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Chemical investigation of different crude extracts from Teucrium ramosissimum leaves. Correlation with their antigenotoxic and antioxidant properties.

The effect of extracts obtained from Teucrium ramosissimum leaves on genotoxicity and SOS response induced by aflatoxin B(1) (0.5 µg/assay) as well as nitrofurantoin (5 µg/assay) was investigated in a bacterial assay system, i.e., the SOS chromotest with Escherichia coli PQ37. The T. ramosissimum tested extracts exhibited no genotoxicity either with or without the external S9 activation mixture. However, all the extracts, particularly the total oligomers flavonoids (TOF) extract significantly decreased the genotoxicity induced by aflatoxin B(1) and nitrofurantoin. Antioxidant capacity of the tested extracts was evaluated using the enzymatic (xanthine/xanthine oxidase assay) (X/XOD) and the non-enzymatic (NBT/Riboflavine assay) systems. TOF extract was the most effective one in inhibiting both xanthine oxidase activity and NBT reduction. Our findings emphasize the potential of T. ramosissimum to prevent mutations and also its antioxidant effect.

Assessment of phenolic content, free-radical-scavenging capacity genotoxic and anti-genotoxic effect of aqueous extract prepared from Moricandia arvensis leaves.

The present study was undertaken to provide a set of data on the safety of an aqueous extract (AQE) from Moricandia arvensis. For this reason, Escherichia coli tested strains PQ35 and PQ37 were used to detect induction of DNA lesions by AQE. The SOS Chromotest showed that AQE induced a marginally genotoxic effect, as expressed by the induction factor (IF) value only with E. coli PQ37 tested strain (IF=1.77 at a dose of 250 microg/assay). The measurement of the anti-genotoxic activity of the AQE was also studied by inhibition of beta-galactosidase induction. A significant anti-genotoxic effect was observed with different tested doses of AQE, which suggests that M. arvensis extract has the potential to protect DNA from the action of nitrofurantoïn (NF) and free radicals generated by hydrogen peroxide (H2O2). In addition to anti-genotoxic activity, AQE showed a free-radical-scavenging capacity towards ABTS+* and DPPH*. Total phenolic content was also evaluated following Folin-Ciocalteu method and results indicated high correlation between total phenol content and anti-genotoxic and antioxidant activities for AQE, but the highest correlation was showed with its capacity to stabilize ABTS+* (R2=0.9944).

Phenolic constituents of galla Rhois with hepatoprotective effects on tacrine- and nitrofurantoin-induced cytotoxicity in Hep G2 cells.

The bioassay-guided fractionation of the MeOH extract of Galla Rhois furnished two hepatoprotective compounds, an equilibrium mixture of 3-galloyl-gallic acid and 4-galloyl-gallic acid isomers (3), 1,2,3,4,6-penta-O-galloyl-beta-D-glucose (4), and two inactive phenolic compounds, gallic acid methyl ester (1) and gallic acid (2). Compounds 3 and 4 showed significant hepatoprotective effects with EC50 values of 70.39+/-5.4 and 29.51+/-0.7 microM, respectively, against tacrine-induced cytotoxicity, and 150.9+/-6.4 and 23.81+/-0.5 microM, respectively, against nitrofurantoin-induced cytotoxicity in Hep G2 cells.

Hepatoprotective constituents of Cudrania tricuspidata.

Phytochemical investigation of the MeOH extract of the root barks of Cudrania tricuspidata Bureau (Moraceae), as guided by hepatoprotective activity in vitro, furnished four isoprenylated xanthones, cudratricusxanthone A (1), cudraxanthone L (2), cudratricusxanthone E (3), and macluraxanthone B (4). All of these compounds showed the significant hepatoprotective effect on tacrine-induced cytotoxicity in human liver-derived Hep G2 cells. Compounds 1, 2, and 4 also exhibited the significant hepatoprotective effect on nitrofurantoin-induced cytotoxicity in human liver-derived Hep G2 cells.

Alpha-tocopherol succinate does not mitigate nitrofurantoin-induced changes in the glutathione and protein thiol status of the isolated perfused rat liver.

