About Fumonisins
Fumonisins are polyketide-derived sphinganine analogs produced principally by Fusarium verticillioides and F. proliferatum on corn (maize). FB1 is the most abundant and toxic variant; FB2 and FB3 are minor. The molecule's structural similarity to the endogenous sphingoid base sphinganine is the basis of its mechanism. IARC classifies FB1 as Group 2B.
Chemistry
Fumonisins have a long-chain backbone with two tricarballylic acid esters and primary hydroxyl, amino, and methyl substituents. The geometry of the backbone closely resembles sphinganine (the endogenous precursor of ceramide and downstream sphingolipids), and this resemblance is the basis for the molecule's enzyme inhibition mechanism.
Mechanism
Fumonisins inhibit ceramide synthase by competitive binding with sphinganine. The result is disrupted sphingolipid biosynthesis: sphinganine accumulates intracellularly, complex sphingolipids are depleted, and downstream signaling pathways (apoptosis regulation, membrane composition, cell-cell adhesion) are affected. Mechanism description is cellular only.
Producing organisms
| Species | Panel | Notes |
|---|---|---|
| Fusarium spp. | Extended | F. verticillioides (primary), F. proliferatum |
Conditions of production
Production at Aw ≥ 0.93 with temperature optimum around 30 °C. The principal substrate is corn; rice and sorghum contamination is occasional but minor by comparison. Production is not associated with indoor water-damage scenarios: fumonisins appear in indoor environments via grain-handling routes (corn-based feed, food storage, pet food) rather than via building moisture.
Natural occurrence
Corn and corn products globally[1]. Fumonisins are among the most prevalent cereal mycotoxin contaminants in maize-growing regions worldwide. Indoor relevance is low for residential ERMI scenarios; the relevant indoor reservoirs are corn-based dry goods, animal feed, and pet food rather than building materials.
Regulatory references
IARC carcinogen classification: Group 2B (possibly carcinogenic to humans). FB1 specifically is the classified compound[3].
Related mycotoxins
Fumonisins are biosynthetically related to other polyketide-derived natural products but are not directly related to other indoor mycotoxin families. The endogenous sphingoid bases sphinganine and sphingosine and the ratio between them serve as exposure biomarkers in fumonisin research.
References
- Marasas WF. Discovery and occurrence of the fumonisins: a historical perspective. Environ Health Perspect. 2001;109(suppl 2):239–243.
- Voss KA, Smith GW, Haschek WM. Fumonisins: toxicokinetics, mechanism of action and toxicity. Food Chem Toxicol. 2007;45:1–17.
- International Agency for Research on Cancer. IARC Monographs on the Evaluation of Carcinogenic Risks to Humans, Vol. 82: Some Traditional Herbal Medicines, Some Mycotoxins, Naphthalene and Styrene. Lyon: IARC; 2002.