In vitro antileukemic, antioxidant and prooxidant activities of Antoksyd S (C/E/XXI): a comparison with baicalin and baicalein.

There is increasing interest concerning the use of natural antioxidants as low toxic antileukemic compounds. Antoksyd S (C/E/XXI), is a novel herbal drug derived in Poland from the powdered roots of Scutellaria baicalensis, and the biological activities of its major components (baicalin and baicalein) were compared on the human leukemia cell line HL-60. On MTT assay, Antoksyd S (C/E/XXI) showed an obvious cytotoxic effect on HL-60 cells, which was compared with those caused by cisplatin and doxorubicin under the same experimental conditions.

Cytotoxicity, cytoprotection and neurotoxicity of novel deprenyl-related propargylamines, stable nitroxide free radicals, in vitro and in vivo.

Since novel synthesized deprenyl-related derivatives of nitroxides, named "JSAKs", have been shown to possess antioxidative properties, their cytotoxicity on neuronal-like PC-12 cells line was examined. The antiproliferative effect of two selected JSAKs was examined and expressed as IC10, IC50 and IC90, and compared with those of the parent nitroxide (Nx-640), model nitroxide TEMPO and deprenyl. There were substantial differences in the dose-dependence of all the observed antiproliferative and cytotoxic effects.

The possible role of one-electron reduction of aminochrome in the neurodegenerative process of the dopaminergic system.

We present for discussion a possible molecular mechanism explaining the formation of reactive oxygen species involved in the neurodegenerative process of dopaminergic system in Parkinson's disease. This new hypothesis involves one-electron reduction of aminochrome to o-semiquinone radical, which seems to be the reaction responsible for neurodegenerative process of dopaminergic system. Leukoaminochrome o-semiquinone is extremely reactive with oxygen, which reoxidizes by reducing oxygen to superoxide radicals.

Antioxidant properties of newly synthesized N-propargylamine derivatives of nitroxyl: a comparison with deprenyl.

In our search for novel, low-toxic, cell-penetrable and neuroprotective antioxidants, we have designed a number of novel N-propargylamine derivatives of nitroxyl, named "JSAKs". The reactivity and antioxidative potency of two selected JSAKs and their parent nitroxyl against reactive oxygen species (ROS) were examined in vitro, in a cell-free gamma-radiolysis and in model Fenton-type reaction systems and compared with those of deprenyl, the investigated member of adjunct therapies in clinical neurology. The efficiency of JSAKs to suppress the oxidative degradation of a model target (deoxyribose), deprenyl and dopamine, caused by hydroxyl radical (*OH) was also investigated.

Synthesis and antioxidant activity evaluation of novel antiparkinsonian agents, aminoadamantane derivatives of nitroxyl free radical.

Two new analogues of the antiparkinsonian drug 1-aminoadamantane: 4-(1-adamantylamino)-2,2,6,6-tetramethylpiperidine-1-oxyl and 4-(1-adamantylammonio)-1-hydroxy-2,2,6,6-tetramethylpiperidinium dihydrochloride have been synthesized. Their antioxidant activity towards reactive oxygen species (ROS: (z.rad;)OH and O(2)(z.