5-гидрокси-p-нафтохинон

Описание

Juglone (5-hydroxynapthoquinone), is found in the leaves and other parts of walnut, hickory and pecan (1,2). Juglone is synthesized from isochorismic acid (a product of the shikimic acid pathway) and 2-oxo-glutaric acid (3). In plant tissue juglone exists as a free compound or as a glycoside (3,4). Action of a glucosidase releases 1,4,5-trihydroxynapthalene, which is then oxidized to juglone (3,4).

Химические свойства

Orange to brown crystalline powder

Использование

antineoplastic, antifungal, antioxidant, Pin 1 inhibitor

Определение

ChEBI: A hydroxy-1,4-naphthoquinone that is 1,4-naphthoquinone in which the hydrogen at position 5 has been replaced by a hydroxy group.

Общее описание

This substance is a primary reference substance with assigned absolute purity (considering chromatographic purity, water, residual solvents, inorganic impurities). The exact value can be found on the certificate. Produced by PhytoLab GmbH & Co. KG

Фармаколо?гия

Juglone is probably best known as the allelochemical produced by black walnut. The glucoside of juglone leaches from the leaves and branches of black walnut, where it is converted to juglone in the soil. Juglone is toxic to certain plant species and also inhibits the germination of seeds (4). Thus its allelopathic activity may be the result of both phytotoxicity and a germination inhibitor. Juglone is also antifungal (1,5) and attempts to correlate its presence with disease resistance in pecan, black walnut, and hickory to several fungal pathogens have been reported (1,2,5,6). Positive correlations have been found for resistance of juvenile leaves of black walnut to anthracnose caused by Gnomia leptostyla (5) and of some Carya species to the scab pathogen Cladosporium carygenum (2). In some pecans (C. illinoensis), juglone may act as both a preformed and an induced defense factor because concentrations of juglone increase after infection by fungi (2). No correlation between juglone glycoside concentration in pecan leaves and resistance pecan to C. carygenum has been reported (6). Free juglone and the glycosides increase after infection, but these increases could not be correlated with scab resistance (6).

Методы очистки

Crystallise Juglone from *benzene/pet ether or pet ether. [Beilstein 8 III 2558, 8 IV 2368.]