Purple pigment from Peltogyne mexicana heartwood as a potential colorant for food.

ABSTRACT: Peltogyne mexicana heartwood might be a novel purple pigment source. The results of the present study demonstrate that the purple pigment is an important source of phenolic compounds (698.22 ± 2.99 mg GAE/g) and flavonoids (48.01 ± 0.51 mg EPE/g). UV-Vis spectrum and color parameters (L* a* b*) showed that purple pigment has different shades of purple-red (H° value 19.32 ± 0.02 in methanol and 22.85 ± 0.01 in ethanol) depending on the solvent and the pH. Also, the purple pigment did not exhibit acute oral toxicity at a single dose (2000 mg/kg body weight). No mutagenicity was observed in the Ames test with three Salmonella typhimurium strains. The purple pigment exhibited considerable coloring properties with a wider range of citric acid-dependent color hues in gelatin (H° from 280.3 to 319.9 and from 68.0 to 88.1), and higher color intensity than commercial anthocyanin. Minor variations in the hue were found in yogurt, for purple pigment with H° values from 317.5 to 315.0, and commercial anthocyanin from 82.6 to 88.7 and 276.9 to 295.5. However, purple pigment required lower concentrations to achieve superior effects. For gelatin and yogurt samples, similar variations in the color parameters L*, a*, b*, and pigment degradation were observed for purple pigment and commercial anthocyanin in the stability assay.

Antimutagenic activity of vitamin B1 against damages induced by chemical and physical mutagens in Salmonella typhimurium and Escherichia coli.

Thiamine (vitamin B1) is an essential nutrient acting mainly as an enzymatic cofactor on diverse cell processes. It has been reported that vitamin B1 has a significant role in the signaling pathways related to the response to adverse environmental conditions (chemical and physical). The objectives of this study were to evaluate the antimutagenic potential of vitamin B1 in front of DNA-alkylating agents in the presence/absence of ogt and ada repairing genes in Salmonella typhimurium strains and against damage induced by ultraviolet light type C in Escherichia coli strains mutated at the uvrABC system and recBCD enzymes. For S. typhimurium, an antimutagenesis test (Ames test) was performed using strains deficient in one or both genes (YG7100 ada-/ogt+, YG7104 ada+/ogt-, YG7108 ada-/ogt-). For E. coli, mutated strains (K-12 derived strains Hfr H180 uvrB+/recA+, W3110 uvrB+/recA- and ATCC®8739 uvrB-/recA+) were exposed to UV-C light at different time intervals, with and without vitamin B1. Our results showed that thiamine is an antimutagen against methyl-N-nitro-N-nitrosoguanidine or ethyl-N-nitro-N-nitrosoguanidine only when the ogt gene is present. While for E. coli, the presence of vitamin B1 increased the survival rate, implying an antimutagenesis independent of uvrABC repairing system and recBCD enzymes.

Antimycotic Activity and Genotoxic Evaluation of Citrus sinensis and Citrus latifolia Essential Oils.

The aim of this study was to evaluate the antifungal activity of essential oils (EOs) of Citrus sinensis (C. sinensis) and Citrus latifolia (C. latifolia) against five Candida species: Candida albicans, Candida tropicalis, Candida glabrata, Candida lusitaniae and Candida guilliermondii; and perform its genotoxic evaluation. The EOs of C. sinensis and C. latifolia were obtained from the peel by hydro-distillation. The major components determined by GC-MS were in C. sinensis, d-limonene (96%) and α-myrcene (2.79%); and in C. latifolia, d-limonene (51.64%), ß-thujene (14.85%), ß-pinene (12.79%) and γ-terpinene (12.8%). Antifungal properties were studied by agar diffusion method, where C. sinensis presented low activity and C. latifolia essential oil was effective to inhibit growing of C. lusitaniae and C. guilliermondii with IC50 of 6.90 and 2.92 µg respectively. The minimum inhibitory concentrations (MIC) for C. sinensis were in a range of 0.42-3.71 µg and for C. latifolia of 0.22-1.30 µg. Genotoxic evaluation was done by Ames test where none of the oils induced point mutations. Flow cytometry was used to measure toxicity in human oral epithelial cells, C. sinensis was not cytotoxic and C. latifolia was toxic at 21.8 µg. These properties might bestow different odontological applications to each essential oil.

