Investigation of the antibacterial activity of 3-O-octanoyl-(-)-epicatechin.
OBJECTIVE
To measure antibacterial activity of the semi-synthetic flavonoid 3-O-octanoyl-(-)-epicatechin and investigate the mechanism of action.


RESULTS
MICs determined by the broth microdilution method were 50 microg ml(-1) for beta-lactam sensitive and resistant Staphylococcus aureus, and 100 microg ml(-1) for vancomycin sensitive and resistant enterococci. In time-kill studies, 100 microg 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 microg 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.


CONCLUSIONS
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.


CONCLUSIONS
3-O-Octanoyl-(-)-epicatechin has significant antibacterial activity and additional structural modification and/or formulation studies may allow this to be potentiated.
Cushnie
T P T
TP
School of Pharmacy, The Robert Gordon University, Schoolhill, Aberdeen, UK.
Taylor
P W
PW
Nagaoka
Y
Y
Uesato
S
S
Hara
Y
Y
Lamb
A J
AJ
D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D002392:Catechin / Q000031:analogs & derivatives* / Q000494:pharmacology; D002449:Cell Aggregation / Q000187:drug effects; D024881:Drug Resistance, Bacterial / Q000502:physiology; D016983:Enterococcus / Q000166:cytology / Q000187:drug effects*; D005419:Flavonoids / Q000494:pharmacology*; D008826:Microbial Sensitivity Tests; D013211:Staphylococcus aureus / Q000166:cytology / Q000187:drug effects*
C499927:3-O-octanoyl-catechin; D000900:Anti-Bacterial Agents; D005419:Flavonoids; D002392:Catechin