Single-Dose Toxicity Study on ML171, a Selective NOX1 Inhibitor, in Mice.

BACKGROUND: ML171 is a potent nicotinamide adenine dinucleotide phosphate oxidase (NOX) inhibitor with isoform selectivity only for NOX1. This study is aimed at investigating the safety of ML171 after a single intraperitoneal (IP) injection in mice. METHODS: The toxicity of a single dose of ML171 was evaluated in 6-week-old Institute of Cancer Research (ICR) mice in a good laboratory practice (GLP) laboratory. Twenty-five mice of each sex were assigned to five groups: negative control, vehicle control, and 125, 250, and 500 mg/kg of ML171. All mice were acclimatized for one week before beginning the study. Mice received an IP injection of ML171 or vehicle. The general condition and mortality of the animals were observed. The mice were sacrificed to evaluate histopathology 14 days after the administration of ML171 or vehicle. RESULTS: Bodyweights were not significantly different in any group. Three males and one female died due to ML171 administration in the 500 mg/kg dose group. Autopsies of the surviving mice did not reveal any significant abnormalities after the injection of 125 mg/kg of ML171. However, the anterior lobe edge of the liver was thickened and adhesions between the liver and adjacent organs were observed in mice treated with 250 or 500 mg/kg of ML171. In addition, hypertrophy of centrilobular hepatocytes and inflammatory cell infiltration were observed after injection of 250 and 500 mg/kg of ML171. CONCLUSION: Our results indicate that the lethal IP injection dose of ML171 is 500 mg/kg for both males and females. Mortality were not observed for lower doses of ML171. The safe dose of single IP ML171 in ICR mice was 250 mg/kg or less. Further studies are needed to confirm the safety of ML171 in the human body.

Antitubercular polyhalogenated phenothiazines and phenoselenazine with reduced binding to CNS receptors.

Targeting energy metabolism in Mycobacterium tuberculosis (Mtb) is a new paradigm in the search for innovative anti-TB drugs. NADH:menaquinone oxidoreductase is a non-proton translocating type II NADH dehydrogenase (NDH-2) that is an essential enzyme in the respiratory chain of Mtb and is not found in mammalian mitochondria. Phenothiazines (PTZs) represent one of the most known class of NDH-2 inhibitors, but their use as anti-TB drugs is currently limited by the wide range of potentially serious off-target effects. In this work, we designed and synthesized a series of new PTZs by decorating the scaffold in an unconventional way, introducing various halogen atoms. By replacing the sulfur atom with selenium, a dibromophenoselenazine 20 was also synthesized. Among the synthesized poly-halogenated PTZs (HPTZs), dibromo and tetrachloro derivatives 9 and 11, along with the phenoselenazine 20, emerged with a better anti-TB profile than the therapeutic thioridazine (TZ). They targeted non-replicating Mtb, were bactericidal, and synergized with rifampin and bedaquiline. Moreover, their anti-TB activity was found to be related to the NDH-2 inhibition. Most important, they showed a markedly reduced affinity to dopaminergic and serotonergic receptors respect to the TZ. From this work emerged, for the first time, as the poly-halogenation of the PTZ core, while permitting to maintain good anti-TB profile could conceivably lead to fewer CNS side-effects risk, making more tangible the use of PTZs for this alternative therapeutic application.

Contrasting action of flavonoids on phototoxic effects induced in human skin fibroblasts by UVA alone or UVA plus cyamemazine, a phototoxic neuroleptic.

The potential protective effects of the flavanol catechin, the flavonol quercetin, the flavones, luteolin and rutin, and the isoflavones, genistein and daidzein, against the photo-oxidative stress induced by ultraviolet A radiation (UVA) and by phototoxic reactions resulting from the interaction of UVA with drugs and chemicals, has been assessed with cultured human skin fibroblasts. Lipid peroxidation and cell death have been chosen as model photobiological damage induced by UVA alone or photosensitized by cyamemazine (CMZ) and its photoproduct possessing phototoxic properties. Contrasting effects of flavonoids are observed. The flavanol, the flavonol and the flavones may protect against lipid peroxidation and cell death induced by 30 J cm(-2) of UVA alone or CMZ plus 10 J cm(-2) UVA. On the other hand, an amplification of the photodamage may be observed with isoflavones. A concentration-dependence study demonstrates that among the protective flavonoids, quercetin is the most efficient. The very effective protection brought by quercetin may result from its ability to scavenge reactive oxygen species produced by the photo-oxidative stress. However, the modification of membrane properties and the alteration of the lysosomal function by quercetin may not be neglected in these protective effects. The amplification of the photodamage by isoflavones is in sharp contrast with previous literature data demonstrating photoprotection by genistein. As a consequence, it may be concluded that an eventual antioxidant action of genistein may strongly depend on cells and photosensitizers. Furthermore such contrasting pro-versus anti-oxidant effects have to be taken into account when using flavonoid mixtures of plant extracts.

