ANTHRAQUINONES-A Naturopathic Compound

Anthraquinones is a potent aromatic compound that besides being used commercially it offers numerous therapeutic benefits such as inhibits cancer growth by inducing apoptosis, relive constipation, ease bowl movement etc. Anthraquinones are found naturally in some plants such as senna, buckthorn, yellow dock etc while it can also be produced using chemical routes such as anthracene oxidation, naphthalene oxidation, condensation of 1, 4-naphthoquinone with butadiene etc. However its intake should strictly be regulated since it may cause some serious side effects.

The selective oxidation of substituted aromatic hydrocarbons and the observation of uncoupling via redox cycling during naphthalene oxidation by the CYP101B1 system

Oxidation of polyaromatic hydrocarbons by P450s can be lowered by redox cycling but CYP101B1 regioselectively hydroxylated substituted naphthalenes and biphenyls.

Bioavailability of Methanobactin to Copper by Methylosinus trichosporium 3011

Methanobactin (mb) is a small, copper binding bioactive peptides produced by methanotrophs. The transition between two forms of methane monooxygenase (MMO) expressed by methanotrophs depends on the amount of copper available in the surrounding. In this paper, the bioavailability of copper(Ⅱ) in the presence of different chelating agents to a representative methanotroph, Methylosinus trichosporium 3011 is studied systematically according to the naphthalene oxidation assay. The result shows that purple naphthol diazo complex may be measured at A530, and along with the increase of the concentration of the copper(Ⅱ), eight kinds of chelating agents have effect on the activity of sMMO. The copper bioavailability has been assessed after the changes in sMMO activity is monitored, it means that copper(Ⅱ) can repress the expression of sMMO as well as reduce its activity. The affinity of mb excreted during growth was also measured and the chelate constants of the chelating agents to copper(Ⅱ) are compared. Based on these studies, strongly binding chelating agents (Log K > 16) added into the medium at a concentration of 20uM were able to reduce copper bioavailability.

Simultaneous Cr(VI) Reduction and Naphthalene Oxidation in Aqueous Solutions by UV/TiO2

The photocatalytic reduction of Cr (VI) and oxidation of naphthalene using UV light and TiO2 were investigated with variations in the pH and Cr (VI)/naphthalene ratio. The photochemical reduction of Cr (VI) single system was not observed, whereas the photochemical oxidation of naphthalene was significantly high. However, the reduction reaction rates of Cr (VI) and oxidation of naphthalene were improved in the system UV/TiO2. The removal of Cr (VI) decreased dramatically with increasing pH, in contrast, the naphthalene removal was not influenced by the pH. The presence of naphthalene functioned as a hole scavenger enhancing the photocatalytic reduction of Cr (VI) by the photogenerated electrons, while the removal of naphthalene was decreasing at increasing Cr (VI) content.

Effects of metal and porphyrin structure on the yield and chemoselectivity of naphthalene oxidation: a comparative study for manganese and iron

Oxidation of naphthalene was performed with various manganese and iron porphyrins as catalysts and metachloroperbenzoic acid, tert-butylhydroperoxide, and hydrogenperoxide as oxidants, in the presence of imidazole as cocatalyst. With m-CPBA, in low concentration of catalyst, iron porphyrin shows a higher catalytic activity than manganese porphyrin, while a greater amount of manganese porphyrin is needed for having a good catalyst. In the presence of excess amount of H 2 O 2 oxidant in CH 3 OH solvent, manganese porphyrin acts better than iron porphyrin; however with the same oxidant and in aprotic solvent such as CH 3 CN : CH 2 Cl 2 again iron shows a higher activity than manganese. Moreover, the effects of metalloporphyrin concentration on the selectivity, activity and stability of catalyst were studied in H 2 O 2-catalytic oxidation.