In vitro and in vivo antifungal activity, liver profile test, and mutagenic activity of five plants used in traditional Mexican medicine

Berberis hartwegii Benth., Berberidaceae, Hamelia patens Jacq., Rubiaceae, Dendropanax arboreus (L.) Decne & Planch., Araliaceae, Erythrina herbacea L., Fabaceae, and Zanthoxylum caribaeum Lam., Rutaceae, acetone extracts were selected on the basis of their use in traditional Mexican medicine to treat scabies or skin diseases. Anti-dermatophyte activity in vitro was evaluated using the agar dilution assay, and the therapeutic efficacy of B. hartwegii and Z. caribaeum were tested against experimental tinea pedis. The infected animals were treated intragastrically daily for seven days with 2.5 and 5 mg/kg of acetone extracts. The acetone extract of H. patens exhibited 100% growth inhibition against T. mentagrophytes and E. floccosum at 100.0 and 50.0 µg/ml, respectively, and B. hartwegii inhibited growth of M. canis and T. mentagrophytes at 100.0 µg/ml. Effective treatments with 2.5 mg/kg of Z. caribaeum and B. hartwegii extract were comparable with 1 mg/kg of clotrimazole in mice. Liver profile tests and histological analyses did not exhibit any signs of toxicity and the Ames test indicated that both extracts were safe when evaluated in strains TA98, TA100 and TA102. Our results suggest the potential for the future development of new antifungal drugs from B. hartwegii or Z. caribaeum.

Mutagenic and antimutagenic effects of Heterotheca inuloides.

The antioxidant and hepatoprotective effects of Heterotheca inuloides have been reported before, nevertheless its use as a possible chemopreventive agent has not been documented. The aim of this study was to evaluate the mutagenic and antimutagenic activities of H. inuloides extracts using the Ames test. Both, the methanolic and acetonic extracts, were mutagenic in the TA98 but not in TA100 or TA102 strains. On the other hand, the methanolic extract reduced the mutagenicity of norfloxacin, benzo[a]pyrene and 2-aminoanthracene. Quercetin, one of the main components in the methanolic extract, also presented a mutagenic/antimutagenic dual effect and is an inhibitor of Cytochrome P450 (CYP) 1A. The antigenotoxic properties of H. inuloides could be due to the antioxidant properties previously reported and to its CYP inhibitory effect mediated by quercetin. Further studies with in vivo systems will afford information about H. inuloides beneficial and detrimental properties.

Antimutagenicity of Methanolic Extracts from Anemopsis californica in Relation to Their Antioxidant Activity.

Anemopsis californica has been used empirically to treat infectious diseases. However, there are no antimutagenic evaluation reports on this plant. The present study evaluated the antioxidant activity in relation to the mutagenic and antimutagenic activity properties of leaf (LME) and stem (SME) methanolic extracts of A. californica collected in the central Mexican state of Querétaro. Antioxidant properties and total phenols of extracts were evaluated using DPPH (1,1-diphenyl-2-picrylhydrazyl) and Folin-Ciocalteu methods, respectively. Mutagenicity was evaluated using the Ames test employing Salmonella enterica serovar Typhimurium strains (TA98, TA100, and TA102), with and without an aroclor 1254 (S9 mixture). Antimutagenesis was performed against mutations induced on the Ames test with MNNG, 2AA, or 4NQO. SME presented the highest antioxidant capacity and total phenolic content. None of the extracts exhibited mutagenicity in the Ames test. The extracts produced a significant reduction in 2AA-induced mutations in S. typhimurium TA98. In both extracts, mutagenesis induced by 4NQO or methyl-N'-nitro-N-nitrosoguanidine (MNNG) was reduced only if the exposure of strains was <10 µg/Petri dish. A. californca antioxidant properties and its capacity to reduce point mutations render it suitable to enhance medical cancer treatments. The significant effect against antimutagenic 2AA suggests that their consumption would provide protection against carcinogenic polycyclic aromatic compounds.

Effects of Agave tequilana fructans with different degree of polymerization profiles on the body weight, blood lipids and count of fecal Lactobacilli/Bifidobacteria in obese mice.

