Hepatotoxic products of cyanobacteria and their toxicological effects

Abstract

Chronic human exposure to water contaminated with hepatotoxic cyanobacterial compounds (cyanotoxins) can lead to an increased incidence of hepatocellular carcinoma or other forms of liver disease. Humans can be exposed to cyanotoxins through ingestion, inhalation and dermal contact, i.e. by using contaminated drinking water, recreational water, water used for hemodialysis or via food. Among hepatotoxic cyanotoxins, cyclic peptides microcystins and nodularin should be emphasized, as well as the tricyclic alkaloid cylindrospermopsin. In addition, the existence of a new hepatotoxic cyanobacterial secondary metabolite, called limnotrixin, has been investigated in recent years. Due to the different chemical structures of these cyanotoxins, mechanisms of their toxic effects also differ. Globally, hepatotoxins are the most common cyanobacterial toxins and, among them, microcystins are the most frequently detected during cyanobacterial blooms and also the most extensively studied. The latter is also the case in the Republic of Serbia, where cases of cyanobacterial blooms in water bodies used for water supply are mostly related to species that are potential microcystin producers (e.g. representatives of the genera Microcystis and Planktothrix). Additionally, microcystins are the only group of hepatotoxic cyanotoxins for which regular monitoring has been established in our country, which primarily refers to the water bodies used as water supply sources. However, since there is an increased frequency of cyanobacterial blooming, both worldwide and in our country, it is very important to monitor potential risks and understand the toxicity and potential carcinogenicity of hepatotoxic products of cyanobacteria, which was the main aim of this study