Investigation of the antibacterial activity of 3-O-octanoyl-(-)-epicatechin

• Published in: Journal of applied microbiology Vol. 105; no. 5; pp. 1461 - 1469
• Main Authors: Cushnie, T.P.T, Taylor, P.W, Nagaoka, Y, Uesato, S, Hara, Y, Lamb, A.J
• Format: Journal Article
• Language: English
• Published: Oxford, UK Oxford, UK : Blackwell Publishing Ltd 01.11.2008; Blackwell Publishing Ltd; Blackwell Science
• Subjects: Anti-Bacterial Agents - pharmacology; antibacterial; bactericidal; Biological and medical sciences; catechin; Catechin - analogs & derivatives; Catechin - pharmacology; Cell Aggregation - drug effects; cytoplasmic membrane; Drug Resistance, Bacterial - physiology; Enterococcus - cytology; Enterococcus - drug effects; flavan-3-ol; flavonoid; Flavonoids - pharmacology; Fundamental and applied biological sciences. Psychology; Microbial Sensitivity Tests; Microbiology; octanoyl; Staphylococcus aureus; Staphylococcus aureus - cytology; Staphylococcus aureus - drug effects; Catechin; Applied microbiology; cytoplasmic membrane; Membrane; antibacterial; flavan-3-ol; Antibacterial agent; Flavonoid; bactericidal; octanoyl; Bactericidal effect
• ISSN: 1364-5072; 1365-2672
• DOI: 10.1111/j.1365-2672.2008.03881.x

To measure antibacterial activity of the semi-synthetic flavonoid 3-O-octanoyl-(-)-epicatechin and investigate the mechanism of action. MICs determined by the broth microdilution method were 50 μg ml⁻¹ for β-lactam sensitive and resistant Staphylococcus aureus, and 100 μg ml⁻¹ for vancomycin sensitive and resistant enterococci. In time-kill studies, 100 μg ml⁻¹ 3-O-octanoyl-(-)-epicatechin reduced colony forming unit numbers of antibiotic sensitive and methicillin-resistant Staph. aureus below detectable levels within 120 min. Bacterial aggregation was not observed when cells exposed to 3-O-octanoyl-(-)-epicatechin were examined by light microscopy. It was also shown that 50 μg ml⁻¹ 3-O-octanoyl-(-)-epicatechin is capable of reducing colony forming unit numbers of high cell density Staph. aureus populations by 80-fold within 60 min incubation, and inducing leakage of 50% of their internal potassium within just 10 min. 3-O-Octanoyl-(-)-epicatechin is active against Gram-positive bacteria, has bactericidal activity against both antibiotic sensitive and resistant strains, and is likely to exert its primary antibacterial effect by damaging the cytoplasmic membrane. 3-O-Octanoyl-(-)-epicatechin has significant antibacterial activity and additional structural modification and/or formulation studies may allow this to be potentiated.