Crossword Clue:

INDULINE a blue dye also INDULIN

AnswerCrossword Clue
METHYL... blue (a basic dye)
WOADBlue dye from a plant.
ANILSource of a blue dye.
ANILShrub yielding a blue dye
ANILBlue dye from a plant
INDIGOSPlants that yield a blue dye