Allelochemicals produced by Skeletonema costatum were purified and characterized using various extraction, chromatographic, and mass spectrometric methods. The retentate fraction obtained from solid-phase extraction (SPE), as well as the original filtrate of S. costatum, greatly inhibited growth of Heterosigma akashiwo, while the permeate fraction promoted growth of H. akashiwo. The SPE retentate was further fractionated by liquid-liquid extraction, and the resulting chloroform fraction strongly inhibited the growth of H. akashiwo. The chloroform fraction was further separated into T1 (Rf value: 0.47) and T2 (Rf value: 0.60) fractions by thin-layer chromatography; both fractions inhibited growth of H. akashiwo, but the inhibitory effect of T2 was greater than that of T1. The T2 fraction was then subjected to reversed-phase high performance liquid chromatography (RP-HPLC). Six fractions (F-1 to F-6) were collected, based on the UV-monitored (235 nm) elution profile. Only F-4 and F-5 exhibited allelopathic effects on H. akashiwo, and the inhibitory effect of F-4 was greater than that of F-5. The F-4 fraction also had a strong autoinhibitory effect on the growth of S. costatum. Results of electrospray ionization-mass spectrometry (ESI-MS) suggested that the F-4 fraction contained at least two allelochemicals (m/z 268 and 514).
|Translated title of the contribution||Low molecular weight allelochemicals produced by the diatom, Skeletonema costatum|
|Number of pages||9|
|Publication status||Published - Jan 1 2012|
All Science Journal Classification (ASJC) codes
- Aquatic Science