Drug repositioning of anti-microbial agent nifuratel to treat mast cell-mediated allergic responses.

Objectives: Our objective was to assess the effects and mechanisms of nifuratel on IgE-mediated mast cell (MC) degranulation and anaphylaxis in both in vitro and in vivo settings.Methods: The anti-allergic activity of nifuratel was evaluated in mast cell cultures and the passive cutaneous anaphylaxis (PCA) model. The effects of nifuratel on signaling pathways stimulated by antigen in mast cells were measured by immunoblotting, immunoprecipitation, in vitro protein tyrosine kinase assay, and other molecular biological methods.Results: Nifuratel reversibly inhibited antigen-induced degranulation of MCs (IC50, approximately 0.34 µM for RBL-2H3 cells; approximately 0.94 µM for BMMCs) and suppressed the secretion of inflammatory cytokines IL-4 (IC50, approximately 0.74 µM) and TNF-α (IC50, approximately 0.48 µM). Mechanism studies showed that nifuratel inhibited the phosphorylation of Syk by antigen via the inhibition of recruitment of cytosolic Syk to the É£ subunit of FcεRI, and decreased the activation of Syk downstream signaling proteins LAT, Akt, and MAPKs. Finally, nifuratel dose-dependently suppressed the IgE-mediated passive cutaneous anaphylaxis in mice (ED50, approximately 22 mg/kg).Conclusion: Our findings suggest that nifuratel inhibits pathways essential for the activation of mast cells to suppress anaphylaxis, thereby indicating that the anti-microbial drug, nifuratel, could be a potential drug candidate for IgE-mediated allergic disorders.

Nanoparticle mediated codelivery of nifuratel and doxorubicin for synergistic anticancer therapy through STAT3 inhibition.

Chemotherapy is one of the most potent strategies to treat gastric cancer in clinic. However, the resistance of cancer cells to chemotherapeutics is a remarkable impediment to the treatment. Moreover, signal transducer and activator of transcription 3 (STAT3) is a critical transcriptional factor that over-activated in gastric cancer, and highly involved in the induction of chemoresistance. In this study, we developed poly (lactic-co-glycolic acid) (PLGA) nanoparticles to achieve the simultaneous codelivery of doxorubicin (DOX) and nifuratel (NIF, a novel STAT3 inhibitor) for enhanced cancer therapy. The synergistic effect of DOX and NIF against cancer cells was evaluated in gastric cancer cells. PLGA nanoparticles with an optimal ratio of DOX and NIF (DNNPs) were prepared and characterized. The cellular uptake and anticancer effects of DNNPs were investigated, and the underlying mechanisms were further explored. DNNPs presented as a spherical shape, provided sustained release profiles, and exhibited significantly increased uptake and cytotoxicity in gastric cancer cells. Mechanism studies showed that DNNPs significantly induced mitochondrial-dependent apoptosis and inhibited STAT3 phosphorylation, explaining the enhanced anticancer effect. These results suggested that DNNPs represented a promising strategy against gastric cancer by inhibiting the STAT3 pathway and amplifying apoptosis.

Bacterial vaginosis, Atopobium vaginae and nifuratel.

As bacterial vaginosis (BV) is a potential cause of obstetric complications and gynecological disorders, there is substantial interest in establishing the most effective treatment. Standard treatment - metronidazole or clindamycin, by either vaginal or oral route � is followed by relapses in about 30% of cases, within a month from treatment completion. This inability to prevent recurrences reflects our lack of knowledge on the origins of BV. Atopobium vaginae has been recently reported to be associated with BV in around 80% of the cases and might be involved in the therapeutic failures. This review looks at the potential benefits of nifuratel against A. vaginae compared to the standard treatments with metronidazole and clindamycin. In vitro, nifuratel is able to inhibit the growth of A. vaginae, with a MIC range of 0.125-1 µg/mL; it is active against G. vaginalis and does not affect lactobacilli. Metronidazole is active against A. vaginae only at very high concentrations (8-256 µg/mL); it is partially active against G. vaginalis and also has no effect on lactobacilli. Clindamycin acts against A. vaginae with an MIC lower than 0.125 µg/mL and is active on G. vaginalis but it also affects lactobacilli, altering the vaginal environment. These observations suggest that nifuratel is probably the most valid therapeutic agent for BV treatment.

In vitro activity of nifuratel on vaginal bacteria: could it be a good candidate for the treatment of bacterial vaginosis?

Bacterial vaginosis is characterized by a shift of the physiological flora to a diverse spectrum of bacteria, where Gardnerella vaginalis and Atopobium vaginae are the most important markers. In this study, the antimicrobial activity of nifuratel against G. vaginalis, A. vaginae, and lactobacilli was compared with that of the two currently used antibiotics metronidazole and clindamycin. Results suggest that nifuratel has a better spectrum of activity, being highly active against G. vaginalis and A. vaginae without affecting lactobacilli.

