Oxidative transformation of a naturally occurring okadaic acid diol ester by the diatom Thalassiosira weissflogii

The diarrhetic shellfish poisoning (DSP) toxin okadaic acid (1) is found in extracts of the dinoflagellate Prorocentrum lima together with a suite of diol esters such as 2. When 2 was added to the culture medium of the centric diatom Thalassiosira weissflogii, it was transformed into a range of products within three days. Three of these products, 3, 4 and 5, were isolated from the medium and identified as oxidation products 2, suggesting that the diatom produces DSP metabolites of greater polarity as a means of detoxification. In addition, another diol ester product 6 was identified as a minor impurity of 2.Peer reviewed: YesNRC publication: Ye