Juglone

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Juglone

IUPAC name	5-hydroxy-1,4-naphthalenedione
Other names	5-hydroxy-1,4-naphthoquinone 5-hydroxy-p-naphthoquinonejuglone regianin
Identifiers
CAS number	[481-39-0]
RTECS number	QJ5775000
SMILES	CC2=CC(C1=C(O)C=CC=C1C2=O)=O
Properties
Molecular formula	C₁₀H₆ O₃
Molar mass	174.15 g/mol
Appearance	yellow solid
Melting point	155 °C
Solubility in water	slightly sol.
Hazards
R-phrases	R25
S-phrases	S28A S45
Related compounds
Related compounds	quinone
Except where noted otherwise, data are given for materials in their standard state (at 25 °C, 100 kPa) Infobox disclaimer and references

Juglone is an aromatic organic compound with the molecular formula C₁₀H₆O₃. It occurs naturally in the leaves, roots and bark of plants in the Juglandaceae family, particularly the black walnut. Juglone is an allelopathic compound, meaning it is synthesized by one type of plant and affects the growth of another. In the case of juglone, it is toxic or growth-stunting to many types of plants. Landscapers have long known that gardening underneath or near black walnut trees can be difficult. Juglone exerts its effect by inhibiting certain enzymes needed for metabolic function. It is occasionally used as a herbicide.

Because of its tendency to create dark orange-brown stains, juglone has also found use as a coloring agent for foods and cosmetics, such as hair dyes. It is known in the food industry as C.I. Natural Brown 7 or C.I. 75500. Traditionally, juglone has been used as a natural dye for clothing and fabrics, particularly wool, and as ink. Its other names are Iuglon, Juglane, Nucin, Regianin, Walnut extract, Yuglon, NCI 2323 and Oil Red BS. It is an isomer of lawsone.