ENTWINEMENTS

This is a very traditional Japanese diaper, dyed with indigo. I've always thought this an interesting choice for a diaper, given that there is "blue diaper syndrom". Indican, the precursor of indigo in Indigofera and Polygonum tinctorium (Japanese indigo), lives in the human gut as well. Here, from Wikipedia: "Indican is a colourless organic compound, soluble in water, naturally occurring in Indigofera plants. It is a precursor of indigo dye." Indican is a glycoside. Its hydrolysis yields β-D-glucose and indoxyl. Reaction of indoxyl by a mild oxidizing agent, eg. atmospheric oxygen, yields indigo dye. Such a reaction is seen in individuals affected by the blue diaper syndrome, who exhibit a defect in tryptophan metabolism. Tryptophan is first converted to indole, then to indican by bacteria in the gut. Indican is then excreted into the urine and from there into the diaper where, upon exposure to air, it is converted to indigo blue dye.

Very interesting! I've heard tales of the old Japanese taking indigo to prevent snake bite.... If it is made in some people's guts it is likely to be tolerated.