Abstract

The aim of this study was to explore the killing kinetics and bactericidal mechanism of action of A. galanga against food borne bacteria in order to promote this plant as a source of natural preservative. The comparison on antibacterial power was firstly done among its essential oil and the crude extracts obtained from various extracting solvents. The essential oil showed the extremely strongest antibacterial activity and more effective killing activity against Gram negative than Gram positive food borne bacteria. The kinetic time of the oil for complete bactericidal action against E. coli was 40 min whereas that of gentamicin was 120 min. The scanning electron microscopy (SEM) of bacterial morphology after exposed to the oil showed bacterial membrane destruction. It was concluded that the essential oil is the highest potential part of A. galanga against food borne bacteria. Its killing kinetics against Gram negative bacteria was extremely faster than a broad spectrum antibiotic gentamicin. Its mechanism of bactericidal action was along with the bacterial membrane disruption and malfunction leading to cell death.

Key words: Alpinia galanga, antibacterial, mechanism of action, essential oil, killing kinetics.