The role of the quinone group in the antitumor activity of quinone alkylating agents, such as mitomycin C and 2,5-diaziridinyl-3,5bis(carboethoxyamino)-l,4-benzoquinone, is still uncertain. The quinone group may contribute to antitumor activity by inducing DNA strand breaks through the formation of free radicals and/or by influencing the alkylating activity of the quinone alkylators. The cytoto...

A unified synthesis of several quinone sesquiterpenes is described herein. Essential to this strategy is a novel radical addition reaction that permits the attachment of a fully substituted bicyclic core 16 to a variably substituted quinone 10. The addition product 15 can be further functionalized, giving access to natural products with a high degree of oxygenation at the quinone unit. The quin...

Quinones permeate our biotic environment, contributing to both homeostasis and cytotoxicity. All quinones generate reactive oxygen species through redox cycling, while partially substituted quinones also undergo arylation (Michael adduct formation) yielding covalent bonds with nucleophiles such as cysteinyl thiols. In contrast to reactive oxygen species, the role of arylation in quinone cytotox...

Purpose: To establish the method for the analysis of rifampin quinone and hydrazone in fixeddose combination tablets (FDC) containing rifampicin with or without sodium ascorbate as an additive. Methods: The International Pharmacopoeial (IP) method for the estimation of rifampin quinone in FDC was modified. The extraction solvent (methanol/buffer mixture) of the IP method was replaced with ethyl...

Quinones are widespread secondary metabolites that function as signal molecules between organisms in the rhizosphere. Quinones are particularly important in the exchange of chemical signals between plant roots, a phenomenon classically termed allelopathy. The bioactivity of quinones is due in large part to radical intermediates formed during redox cycling between quinone and hydroquinone states...

Despite the beneficial effects of tamoxifen in the treatment and prevention of breast cancer, long-term usage of this popular antiestrogen has been linked to an increased risk of developing endometrial cancer in women. One of the suggested pathways leading to the potential toxicity of tamoxifen involves its oxidative metabolism to 4-hydroxytamoxifen, which may be further oxidized to an electrop...

The role of the quinone group in the antitumor activity of quinone alkylating agents, such as mitomycin C and 2,5-diaziridinyl-3,5-bis(carboethoxyamino)-1,4-benzoquinone, is still uncertain. The quinone group may contribute to antitumor activity by inducing DNA strand breaks through the formation of free radicals and/or by influencing the alkylating activity of the quinone alkylators. The cytot...

Recent findings that 2-anilo-5-[(4-methylpentan-2-yl)amino]cyclohexa-2,5-diene-1,4-dione (6PPD-quinone), the transformation product of a common tire rubber antioxidant, is acutely toxic in stormwater-impacted streams has highlighted need for better understanding contaminants urban runoff. This study represents one first reports 6PPD-quinone and other rubber-derived compounds stormwater snowmelt...