Because it had been suggested that alpha-tocopherol might protect protein thiols (PSH) from oxidation, we were interested in determining if alpha-tocopherol could prevent or mitigate nitrofurantoin-induced changes in the glutathione (GSH) or PSH status of the liver. Isolated rat livers were perfused in the single pass mode for 310 min with Krebs-Henseleit buffer or the same buffer containing 25 nmol/ml of alpha-tocopherol succinate. Treated livers were exposed to 1200 nmol/ml of nitrofurantoin from 30 to 90 min. In control (no nitrofurantoin or alpha-tocopherol) livers, tissue levels of GSH and PSH were maintained at 78 +/- 6% and 94 +/- 6% of their initial values, but alpha-tocopherol levels declined from 34.9 +/- 0.6 nmol/g to 26 +/- 1.5 nmol/g. In the nitrofurantoin-only livers, GSH and PSH tissue levels fell to 17 +/- 10% and 49 +/- 6% of their initial levels (P less than 0.05, vs. controls), alpha-Tocopherol levels fell from 31.7 +/- 4.8 nmol/g to 17.0 +/- 2.8 nmol/g. In the alpha-tocopherol-supplemented, nitrofurantoin-treated livers, initial tissue levels of alpha-tocopherol were elevated to 43.8 +/- 1.4 nmol/g (P less than 0.05), but fell to 26.1 +/- 4.2 nmol/g. Their GSH and PSH tissue levels also declined to 7 +/- 3% and 56 +/- 8% of their initial values (P less than 0.05, vs. controls). Thus, it appeared that alpha-tocopherol supplementation was unable to prevent nitrofurantoin-induced changes in the GSH or PSH status of the liver.

Furazolidone and nitrofurantoin in the treatment of experimental Pneumocystis carinii pneumonia.

Furazolidone and nitrofurantoin, oral nitrofuran derivatives with broad-spectrum antimicrobial properties already in clinical use, were compared for activity against Pneumocystis carinii in an immunosuppressed rat model of P. carinii pneumonia. Furazolidone exhibited only slight activity as a prophylactic agent but was moderately effective in the therapy of pneumocystosis. The median histologic score and organism count fell from 4+ and 10(8) to 10(9) cysts per lung, respectively, in the controls to 1+ to 2+ and 10(7) to 10(8) cysts per lung, respectively, in the furazolidone-treated groups. However, these results were not as good as those obtained with the standard drug, trimethoprim-sulfamethoxazole (0+, 10(6) to 10(7) cysts per lung). Nitrofurantoin showed little anti-P. carinii activity despite different doses or drug preparations. The high doses of furazolidone used here and their toxic effects on the rats will probably discourage investigation of this drug in the treatment of pneumocystosis in humans. Nevertheless, since many nitrofurans have been synthesized, further exploration of this class of compounds might be helpful in developing new anti-P. carinii agents or in studying structure-activity relationships.

Synthetic seleno-organic compound with glutathione peroxidase-like activity in the chick.

The glutathione peroxidase activity catalyzed by the seleno-organic anti-inflammatory drug Ebselen (registered under the trademark of the Natterman Corp. Cologne, FRG) [PZ51, 2-phenyl-1,2-benzisoselenazol-3(2H)on], as measured by NADPH oxidation, was inhibited in vitro by the selenium-dependent glutathione peroxidase (SeGSHpx) inhibitors aurothioglucose and D-(-)penicillamine HCl. Vitamin E- and selenium-deficient chicks were given 0, 80 or 320 ppm PZ51 in diets devoid of vitamin E and supplemented with low levels of sodium selenite (0.04 ppm selenium added to the basal diet containing ca. 0.015 ppm selenium) when a small number of chicks (ca. 13%) had exudative diathesis (ED). By 24 hr, the high PZ51 dose (320 ppm) delayed the onset of ED compared to untreated controls. Similarly, vitamin E-deficient chicks fed diets containing 0, 80, 160, 320, 640 or 1280 ppm PZ51 and supplemented with 0.04 ppm selenium showed ED in inverse proportion to log PZ51 dose. Plasma and liver post-mitochondrial supernatant samples from these chicks also exhibited log-linear relationships between dietary PZ51 level and selenium content or SeGSHpx-like activity. The amount of SeGSHpx-like activity for chicks given PZ51 above that determined for untreated chicks was extractable into ethanol, indicating that those PZ51-associated increases were not due to protein-bound selenium or SeGSHpx. This suggests that selenium from PZ51 was not available to support synthesis of SeGSHpx. Dietary PZ51 (1280 ppm) or selenium (0.1 ppm) alone or in combination decreased the acute lethalities of nitrofurantoin or paraquat in vitamin E-adequate chicks. The results indicate that SeGSHpx-like activity in selenium-deficient chicks is increased by oral administration of PZ51, which appears to mimic the true enzyme by affording protection against clinical signs of selenium deficiency (i.e. ED) and pro-oxidant drug lethality.

Selenium-dependent glutathione peroxidase inhibitors increase toxicity of prooxidant compounds in chicks.

