Juglone from black walnut

Juglone [481-39-0] (Cl Natural Brown 7 Cl 75500) was isolated from the husks of walnuts in 1856 (50). Juglone belongs to the Juglandaceae family of which there are a number of species Jug/ans cinerea (butter nuts), J. regia (Persian walnuts), and J. nigra (black walnuts). Persian walnuts were known to the ancient Romans who brought them over from Asia Minor to Europe. As early as 1664, the American colonists knew how to extract the brown dye from the nuts of the black walnut and butternut trees, both native to eastern North America (51). 

Juglone (5-hydroxy-1,4-naphthoquinone) is a water-soluble yellow pigment that is exuded from leaves, fruits, bark, and roots of black walnut Juglans nigra), English walnut (J. regia), and hickory (Carya ovata) trees, among others. 

Juglone, a dye known for centuries, is produced from the husks of hlack walnuts. It is also a natural herbicide (weed killer) that kills off competitive plants around the black walnut tree but does not affect grass and other noncompetitive plants. The formula for juglone is C QHg03. 

Juglone, a natural herbicide, is produced from the husks of black walnuts. 

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