Structures of the Largest Amphidinol Homologues from the Dinoflagellate Amphidinium carterae and Structure–Activity Relationships

Abstract

Amphidinols are polyketide metabolites produced by marine dinoflagellates and are chiefly composed of a long linear chain with polyol groups and polyolefins. Two new homologues, amphidinols 20 (AM20, 1) and 21 (AM21, 2), were isolated from Amphidinium carterae collected in Korea. Their structures were elucidated by detailed NMR analyses as amphidinol 6-type compounds with remarkably long polyol chains. Amphidinol 21 (2) has the longest linear structure among the amphidinol homologues reported so far. The congeners, particularly amphidinol 21 (2), showed weaker activity in hemolysis and antifungal assays compared to known amphidinols.

LC-MS/MS Method Development for the Discovery and Identification of Amphidinols Produced by Amphidinium

“…Several AM adducts have been described in the literature: The sodium adduct (+Na + ) was used to identify AM-A [ 23 ], the hydrogen adduct (+H + ) for AM-20 [ 14 ], and ammonium adduct (+NH 4 + ) for AM-22 [ 16 ]. However, for a detection method that is both broadly applicable and allows for the comparison of ion intensities, it is highly advantageous to focus on one adduct form.…”

“…To avoid confusion, in this work the term “AM” includes all compound groups listed above. The majority of AM have been tested for a variety of biological activities, with antifungal and hemolytic effects observed in almost all investigated AM, i.e., [ 12 , 13 , 14 ]. In less frequent cases, cytotoxic and anticancer effects were also found [ 15 , 16 ].…”

Marine natural products

“…Culture of a strain of Amphidinium carterae collected in South Korea has yielded the polyketides amphidinol 20 838 and 21 839, with 839 possessing the longest linear structure reported in all isolated amphidinols to date. 326 An Italian strain of A. carterae was the source of two further amphidinols 840, 841 and investigations into the biosynthesis of 840 utilising 13 C labelled acetate and glycolate proved that glycolate is the starter unit for polyketide chain assembly in amphidinols. 327 A further strain of Amphidinium yielded 842, 843, 15-and 19-membered macrolides respectively.…”

Amphidinol 22, a New Cytotoxic and Antifungal Amphidinol from the Dinoflagellate Amphidinium carterae

“…Until now, various Amphidinium strains have displayed different biological activities and chemical diversity [17,18,19,20,21,22,23]. Various compounds have been isolated from these strains, including the amphidinols (AM), amphirionins, karatungiols and more than 45 cytotoxic macrolides, known as amphidinolides.…”