Palytoxin and Analogs: Biological and Ecological Effects

Abstract

Palytoxin (PTX) is a potent marine toxin that was originally found in soft corals from tropical areas of the Pacific Ocean. Soon after, its occurrence was observed in numerous other marine organisms from the same ecological region. More recently, several analogs of PTX were discovered, remarkably all from species of the dinoflagellate genus Ostreopsis. Since these dinoflagellates are also found in other tropical and even in temperate regions, the formerly unsuspected broad distribution of these toxins was revealed. Toxicological studies with these compounds shows repeatedly low LD50 values in different mammals, revealing an acute toxic effect on several organs, as demonstrated by different routes of exposure. Bioassays tested for some marine invertebrates and evidences from environmental populations exposed to the toxins also give indications of the high impact that these compounds may have on natural food webs. The recognition of its wide distribution coupled with the poisoning effects that these toxins can have on animals and especially on humans have concerned the scientific community. In this paper, we review the current knowledge on the effects of PTX and its analogs on different organisms, exposing the impact that these toxins may have in coastal ecosystems.

Warm Seawater Microalgae: Growth and Toxic Profile of Ostreopsis Spp. from European Coasts

“…It was described that only the Japanese O. siamensis produces ostreocin [34], however other studies demonstrate that also Mediterranean O. siamensis synthesizes this toxin [13,35,36]. In addition PLTX or putative PLTX (depending on the author) have been identified in this specie [4,37,38].…”

“…Although the term PLTX-like compound is used to designate toxins coming from Ostreopsis spp. [13]. This controversy could be due to the lack of standards that prevent the clarification of the toxins produced by each strain.…”

“…One lower concentration than those that produce 0% of mouse death and one higher concentration than those that produce 100% of mouse death were also tested in Ostreopsis strains but only three mice were used in each case with the same result than previous concentration. Controls with different methanol percentage and matrix effect were done (three mice per condition) and no effects were observed of toxin potency proposed in the bibliography was PLTX>ostreocin-d>mascarenotoxin-a, and ovatoxin-a was not classified [13,47]. Taking into account our results and based on this classification, if ostreocin-d is present in O. siamensis, the compound produced by O. ovata A, probably ovatoxin-a, is more toxic and shows higher affinity by the Na,K-ATPase as FP results shows.…”

“…Different molecules related with the PLYX structure ( Figure 1) have been described: palytoxin-b, homopalytoxin, bishomopalytoxin, neopalytoxin, deoxypalytoxin, 42-hydroxypalytoxin, ostreocin-d, ovatoxin-a, -b,-c,-d, -e and -f and mascarenotoxin-a, -b and -c. However only the chemical structures of PLTX, ostreocin-d, ovatoxin-a and 42-hydroxypalytoxin have been characterized [4][5][6][7][8][9][10][11]. PLTX is a large molecule, with a molecular weight of 2659-2680 daltons depending on the origin [12,13].…”

Expedient nonclassical reaction of acetylenes with ketones: controlling the switch between bicyclic ketals and cyclopentenols formation

“…These are in temperature-, concentration-and solvent-dependent dynamic equilibrium, thus mimicking a kind of living system. 23 We have recently shown that the one-pot assembly of 3-methyl-7-methylene-1,5-diphenyl-6,8-dioxabicyclo[3.2.1]octane (having the pheromone frontaline scaffold) [24][25][26][27] from acetophenone 1a and acetylene 2a promoted by a KOH/DMSO suspension (Scheme 1) is accompanied by the formation of a minor product (yield < 1%), 3-benzoyl-2,4-dimethyl-1-phenyl-2-cyclopenten-1-ol (4a), a structural isomer of the bicyclic ketal 3a.…”