Marine Biotoxins

Overview

Marine biotoxins are mainly produced by algae, phytoplankton or microorganisms. They can exist in shellfish, fish and other Marine organisms for a long time and have heat resistance. Therefore, conventional processing methods such as heating and microwave cannot inactivate them. When it enters the human body through the food chain, it is easy to produce toxic side effects on the liver, cells, cardiovascular system and nervous system, thus causing human poisoning. In recent years, Marine toxins have become the most rapidly developed field in the study of Marine bioactive substances due to the problems of food safety, ecological safety and public safety.

Types of marine biotoxins

• Paralytic Shellfish Poisoning (PSP)

Saxitoxin (STX) is a kind of toxin accumulated in the body after Alexandrium sp. and Gymnodinium sp. filtered by the saxidomus giganteus. It produces paralytic poisoning effect after poisoning, also known as paralytic shellfish toxin, which is a class of amino phthaloid toxin. Saxitoxin acts on sodium ion channels, making nerve conduction difficult, paralyzing the central and peripheral nervous systems, and causing death in humans or animals due to respiratory failure.

• Diarrhetic Shellfish Poisoning (DSP)

Okadaic acid (OA) was first isolated from Halichondria okadai in 1981 and later from H. Melonodocia. OA is a tumor promoter. It also inhibits calcium-activated phospholipid-dependent protein kinases, is an inhibitor of protein phosphatase 1, 2A, and 2B, and can be used as a tool for studying cell regulation.

• Tetrodotoxin (TTX)

TTX can be derived from a variety of Marine and even terrestrial animals, and may initially be synthesized by symbiotic microorganisms in venomous organisms. TTX is highly toxic, with an LD₅₀ of 8.7μg/kg. At very low concentrations, TTX can selectively inhibit the passage of Na⁺ ions and allow the passage of K⁺ ions. Clinically, it is used to treat various neuromuscular pain, trauma and spasm.

• Azaspiracid Shellfish Poisoning (AZP)

AZP is structurally distinct from other toxins in that it is a nitrogenous polyether containing spirals and ends with carboxyl groups. The main symptoms of poisoning are nausea, vomiting, diarrhea and stomach cramps.

• Hepatotoxic Shellfish Poisoning (HSP)

Yessotoxin (YTXs) and Pectenotoxins (PTXs) are collectively called HSP, based on their hepatotoxic effects. PTXs is a class of polyether macrolides isolated from escallop. PTX2 has strong cytotoxic selective effect on human lung, rectum and breast cancer cells.

• Amnesic Shellfish Poisoning (ASP)

Domoic acid was first isolated from Chondria armata in Japan by the Japanese scholar Daigo et al. in 1958, and can be used as a tool to study neurodegenerative diseases.

• Neurotoxic Shellfish Poisoning (NSP)

Brevetoxins (BTX) are isolated from Ptychodiscus brevis, which produce red tides in the Gulf of Mexico. BTX can cause Na⁺ influx, which leads to depolarization of muscle and nerve cells.

• Ciguatoxin (CTX)

CTX comes mainly from Gynnothorax jauanicus. CTX is a novel sodium channel agonist with high selectivity on nervous system, digestive system, cardiovascular system and cell membrane.

Fig. 2 Classifications of Marine Based-Toxins. (Fatih Özogul.; et al. 2018)