, Portugal
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  • Teresa Semedo-Lemsaddek,

    1. Faculdade de Medicina Veterinária, Centro de Investigação Interdisciplinar em Sanidade Animal, Universidade Técnica de Lisboa, Lisboa, Portugal
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  • Maria Fátima Simões

    Corresponding author
    1. Faculdade de Farmácia da Universidade de Lisboa, Research Institute of Medicines and Pharmaceutical Sciences – iMed.UL, Lisboa, Portugal
    • Correspondence to: Maria Fátima Simões, Faculdade de Farmácia da Universidade de Lisboa, Research Institute of Medicines and Pharmaceutical Sciences, iMed.UL, Av. Prof. Gama Pinto, 1649-003 Lisboa, Portugal.

      E-mail: fasimoes@ff.ul.pt

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Abstract

Infections caused by multiresistant bacterial pathogens are a significant problem worldwide, turning the search for natural compounds to act as alternatives to antibiotics of major importance. The aim of the present study was to investigate the in vitro antimicrobial activity of 7α-acetoxy-6β-hydroxyroyleanone (1), isolated from Plectranthus grandidentatus (Lamiaceae), and 11 additional royleanone abietane derivatives of 1 (2–12) against important Gram-positive human bacterial pathogens. Results showed that the aromatic and alkylic esters 2, 3 and 5 are more active than 1 against Enterococcus and Staphylococcus (minimum inhibitory concentration (MIC) values ranging from 0.98 to 62.50 µg/mL). Moreover, 7α-acetoxy-6β-hydroxy-12-O-(4-chloro)benzoylroyleanone (2) gave rise to a new antibacterial-prototype (MIC values of 3.91–15.63 µg/mL against Staphylococcus and of 0.98–3.91 µg/mL against Enterococcus). The results showed that the compounds under analysis also present antimicrobial activity against resistant bacteria. The hydrophobic extra-interactions with bacterial targets seem to play an important role on the activity of royleanones derivatives. Copyright © 2013 John Wiley & Sons, Ltd.

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