Fructans are dietary fibers with beneficial effects on the gastrointestinal physiology and offer a promising approach for the treatment of some metabolic disorders associated with obesity. In vitro and in vivo studies were developed to test the safety of fructans obtained from Agave tequilana Weber var. azul. Additionally, an in vivo experiment using a diet-induced obesity model was performed to compare the effect of agave fructans with different degree of polymerization (DP) profiles: agave fructans with DP > 10 (LcF), agave FOS with DP < 10 (ScF), and agave fructans with and without demineralization (dTF, TF) versus commercial chicory fructans (OraftiSynergy1™) on the body weight change, fat, total cholesterol, triglycerides and count of fecal Lactobacillus spp. and Bifidobacterium spp. Results showed that A. tequilana fructans were not mutagenic and were safe even at a dose of 5 g per kg b.w. Obese mice that received ScF showed a significant decrease in body weight gain, fat tissue and total cholesterol without increasing the count of fecal Bifidobacteria. Whereas, obese mice that received LcF and TF showed decreased triglycerides and an increased count of fecal Bifidobacteria. Interestingly, although obese mice that received dTF did not show changes in body weight gain, fat tissue, total cholesterol or triglycerides, they showed an increase in the count of Bifidobacteria. These results demonstrate that both the degree of polymerization and the demineralization process can influence the biological activity of agave fructans.

Antimutagenic properties of affinin isolated from Heliopsis longipes extract.

CONTEXT: Heliopsis longipes (A. Gray) Blake (Asteraceae), commonly known in Mexico as "chilcuage" or "chilcuan", is widely used as an analgesic and anesthetic agent. Affinin, the major metabolite of this plant, and the ethanol extract of the plant have shown antinociceptive properties in mice. H. longipes plant produces a complex mixture of antioxidant chlorophylls and polyamines as well as a number of possible antimutagens. OBJECTIVE: The current study evaluated the potential utilization of the natural product affinin isolated from H. longipes ethanol extract as an antimutagenic and possibly anticarcinogenic agent. MATERIALS AND METHODS: The Ames assay was used to assess the mutagenic properties of affinin (12.5, 25 and 50 µg/plate) that was added to several mutagens with or without S9 metabolic activation in Salmonella typhimurium (TA98, TA100 and TA102 strains). RESULTS: Heliopsis longipes extract and affinin were not toxic as a reduction in the number of His⁺ revertant bacteria colonies. Affinin (25 and 50 µg/plate) significantly reduced the frameshift mutations that were generated by 2-aminoanthracene (2AA) (40%) and reduced the oxidative DNA damage generated by norfloxacin (NOR) (37-50%). Affinin possessed antioxidant properties that were able to reduce 2AA- and NOR-induced mutations in S. typhimurium TA98 and TA102, respectively. DISCUSSION AND CONCLUSION: Affinin, the principal metabolite of H. longipes, is not mutagenic and possesses antimutagenic activity. These plants are currently used to treat some pain symptoms in Mexico; and antimutagen activity determined could be important to treat some pain symptoms related to antiradical activity.

Antimutagenic evaluation of vitamins B1, B6 and B12 in vitro and in vivo, with the Ames test.

The aim of this work is to evaluate vitamins B antimutagenic effect against alkylatings methyl-N-nitro-N-nitrosoguanidine (MNNG), ethyl-N-nitro-N'- nitrosoguanidine (ENNG), frameshift mutagens 2-aminoanthracene (2AA) and 2-acetyl-amino-fluorene (2AF) and ROS-generating antibiotics norfloxacin (NOR) and nalidixic acid (NLX), using the in vitro Ames test. In vivo antimutagenesis studies were performed against urinary mutagens induced by NOR (70 mg/kg) or NLX (100 mg/kg) in CD1 mice. Vitamin B1 was antimutagenic against alkylatings MNNG (P<0.05) or ENNG (P<0.001). In fact as per the results observed during the current study, none of the vitamins reduced mutagenesis caused by frameshift mutagens. All of them reduced mutagenesis of NOR or NLX (P<0.001). In vivo studies showed that vitamins B1 and B6 (10 or 100 mg/kg) reduced urinary mutagens from NOR (P<0.001) or NLX (P<0.02) either free or ß-glucoronidase-conjugates. None of the studied samples were toxic for the employed antimutagenic system. Vitamin B12 (4 mg/kg) reduced urinary mutagens of NOR or NLX (P<0.02). Vitamins B inhibited DNA mutations induced by ROS generated by NLX or NOR, both in vitro and in vivo. Vitamin B1is antimutagenic against mutations induced by the alkylating MNNG or ENNG. Based on the observations, employment of vitamins B in vivo can be a promising alternative to reduce genotoxic risk exposure to ROS.

