Palytoxin

Palytoxin, PTX or PLTX is an intense vasoconstrictor, and is considered to be one of the most poisonous non-protein substances known, second only to maitotoxin in terms of toxicity in mice. Palytoxin is a polyhydroxylated and partially unsaturated compound (8 double bonds) with a long carbon chain. It has water-soluble and fat-soluble parts, 40 hydroxy groups and 64 chiral centers. Due to chirality and possible double bond cis-trans isomerism, it has over 1021 alternative stereoisomers. It is thermostable, and boiling contaminated seafood does not noticeably reduce toxicity. It remains stable in aqueous solutions for prolonged periods but rapidly decomposes in acidic or alkaline solutions. It has multiple analogues such as ostreocin-D, mascarenotoxin-A and -B. Palytoxin occurs at least in tropics and subtropics where it is made by Palythoa corals and Ostreopsis dinoflagellates, or possibly by bacteria occurring in these organisms. It can be found in many more species like fish and crabs due to the process of biomagnification. It can also be found in various sponges, mussels, starfish and cnidaria. People are rarely exposed to palytoxin. Exposures have happened in people who have eaten contaminated fish and crabs, but also in aquarium hobbyists who have handled Palythoa corals incorrectly and in those who have been exposed to certain algal blooms. Palytoxin targets the sodium-potassium pump protein by locking it into a position where it allows passive transport of both sodium and potassium ions, thereby destroying the ion gradient that is essential for life. As palytoxin can affect every type of cell in the body, the symptoms can be very different for the various routes of exposure. Palytoxin's chemical structure was solved in 1981 by two research groups independently from each other. Stereochemistry was solved in 1982. Palytoxin carboxylic acid was synthesized by Yoshito Kishi and colleagues in 1989 and actual...