Solid-phase extraction clean-up of ciguatoxin-contaminated coral fish extracts for use in the mouse bioassay

Chun-Kwan Wong (1)

1 Dept of Health

Florisil solid-phase extraction (SPE) cartridges were used for purifying ciguatoxin-contaminated (CTX-contaminated) coral fish extracts, with an aim to removing extracted lipid but retaining optimal level of CTXs in the purified fractions. CTX-containing fraction (target fraction) in fish ether extract was isolated and purified by eluting through a commercially available Florisil cartridge with hexane-acetone-methanol solvent mixtures of increasing polarity (hexane-acetone (4:1, v:v) < acetone-methanol (7:3, v:v) < 100% methanol). Application of Florisil SPE using acetone-methanol (7:3, v:v) condition facilitated the separation of 4.2„b0.4 mg (mean„bS.E.M.) of purified target fraction from 20 mg ether extract with good retention of CTXs. Mouse bioassay analysis demonstrated that the average CTX recovery of target fraction from CTX-spiked samples was 75.8„b3.3%, which was significantly increased by 96.7„b15% when compared with CTX recovery from ether extracts (44.8„b5.2%) without performing SPE purification. Over 70% of non-target lipids were removed, in which no CTX toxicity was found. Moreover, the target fractions of both CTX-spiked and naturally CTX-contaminated samples elicited more prominent toxic responses of hypothermia and/or induced more rapid death of the mice. The use of acetone-methanol (7:3, v:v) condition in the elution could significantly improve overall recovery of CTXs, while minimizing the possible interferences of lipidic matrix from co-extractants on mice.

Mots clés: Life Sciences

Chun-Kwan Wong. Solid-phase extraction clean-up of ciguatoxin-contaminated coral fish extracts for use in the mouse bioassay. Food Additives and Contaminants, 2009, 26 (02), pp.236-247. ⟨10.1080/02652030802342505⟩. ⟨hal-00577325⟩