Membrane-Bound Bisindolyl-Based Chromogenic Probes: Analysis of Cyanogenic Glycosides in Agricultural Crops for Possible Remediation

Cyanogenic glycosides are plant-derived, nitrogen-containing secondary metabolites that release toxic cyanide ions upon hydrolysis by glycosidic enzymes. Therefore, consuming food items enriched with such compounds without proper remediation can cause acute cyanide intoxication. Thus, in this work, we utilize cyanide-responsive oxidized bisindole-based chromogenic probes to detect cyanogenic glycosides, such as amygdalin and linamarin (LOD: 0.12 μM), in phospholipid membranes. The bilayer surface, owing to its distinct microenvironment, enhances both the sensitivity and specificity of the probes toward amygdalin. The chromogenic response (red to yellow) is influenced by the nature of the lipid membrane (order, polarity, and interfacial hydration) as well as the number of bis-indolyl units in the probe molecules. Semiquantitative analysis of food samples before and after cooking revealed that soaking in water at room temperature significantly reduces the cyanogenic glycoside content. The ability to directly detect cyanogenic glycosides in food samples without pretreatment is a notable aspect of this investigation.