Isolation and identification of allelochemicals produced by Phaeodactylum tricornutum for Prorocentrum donghaiense

Diatom Phaeodactylum tricornutum was found to have a negative effect on the growth of Prorocentrum donghaiense, even induce cell apoptosis in our previous experiment. In this research, liquid-liquid extraction (LLE) and high performance liquid chromatography (HPLC) were used to extract and isolate allelochemicals from the filtrate of P. tricornutum. It was found that component XI could inhibit the growth of P. donghaiense significantly. The component XI was analyzed by Fourier transform infrared spectroscopy (FTIR) and gas chromatography mass spectrometry (GC-MS). The result showed that the extraction was a mixture of eight small molecule compounds with medium and low polarity. Most of these eight substances were synthetical, and only substance 6 (1-propene -1,2,3-tricarboxylic acid, tributyl ester) has been ever reported to have allelopathic activity. The experiment also verified the biological activity of substance 6. It was inferred from our results that substance 6 was an allelopathic substance secreted by P. tricornutum. Our research provides direct evidence to the existence of allelopathy between P. tricornutum and P. donghaiense.

Automated summary

In this study, allelochemicals were extracted and isolated from the filtrate of Phaeodactylum tricornutum, and it was found that these compounds had a significant inhibitory effect on the growth of Prorocentrum donghaiense. One specific compound, substance 6, was identified as having allelopathic activity, providing direct evidence of allelopathy between P. tricornutum and P. donghaiense.