The acute lethality of paraquat (1, 1'-dimethyl-4,4'-bipyridinium dichloride; also methyl viologen) for chicks was reduced in a dose-dependent manner by adding to a selenium-deficient torula-yeast-based diet low concentrations (0.02-0.04 ppm) of selenium (Se) as either Na2SeO3, selenomethionine or a high Se yeast without significantly increasing plasma Se-dependent glutathione peroxidase (Se GSH-Px) activity. Similarly, chicks orally dosed with 100 mg nitrofurantoin [N-(5-nitro-2 furfurylidine)-1-aminohydantoin] per kilogram had highest mortalities in the Se-deficient (unsupplemented) group; lowest mortalities occurred in chicks supplemented with 0.2 ppm Se; chicks supplemented with 0.02 ppm Se survived at rates not statistically different from chicks either unsupplemented or supplemented with 0.2 ppm Se. The activities of SeGSH-px in various vital organs were significantly elevated by supplementation of 0.2 ppm Se to Se-deficient chicks; but only kidney SeGSH-Px increased with 0.02 ppm Se. Additionally, no histopathology was observed in the vital organs of moribund chicks 5 or 24 h following nitrofurantoin administration at any dietary level of Se tested. Exposure of chicks to oxygen enhanced the toxicity of nitrofurantoin, but the protective effect of dietary Se was still evident. Two inhibitors of SeGSH-Px, D(-)-penicillamine X HCl and aurothioglucose, were found to increase the lethalities of both nitrofurantoin and paraquat. Aurothioglucose was most effective when administered simultaneously with the prooxidant compounds; penicillamine increased toxicities only when administered at least 24 h before paraquat or nitrofurantoin (it decreased nitrofurantoin lethality and did not significantly alter paraquat toxicity if given simultaneously). These data support an hypothesis that the protection offered by dietary Se against the acute toxicities of the prooxidant compounds paraquat and nitrofurantoin may be provided by SeGSH-Px in the chick.

Effect of selenium and vitamin E deficiency on nitrofurantoin toxicity in the chick.

The acute toxicity of nitrofurantoin was studied in the young chick deficient in selenium (Se) and/or vitamin E (E). This new and potentially valuable animal model proved to be very sensitive to the toxicity of this nitro drug. The 48-hour LD50 for nitrofurantoin decreased from 148 mg/kg in the Se- and E-supplemented chicks to 53 mg/kg in Se- and E-deficient chicks. The addition of Se (0.10 ppm as Na2SeO3) alone, but not E (100 IU/kg diet as dl-alpha-tocopheryl acetate) reduced the toxicity of nitrofurantoin, so that the LD50 for the chicks given Se alone was the same as the LD50 for the E- and Se-fed chicks. Se and E deficiency significantly decreased the Se-dependent glutathione peroxidase and the plasma tocopherol levels. Hepatic glutathione content, hepatic catalase and superoxide dismutase were unchanged by the dietary treatments. However, a toxic dose of nitrofurantoin significantly decreased hepatic glutathione content over time. These data support the concept that the toxicity of this drug may be mediated in part by an oxidative stress generated by the futile reductive metabolism of the parent compound.

Acute pulmonary injury in rats by nitrofurantoin and modification by vitamin E, dietary fat, and oxygen.

The subcutaneous administration of nitrofurantoin to rats caused severe pulmonary damage, characterized by edema, congestion, and hemorrhage. The acute lethality of the drug was greater in rats fed vitamin E-deficient diets high in polyunsaturated fats as compared to rats fed the NIH open-formula diet. The survival times of vitamin E-deficient rats were increased if such animals were fed diets supplemented with vitamin E and/or diets containing saturated fat (lard) for 3 weeks before administration of nitrofurantoin. The toxicity of nitrofurantoin was enhanced in both the rats deficient in vitamin E and in those given vitamin E supplements and exposed to O2-enriched atmospheres. These results, in conjunction with previous metabolic studies in vitro showing redox cycling and O2 activation in rat lung microsomes in the presence of nitrofurantoin, illustrate certain similarities with the lung-toxic herbicide, paraquat, and raise the question of whether the 2 agents may be capable of damaging lungs by a common mechanism.

The nitrofurans as sperm-immobilizing agents, their tissue toxicity, and their clinical application in vasectomy.

Nitrofurantoin sodium and nitorfurazone, in certain critical concentrations, have the ability to immobilize spermatozoa. In this study, this effect was consisitent with both 5:1, and 10:1 dilutions. Histologic examination of the effects of these drugs as intraoperative vas irrigants revealed no apparent tissue toxicity in the guinea pig. Clinically, we found intraoperative vas irrigation with both of these nontoxic drugs to be of value in attaining azoospermia immediately postvasectomy. Therefore, they appear to be useful supplements to vasectomy.