[The antiarrhythmic activity of the polymeric forms of quinidine, trimecaine, etatsizin, propranolol and verapamil]. / Antiaritmicheskaia aktivnost' polimernykh form khinidina, trimekaina, étatsizina, propranolola i verapamila.

The antiarrhythmic activity and acute toxicity of polymeric formulations of quinidine, trimecaine, ethacizine, propranolol, verapamil which had been immobilized on a cellulose carrier (monocarboxylcellulose) and low molecular analogues were studied in various experimental animals (rats, mice, dogs). The polymeric formulations of trimecaine and verapamil were found to have a higher antiarrhythmic activity in different arrhythmia models than trimecaine and verapamil. The toxicity of all new compounds was no more than the values of conventional antiarrhythmic drugs.

Effects of organoselenium compounds on induction of mouse forestomach tumors by benzo(a)pyrene.

The selenium analogues of three known inhibitors of chemical carcinogenesis were synthesized and the compounds were tested for their ability to inhibit the induction of forestomach tumors in mice by benzo(a)pyrene. Groups of female CD-1 mice were given NIH-07 diet, or NIH-07 diet to which one of the following test compounds had been added: p-methoxyphenol (30 mumol/g diet and 3.3 mumol/g diet); p-methoxybenzeneselenol (3.3 mumol/g diet); benzylthiocyanate (0.045 mumol/g diet); benzylselenocyanate (0.045 mumol/g diet); phenothiazine (3.8 mumol/g diet); and phenoselenazine (3.8 mumol/g diet). The test compounds were administered for 1 week prior to treatment with benzo(a)pyrene, during the 4 weeks of benzo(a)pyrene treatment, and for 1 week after benzo(a)pyrene treatment. Twelve weeks later the mice were sacrificed and forestomach tumors were counted and confirmed histologically as papillomas. p-Methoxyphenol was the most effective inhibitor and was the only one which significantly reduced both the percentage of tumor-bearing animals and the number of forestomach tumors per animal. At the 3.3-mumol/g diet, p-methoxyphenol reduced the number of tumors per animal from 3.3 to 0.8 (P less than 0.0003). p-Methoxybenzeneselenol reduced the number of tumors per animal from 3.3 to 2.0 (P less than 0.05). Benzylthiocyanate showed no significant inhibitory effect, but benzylselenocyanate reduced the number of tumors per animal from 3.3 to 1.7 (P less than 0.01). Phenothiazine significantly enhanced the number of tumors per animal from 3.3 to 6.5 (P less than 0.004). Phenoselenazine had no effect on tumor induction. The results of this study indicate that two synthetic organoselenium compounds, p-methoxybenzeneselenol and benzylselenocyanate, are effective inhibitors of mouse forestomach tumorigenesis induced by benzo(a)pyrene.

[Experimental data on the toxicity of nonachlazine, a new antianginal agent]. / Eksperimental'nye dannye o toksichnosti nonakhlazina--novogo antianginalinogo sredstva

The results obtained by a study of acute and chronic toxicity of nonachlazine--a new original coronary-active agent endowed with antianginal properties are reported. Nonachlazine has been found to have a sufficiently wide range of therapeutic action. With its repeated (for 36 days) oral introduction to rats in an effective dose of 10 mg/kg the drug does not produce any adverse effect on the general condition of the animals, reduces but insignificantly their weight gain, fails to exert any damaging effect on the blood system, does not change biochemical characteristics featuring the function of the liver, nor evokes any pathohistological changes of the internal organs. Nonachlazine has no locally irritating effect on the gastro-intestinal tract and is a compound producing but a slight stress action.