Carcinogenic effects of chemical mixtures were examined with a medium-term liver bioassay for carcinogens or a multiorgan medium-term bioassay using male F344 rats. In the medium-term liver bioassay, rats were initially treated with diethylnitrosamine (DEN) at 200 mg/kg body weight, i.p.; after 2 weeks they received chemical mixtures such as 10 different heterocyclic amines at one-tenth or one-...

Ellagic acid (EA) is a naturally occurring polyphenol found in a variety of plants in its free form or in the form of ellagitannin glycosides. In this study, the ellagic acid content of the methanol extracts of Juglans regia L. (Juglandaceae) leaves, Castanea sativa Mill. (Fagaceae) stem bark, and Eucalyptus camaldulensis Dehnh. (Myrtaceae) leaves was determined to develop melanogenesis inhibit...

Some of the anticarcinogenic effects of 2(3)-tert-butyl-4-hydroxyanisole (BHA) are attributable to the induction of detoxifying enzymes in the liver and peripheral tissues. This study was designed to determine if the tissue specificity of enzyme induction could be manipulated by structural modification of BHA. The induction of glutathione S-transferases and quinone reductase (EC 1.6.99.2) by th...

The kinetics of the reactions between sodium nitrite and phenol or m-, o-, or p-cresol in potassium hydrogen phthalate buffers of pH 2.5–5.7 were determined by integration of the monitored absorbance of the C-nitroso reaction products. At pH . 3, the dominant reaction was C-nitrosation through a mechanism that appears to consist of a diffusion-controlled attack on the nitrosatable substrate by ...

A tyrosinase-directed therapeutic approach for treating malignant melanoma uses depigmenting phenolic prodrugs such as 4-hydroxyanisole (4-HA) for oxidation by melanoma tyrosinase to form cytotoxic o-quinones. However, in a recent clinical trial, both renal and hepatic toxicity were reported as side effects of 4-HA therapy. In the following, 4-HA (200 mg/kg i.p.) administered to mice caused a 7...

The carcinogenicity of low dietary levels of the antioxidants butylated hydroxyanisole (BHA), caffeic acid, sesamol, 4-methoxyphenol (4-MP) and catechol, known to target the forestomach or glandular stomach, were examined alone or in combination in a 2-year long-term experiment and their modifying effects assessed in a medium-term multiorgan model. In the carcinogenicity study, groups of 30-31 ...

Glutathione S-transferase (GST) and multidrug resistance-associated proteins (MRPs) play major roles in drug resistance in melanoma. In this study, we investigated caffeic acid phenethyl ester (CAPE) as a selective GST inhibitor in the presence of tyrosinase, which is abundant in melanoma cells. Tyrosinase bioactivates CAPE to an o-quinone, which reacts with glutathione to form CAPE-SG conjugat...

Rainbow trout liver microsomes were used to study the O-demethylation and ring hydroxylation of 4-methoxyphenol (4-MP) (4-hydroxyanisole) at 11 and 25°C by directly measuring the production of the primary metabolite hydroquinone (HQ), 4-methoxycatechol (4-MCAT), and additional metabolites. An HPLC method with integrated ultraviolet (UV) and electrochemical detection (ECD) was developed for meta...

Anisole, phenyl ether (Ph-O-Me, Figure 1) usually used as a starting material for various pharmaceutical/flavonoid products and as solvent in organic synthesis and physical studies [1]. It is used for the synthesis of raw material for drugs such as cyclofenil, in treating Raynaud’s phenomenon in people with scleroderma [2], and tramadol hydrochloride, that is used for the relief of moderate or ...

Reported is the synthesis and characterization of guest-free and guest-included frameworks assembled from the anionic metal complex [Fe(ox)3] 3‐ and the cationic diprotonated 4,4′-bipyridinium (H2bpy) or 1,2-bis(4-pyridinium)ethylene 2+ (H2bpye) linkers, where the complex and linkers are bonded by multiple charge-assisted hydrogen bonds. In some of the compounds additional barium cations serve ...