Microbiological and pharmaco-toxicological profile of nifuratel and its favourable risk/benefit ratio for the treatment of vulvo-vaginal infections. A review.

Nifuratel (CAS 4936-47-4) is a furane-derivative provided with a strong trichomonicidal activity equivalent to that of metronidazole (CAS 443-48-1); it has a broad antibacterial spectrum of action, including both Gram-negative and Gram-positive organisms. It is active against Chlamydia trachomatis and Mycoplasma spp. and has also some degree of activity against Candida spp. and mycetes. Its broad spectrum of action, confirmed by in vitro and in vivo studies, covers virtually all the micro-organisms responsible for the infections of the genito-urinary tract. Nifuratel has a very safe toxicological profile. It is practically non-toxic in acute tests in mice and rats and is also well tolerated after repeated oral and intravaginal administrations. Nifuratel is devoid of teratogenic effects. The comparison among past and recent clinical studies confirms that, in contrast to metronidazole, no resistance phenomena to the treatment with nifuratel are reported. The drug can be used during pregnancy due to the absence of teratogenic effects. In conclusion, nifuratel shows a very favourable risk/benefit ratio for the treatment of patients with vulvo-vaginal infections.

Comparative in vitro activity of five nitrofurans.

Five nitrofurans- nitrofurantoin, nifuratel, nitrofurazone, furazolidone and and SQ 18,506--have been tested against 201 microbial strains. Escherichia coli, Streptococcus faecalis, micrococci and Staphylococcus epidermidis were sensitive to all five compounds; furazolidone and SQ 18,506 were the most active against these species. Klebsiella aerogenes was less sensitive, and Proteus spp., Providencia stuartii and Pseudomonas aeruginosa strains were resistant. Nifuratel was inhibitory for some Candida albicans strains, and SQ 18,506 was highly active against this species. Nifuratel was judged overall to have superior in vitro antimicrobial properties to nitrofurantoin.

Sensitivity of Trichomonas vaginalis to metronidazole, tinidazole, and nifuratel in vitro.

Prompted by the sensitivity of trichomonads to metronidazole and nifuratel in clinical practice, a study was conducted in 1971-1972 of 63 consecutive strains of Trichomonas vaginalis isolated from women with clinically refractory vaginal discharge. Their susceptibility to metronidazole, tinidazole, and nifuratel was tested, using a serial tube dilution technique. The minimum concentrations which in 48 hrs caused immobilization and lysis of trichomonads cultured in Diamond's medium was assessed. No differences in drug potency could be determined. The median trichomonistatic and trichomonicidal concentrations were 0-1 and 0-6 mug/ml. respectively when using an inoculum of 10,000 organisms per ml. An inoculum of 100,000 per ml. resulted in inhibitory concentrations of 1-0 and killing concentrations of 3-3 mug./ml. These levels are readily attained in blood and vaginal tissue after oral ingestion of the two imidazole derivatives. Thus, metronidazole has maintained its efficacy since it was first introduced more than a decade ago. The few therapeutic failures with metronidazole and tinidazole are considered to have been caused by pharmacokinetic deficiencies in the patients, or by re-infection.

Treatment of candidal urinary tract infection with nifuratel.

Three patients with candidal urinary tract infections were successfully treated with oral nifuratel, a nitrofuran antimicrobial agent active against yeast and Trichomonas as well as urinary bacterial pathogens. The recommended dose is 400 mg thrice daily for a week. No side effects that could be attributed to the treatment were noted. Minimum ibhibitory concentration determinations for nifuratel against Candida strains of five species showed that 48 out of 59 organisms were inhibited by 50 mg/1 or less, the three strains of Candida species eliminated from our treated patients having MICs of nifuratel in the range of 10-50 mg/1.

[Considerations on the antibiotic activity (M.I.C.) revealed in 247 serotypes of Salmonella]. / Considerazioni sull'attivita' antibiotic (CMI) rilevata su 247 sierotipi di Salmonella

247 strains of Salmonella, isolated in Brescia province duriing 1973-1974 have been typed by serological methods. The MIC has been determined, using the following antibiotics: chloramphenicol, tetracycline HCL, ampicillin, doxycycline, rifampicin, cephazolin, carbenicillin, nifuratel, gentamicin, aminosidine, trimetho-prim-sulphamethoazole, nalidixic acid. The pattern of resistence of the various serotypes is quite constant. The relationship between diffusion and epidermiological factors are discussed.