What is an extractive matter contained in the juice of the green shucks of the walnut (Juglans regia). It is used medicinally as an alterative, and also as a black hair dye called?

juglandin — An extractive matter contained in the juice of the green shucks of the walnut (Juglans regia). It is used medicinally as an alterative, and also as a black hair dye. (Webster's 1913.)

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