Antibiofilm Activity of Galangal (Alpinia galanga) Against Staphylococcus aureus

Abstract

A significant antibacterial effect of Galangal (Alpinia galangal) against foodborne bacteria Staphylococcus aureus, and Listeria monocytogenes, was reported with higher quantity of active biomolecule 1’-acetoxychavicolacetate. However, the effect on biofilm formation is yet unknown. Therefore, crude extract of Galangal rhizome was investigated for in-vitro antibiofilm activity against Staphylococcus aureus. Galangal extract was tested for antimicrobial activity against six strains of S. aureus including methicillin resisitant S. aureus. The antibiofilm activity was tested against S. aureus SA113 using microtiter-plate assay and scanning electron microscopic imaging. Galangal extract showed antimicrobial activity with an inhibition zone ranging from 36 - 46 mm against for all tested strains of S. aureus. The minimum inhibitory concentration and the minimum bactericidal concentration of the extract were 1.25 mg/ml and 5 mg/ml, respectively. More than 50% reduction of biofilm adhered to the surface was observed in 2.5 mg/ml representing minimum biofilm resistant concentration MBRC50 of the extract. The antibiofilm assay showed significant (80.68%) reduction at 20 mg/ml of extract. The 1´acetochavicol acetate (82.88%) was found to be the major chemical compound of galangal extract. Galangal rhizome extract possesses antibiofilm activity against S. aureus. Findings of the study could be useful for application of galangal crude extract as a disinfectant in food industry to eliminate the cross contaminations of S. aureus.