The effect of hydroxy substitution on 1,4-naphthoquinone toxicity to cultured rat hepatocytes was studied. Toxicity of the quinones decreased in the series 5,8-dihydroxy-1,4-naphthoquinone greater than 5-hydroxy-1,4-naphthoquinone greater than 1,4-naphthoquinone greater than 2-hydroxy-1,4-naphthoquinone, and intracellular GSSG formation decreased in the order 5,8-dihydroxy-1,4-naphthoquinone gr...

Reaction of 1,2-naphthoquinone with primary amines gives a 2-amino-1,4-naphthoquinone derivative which is equivalent to 1,2 to 1,4 carbonyl transposition. For example the reaction of 1,2-naphthoquinone with 4-methoxyaniline gives 2-(4-methoxyanilino)-naphthoquinone-1,4-(4-methoxyanil) (1) and with n-butylamine gives 2-(butylamino)-naphthoquinone-1,4-butylimine (2) respectively. The compounds 1 ...

DT-diaphorase catalysed the reduction of 1,4-naphthoquinones with hydroxy, methyl, methoxy and glutathionyl substituents at the expense of reducing equivalents from NADPH. The initial rates of quinone reduction did not correlate with either the half-wave reduction potential (E1/2) value (determined by h.p.l.c. with electrochemical detection against an Ag/AgCl reference electrode) or the partiti...

Symmetrical and unsymmetrical 3-halo- or 3-methoxy- substituted 2-dibenzoylamino- 1,4-naphthoquinone analogs were synthesized with an average yield of 45% via sodium hydride promoted bis-acylation of 2-amino-3-chloro-1,4-naphthoquinone, 2-amino-3-bromo-1,4-naphthoquinone and 2-amino-3-methoxy-1,4-naphthoquinone.

The antipruritic effects of orally administered 1,4-naphthoquinone derivatives and related compounds on compound 48/80-induced scratching behavior in mice were studied. 2-Hydroxy-3-(2-hydroxyethyl)-1,4-naphthoquinone, ferulic acid, 2,2'-methylenebis(3-hydroxy-1,4-naphthoquinone), and 2,2'-ethylidenebis(3-hydroxy-1,4-naphthoquinone) (impatienol) all exhibited significant antipruritic activity. H...

Four different methods were evaluated for the determination of the creatinine content of a seriesof 24-hour urine samples. The results indicate that the methods of Folin, Hare, and Van Pilsum give essentially the same values. The precision of the method of Sullivan and Irreverre was extremely poor and the values obtained were 2-8 times higher than those obtained by the other technics. The compo...

Quinones such as 1,4-naphthoquinones are abundant in nature and naphthoquinone based natural products are known to possess anticancer activity. This pharmacophore is known to convey anticancer activity to some drugs such as streptonigrin, mitomycin A, etc. We synthesized and characterized different classes of naphthoquinone derivatives including bis naphthoquinone, 2-arylaminonaphthoquinone, be...

From the treatment of 5-hydroxy-1,4-naphthoquinone (juglone) with acetic anhydride and H2SO4 followed subsequently by treatment with methanolic HCl, 5-hydroxy-3-methoxy-1,4-naphthoquinone (3-methoxy juglone) and 8-hydroxy-4-methoxy-1,2-naphthoquinone were obtained as products rather than the anticipated product 2,5-dihydroxy-1,4-naphthoquinone (2-hydroxy juglone). The reaction and the identific...

Naphthoquinones have been reported to be toxic to liver cells in vitro. Protein modification is associated with naphthoquinone-induced cytotoxicity. In addition, 1,2-naphthoquinone was found to bind covalently to cysteine residues of proteins of lung Clara cells incubated with naphthalene. To further identify the target proteins of the naphthoquinone, we raised polyclonal antibodies by immunizi...

Time-resolved visible and infrared absorption difference spectroscopy data at both 298 and 77 K were obtained using cyanobacterial menB (-) mutant photosystem I particles with several non-native quinones incorporated into the A1 binding site. Data was obtained for photosystem I particles with phylloquinone (2-methyl-3-phytyl-1,4-naphthoquinone), 2-bromo-1,4-naphthoquinone, 2-chloro-1,4-naphthoq...