Withdrawn Paper: Antibacterial Effect of Five Zingiberaceae Essential Oils by Laohakunjit et al., Molecules 2007, 12, 2047- 2060

In a Letter to the Editor published last year [1] possible factual errors in the paper by Laohakunjit et al. [2] that is the subject of this Editor's Note were brought to our attention. In that paper the major component of the solvent extracts of essential oil of galanga (Alpinia galanga Sw.) was identified as fraesol (ethyl 3-methyl-3-phenylglycidate, 1). In [1] it was suggested that since fraesol is a well known synthetic compound, that exists as two optically active pairs of cis and trans isomers [3] and has never been isolated from a natural source, it was more likely that this component was either acetoxychavicol acetate (2), a reported major component of the essential oil of galanga rhizome [4] or ethyl trans-p-methoxycinnamate (3), which has a related structure and identical molecular weight as fraesol and has been previously identified in the essential oil of Kaempheria galangal L. [5]. Possible additional errors in the identification of other components were also mentioned.

In light of this new information Laohakunjit et al. were invited to submit a rebuttal to this Letter and/or a correction to their paper, if appropriate. Unfortunately, their initial response was altogether unsatisfactory and their proposed reassignments of GC peaks and component identities raised even more questions about the accuracy of claims published in [2]. Furthermore, during our investigation of this matter we also became aware of numerous papers concerning this same topic [6,7,8,9,10], that had not been cited by the authors.

Almost six months have now elapsed since this was communicated to the authors, who have failed to respond to our numerous e-mails requesting some action on this matter, so in consideration of the doubts about the validity of the contents of [2] and in the absence of any data supporting the authors' claims, as Editor-in-Chief of Molecules, I am regretfully declaring this paper withdrawn. The corresponding Table of Contents entry shall be linked to this note and the pages watermarked with the word "Withdrawn".