Amphidinin G, a putative biosynthetic precursor of amphidinin A from marine dinoflagellate Amphidinium sp.

Abstract A new linear polyketide, amphidinin G ( 1 ), has been isolated from a symbiotic marine dinoflagellate Amphidinium sp. The planar structure of 1 was established mainly based on the 2D NMR data and the stereochemistry was elucidated by the combination of J -value analysis, modified Mosher’s method, and NMR chemical shift comparison with synthetic analogues. Amphidinin G ( 1 ) was expected to be a biosynthetic precursor of amphidinin A ( 2 ), a known linear dinoflagellate polyketide. Amphidinin G ( 1 ) showed antifungal activity against Trichophyton mentagrophytes .