Fumonisins

Fumonisins

Fumonisins are a group of mycotoxins produced by several species of the genus *Fusarium*, primarily *Fusarium verticillioides* and *Fusarium proliferatum*. These toxins are commonly found in maize and maize-based products and pose significant health risks to both humans and animals. Fumonisins are known to cause a variety of diseases, including cancer and neural tube defects in humans, as well as equine leukoencephalomalacia and porcine pulmonary edema in animals.

Chemical Structure and Properties

Fumonisins are structurally related to sphingolipids, which are essential components of cell membranes. The most studied fumonisin is fumonisin B1 (FB1), which consists of a long-chain hydrocarbon backbone with two tricarballylic acid groups and an amino group. This structure allows fumonisins to interfere with sphingolipid metabolism, leading to the accumulation of toxic sphingoid bases.

Biosynthesis

Fumonisins are synthesized by the polyketide synthase pathway in *Fusarium* species. The biosynthetic gene cluster responsible for fumonisin production has been identified and includes genes encoding for polyketide synthases, cytochrome P450 monooxygenases, and other enzymes involved in the modification of the polyketide backbone.

Health Effects

Fumonisins have been associated with several adverse health effects:

In Humans

1. Cancer: Epidemiological studies have linked fumonisin exposure to an increased risk of esophageal cancer, particularly in regions where maize is a dietary staple. 2. Neural Tube Defects: Fumonisins have been implicated in the occurrence of neural tube defects in newborns, possibly due to their interference with folate metabolism.

In Animals

1. Equine Leukoencephalomalacia (ELEM): Horses consuming fumonisin-contaminated feed can develop ELEM, a neurological disorder characterized by liquefactive necrosis of the white matter in the brain. 2. Porcine Pulmonary Edema (PPE): Pigs exposed to fumonisins may suffer from PPE, a condition marked by fluid accumulation in the lungs and respiratory distress.

Detection and Regulation

The detection of fumonisins in food and feed is typically performed using chromatographic techniques such as high-performance liquid chromatography (HPLC) coupled with mass spectrometry (MS). Regulatory agencies, including the World Health Organization (WHO) and the Food and Agriculture Organization (FAO), have established maximum allowable levels of fumonisins in food and feed to minimize health risks.

Prevention and Control

Strategies to reduce fumonisin contamination include: 1. Good Agricultural Practices (GAP): Implementing GAP can help reduce the incidence of *Fusarium* infection in crops. 2. Biological Control: The use of non-toxigenic strains of *Fusarium* or other microorganisms can help outcompete toxigenic strains. 3. Post-Harvest Management: Proper drying and storage of maize can prevent the growth of *Fusarium* and subsequent fumonisin production.

Also see

• Mycotoxins
• Fusarium
• Sphingolipids
• Esophageal cancer
• Neural tube defects