An extract from teak (Tectona grandis) bark inhibited Listeria monocytogenes and methicillin resistant Staphylococcus aureus.

AIMS The aim of this study was to characterize the inhibitory mechanism in teak (Tectona grandis) bark and to determine its effectiveness against Listeria monocytogenes and methicillin resistant Staphylococcus aureus (MRSA). METHODS AND RESULTS Methanol extracts of teak bark were inhibitory to L. monocytogenes and MRSA by means of disc diffusion. Gas chromatography-mass spectrometry, and (1)H and (13)C nuclear mass resonance analyses revealed that the inhibitory compound had a molecular weight of 174, and a structure of 5-hydroxy-1,4-naphthalenedione (Juglone). CONCLUSIONS 5-hydroxy-1,4-naphthalenedione (Juglone) inhibited L. monocytogenes and MRSA. SIGNIFICANCE AND IMPACT OF THE STUDY A compound in an extract of teak bark was inhibitory to L. monocytogenes and MRSA.