Preliminary Examination of the Toxicity of Spalting FungalPigments: A Comparison between Extraction Methods


Spalting fungal pigments have shown potential in technologies ranging from green energygeneration to natural colorants. However, their unknown toxicity has been a barrier to industrialadoption. In order to gain an understanding of the safety of the pigments, zebrafish embryos wereexposed to multiple forms of liquid media and solvent-extracted pigments with concentrations ofpurified pigment ranging from 0 to 50 mM fromChlorociboria aeruginosa, Chlorociboria aeruginascens,andScytalidium cuboideum.Purified xylindein fromChlorociboria sp. did not show toxicity at any testedconcentration, while the red pigment dramada fromS. cuboideumwas only associated with significanttoxicity above 23.2 uM. However, liquid cultures and pigment extracted into dichloromethane (DCM)showed toxicity, suggesting the co-production of bioactive secondary metabolites. Future researchon purification and the bioavailability of the red dramada pigment will be important to identifyappropriate use; however, purified forms of the blue-green pigment xylindein are likely safe for useacross industries. This opens the door to the adoption of green technologies based on these pigments,with potential to replace synthetic colorants and less stable natural pigments.


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