conclusions our study showed that the triple therapy of nd: yag and nd: yag + co2 fractional and hydroquinone cream had high efficiency and low morbidity compared to twofold treatment with nd: yag and nd: yag + co2 fractional. results seventeen patients with melasma (14 females and three males) with mean (± sd) age of 38.47 (± 6.29) years (range 29 - 53) were included in this study. the only si...

All current routes for the synthesis of hydroquinone utilize benzene as the starting material. An alternate route to hydroquinone has now been elaborated from glucose. While benzene is a volatile carcinogen derived from nonrenewable fossil fuel feedstocks, glucose is nonvolatile, nontoxic, and derived from renewable plant polysacharrides. Glucose is first converted into quinic acid using microb...

In the presence of MnCl2 and a thiol (glutathione, cysteine, 2-nitro-5-thiobenzoic acid) horse radish peroxidase oxidizes p-hydroquinone to p-benzoquinone which in turn immediately adds the thiol present yielding 2-S-substituted p-hydroquinone.

Benzene is an established human carcinogen, producing leukemia, hematotoxicity and perhaps lymphoma. Its carcinogenicity is most likely dependent upon its conversion to phenol and hydroquinone, the latter being oxidized to the highly toxic 1,4-benzoquinone in the bone marrow. Exposure of human lymphocytes and cell lines to hydroquinone has previously been shown to cause various forms of genetic...

The method has been developed and validated for the determination of hydroquinone in liposomal formulation. The samples were dissolved in methanol and evaluated in 293 nm. The validation parameters such as linearity, accuracy, precision, specificity, limit of detection (LOD) and limit of quantitation (LOQ) were determined. The calibration curve was linear in 1-50 µg/mL range of hydroquinone ana...

Pyronin Y (PY) has a strong resonance fluorescence in sulfuric acid medium. The characteristics of the resonance fluorescence spectra and the factors affecting the spectra were studied. A catalytic resonance fluorometry method for the determination of hydroquinone was proposed based on the catalytic effect of hydroquinone on the oxidation of PY by potassium bromate. The oxidation of PY resulted...

Fermentative degradation of hydroquinone, catechol, and phenol was demonstrated with nearly-homogeneous mixed methanogenic cultures obtained from freshwater sediments and sewage sludge by enrichment with the respective phenolic substrates. Gram-negative short rods predominated in these cultures, together with hydrogenand acetate-utilizirtg methanogens. Acetate and methane were the only degradat...

The novel hydroquinone, (E)-2-(4-hydroxy-3-methyl-2-butenyl)-hydroquinone, and known compound, polyporenic acid C, were isolated as matrix metallo-proteinase inhibitors from the mushroom, Piptoporus betulinus.

     Cell cultures of Varthemia persica, Peganum harmala and Pycnocycla spinosa have been studied to evaluate their abilities to bioconvert exogenous hydroquinone. Arbutin is an important substance that has several pharmaceutical applications; therefore, we have established V. persica and P. spinosa cultures which seem to be able to metabolize hydroquinone. C...

The effects of benzene and its metabolites, phenol and hydroquinone, on natural killer (NK) activity in mouse spleen cells in vitro were studied. NK activity was evaluated by the specific release percentage of 51Cr from labeled YAC-1 cells after YAC-1 cells (target cells) were incubated with spleen cells (effector cells) of mice at ratios of effector cells to target cells (E/T) of 100/1, 50/1, ...