Antimicrobial effect by extracts of rhizome of Alpinia officinarum Hance may relate to its inhibition of beta-ketoacyl-ACP reductase.
Inhibitory effects on bacterial growth showed that 40% ethanol extract of galangal (rhizome of Alpinia officinarum Hance) can inhibit Staphylococcus aureus, alpha-Hemolytic streptococcus, beta-Hemolytic streptococcus and Streptococcus pneumoniae. beta-ketoacyl-ACP reductase (FabG, EC.1.1.1.100) is a key enzyme in type II fatty acid synthase system in bacteria and catalyzes beta-ketoacyl-ACP reduction. The galangal extracts inhibited FabG with an IC(50) value of only 4.47 +/- 0.10 microg/mL and is more potent than other previously published inhibitors. Kinetics studies showed that the inhibition consisted of both reversible and irreversible inhibition. The extracts of galangal inhibit FabG in a competitive pattern against NADPH. So far, no inhibitor has been reported to exhibit irreversible inhibition of FabG, whereas the galangal ethanol extract can inhibit FabG irreversibly. The irreversible inhibition presented two phases. It is probable that the galangal extract inhibit FabG, thereby displaying antibacterial ability.
Huang
Hui
H
College of Life Sciences, Graduate University of Chinese Academy of Sciences, Beijing, P. R. China.
Wu
Dan
D
Tian
Wei-Xi
WX
Ma
Xiao-Feng
XF
Wu
Xiao-Dong
XD
D064431:3-Oxoacyl-(Acyl-Carrier-Protein) Reductase; D000429:Alcohol Oxidoreductases / Q000037:antagonists & inhibitors*; D032429:Alpinia / Q000737:chemistry*; D000900:Anti-Bacterial Agents / Q000737:chemistry* / Q000494:pharmacology; D004791:Enzyme Inhibitors; D020128:Inhibitory Concentration 50; D008826:Microbial Sensitivity Tests; D010936:Plant Extracts / Q000737:chemistry / Q000494:pharmacology*; D027343:Rhizome / Q000737:chemistry; D013291:Streptococcus / Q000187:drug effects* / Q000201:enzymology
D000900:Anti-Bacterial Agents; D004791:Enzyme Inhibitors; D010936:Plant Extracts; D000429:Alcohol Oxidoreductases; D064431:3-Oxoacyl-(Acyl-Carrier-Protein) Reductase