Presence of benzoate-type toxins in Gymnodinium catenatum Graham isolated from the Mexican Pacific

Abstract

Benzoate type toxins have been described as an important component of Gymnodinium catenatum cells. In this paper we study these toxins in a G. catenatum strain isolated from the Mexican coast. A partition of the toxins was done by solid-phase extraction on a COOH cartridge and detected by HPLC coupled to fluorescence after pre-column periodate oxidation. Two groups of the hydrophobic analogues of saxitoxin were identified: those containing a sulphate group in the benzoate moiety instead of a hydroxyl group like GC1/2 or GC3 and the hydroxy-benzoate analogues, with a sulphate group at the eleventh position of the STX core present or absent (GCs-GTX and GCs-STX analogues, respectively). These toxins are more abundant, in a relative basis, when comparing with a G. catenatum toxin content isolated from Portugal. This is the first report of the presence of these toxins in a Mexican strain.