Cylindrospermopsins

Cylindrospermopsins are a family of cyanobacterial alkaloid toxins produced by freshwater cyanobacteria, most notably Cylindrospermopsis raciborskii and Aphanizomenon ovalisporum, with occasional reports from other genera. They are hepatotoxins and cytotoxins that can damage the liver and kidneys in humans and animals, and have been associated with waterborne outbreaks during cyanobacterial blooms.

Chemically, cylindrospermopsins are nitrogen-containing alkaloids with a distinctive tricyclic framework that includes a guanidine moiety and a uracil-like component. They are produced by cyanobacterial gene clusters (often referred to as cyr) and their production is influenced by environmental conditions such as temperature, nutrient status, and bloom dynamics.

Occurrence and exposure: Cylindrospermopsins have been detected in freshwater systems worldwide where blooms occur. They can be released into water during cell lysis and may enter drinking water supplies or recreational waters, posing a risk to humans, livestock, and wildlife, particularly during or after blooms.

Health effects and regulation: Acute exposure may cause gastrointestinal symptoms and liver injury; higher exposures have caused hepatotoxicity in humans and animals. Because of potential health risks, many countries monitor cylindrospermopsin levels in surface water and provide advisories or treatment guidelines for affected water bodies. Risk assessment often addresses co-occurring cyanotoxins such as microcystins.

Detection and treatment: Analytical methods such as LC-MS/MS and immunoassays are used to detect cylindrospermopsin in water and biological samples. Water treatment strategies—including source water protection, oxidation, and advanced treatment processes—are employed to reduce concentrations in drinking water.