Answer: orcin

AnswerCrossword Clue
ORCINCompound derived from lichens.
ORCINChemical solid
orcinwhite, crystalline, water-soluble solid, C7H8O2, sweet but unpleasant in taste, that reddens on exposure to air: obtained from many lichens or produced synthetically and used chiefly as a reagent for certain carbohydrates