A brown dye obtained from the husks of walnuts, Juglans regia. Juglone also acts as a natural herbicide, providing a plant-free region for the seed to grow.
See also walnut shell.
Synonyms and Related Terms
5-hydroxy-1,4-naphthoquinone; CI 7550; Natural Brown 7; nucin; regianin; juglona (Esp., Port.)
Yellow crystals. Absorption max = 520 nm
Soluble in chloroform, benzene, alcohol, ether.
Alkaline solutions turn a reddish-purple color
Sources Checked for Data in Record
- Richard S. Lewis, Hawley's Condensed Chemical Dictionary, Van Nostrand Reinhold, New York, 10th ed., 1993
- John S. Mills, Raymond White, The Organic Chemistry of Museum Objects, Butterworth Heineman, London, 2nd ed., 1994
- The Merck Index, Martha Windholz (ed.), Merck Research Labs, Rahway NJ, 10th edition, 1983 Comment: entry 5282
- Encyclopedia Britannica, http://www.britannica.com Comment: "Amensalism." Encyclopædia Britannica. 1 Sept. 2004 .