Antimutagenicity mechanisms of the Rhoeo discolor ethanolic extract.

INTRODUCTION: Rhoeo discolor, a medical plant from Mexico, is known to be an antioxidant and chemoprotective antimutagen. Rhoeo discolor ethanolic extract (EERD) is a complex mixture, so in this study its antimutagenic mechanisms were further evaluated. MATERIAL AND METHODS: Employing Ames test, with uvrB- and uvrB+ strains, its antimutagenic activity against frameshift mutagens 2-amino-anthracene (AA), and 2 amino-fluorene (AF), alkylating: methyl-N'-nitro-N-nitrosoguanidine (MNNG) and ethyl-N'-nitro-N-nitrosoguanidine (ENNG) and mitomycin C were evaluated. Induction of ogt, alkyl-DNA-glycosylases were studied with Salmonella typhimurium strains deficient in ada and ogt genes (YG7100 ada-/ogt+ YG7104 ada+/ogt-, G7108 ada-/ogt-). RESULTS: EERD, was not antimutagenic against AA or AF on S. typhimurium TA98 neither in UTH8413 uvrB+ strains. It significantly reduced mutations induced by Mitomycin C on strain TA102. EERD was antimutagenic to mutations induced by alkylating compounds on S. typhimurium TA100 or UTH8414 uvrB+. This antimutagenic effect was not observed on strains lacking ogt gene. CONCLUSIONS: EERD, did not affect CYP450 in vitro microsomal activation of AF or AA, on the Ames test, neither improved DNA uvrB excision repair system. EERD reduced oxidative damages on strain TA102, caused by Mitomycin C. This plant extract might be used to avoid DNA damage by alkylation, corrected mainly alkylguanine transferase protein encoded by ogt gene.

Prospective study of urinary tract infection surveillance after kidney transplantation.

BACKGROUND: Urinary tract infection (UTI) remains one of the main complications after kidney transplantation and it has serious consequences. METHODS: Fifty-two patients with kidney transplantation were evaluated for UTI at 3-145 days (mean 40.0 days) after surgery.. Forty-two received a graft from a live donor and 10 from a deceased donor. There were 22 female and 30 male patients, aged 11-47 years. Microscopic examinations, leukocyte esterase stick, and urinary culture were performed every third day and weekly after hospitalization. A positive culture was consider when patients presented bacterial counts up to 105 counts. RESULTS: UTI developed in 19/52 (37%) patients at 3-75 days (mean 19.5 days after transplantation. Recurrent infection was observed in 7/52 (13.4%) patients at days 17-65. UTI was more frequent in patients who received deceased grafts compared with live grafts (7/10, 70% vs. 12/42, 28%; p < 0.007). Female patients were more susceptible than male (11/22, 50% vs. 8/22, 36.35%; p < 0.042). Five-year survival rate was 94.5% (49/52 patients). Kidney Graft exit update is 47/52 (90.2%), and there were no significant differences between graft rejection and UTI (p = 0.2518). Isolated bacteria were Escherichia coli (31.5%), Candida albicans (21.0%) and Enterococcus spp. (10.5%), followed by Pseudomonas aeruginosa, Klebsiella pneumoniae, Morganella morganii, Enterobacter cloacae and Micrococcus spp. Secondary infections were produced by (7/19, 36.8%). Enterococcus spp. (57%), E. coli (28%) and Micrococcus spp. (14.2%). Antibiotic resistance was 22% for ciprofloxacin and 33% for ampicillin. Therapeutic alternatives were aztreonam, trimethoprim-sulfamethoxazole, netilmicin and fosfomycin. CONCLUSIONS: Surveillance of UTI for the first 3 months is a good option for improving quality of life of kidney transplantation patients and the exit of graft function especially for female patients and those receiving deceased grafts. Antibiograms provided a good therapeutic alternative to patients who presented with UTIs after receiving a kidney allograft.

[Benefits of Affirm VPIII and L-PAP in the diagnosis of bacterial vaginosis]. / Utilidad del sistema Affirm VPIII y de la prueba L-Pap para el diagnóstico de vaginosis bacteriana.

INTRODUCTION: Bacterial vaginosis is a syndrome occurring in women of reproductive age, characterized by abnormal vaginal discharge and associated with gynecological and obstetric problems during pregnancy. AIM: This study assesses the value of proline aminopeptidase (L-Pap) detection and DNA hybridization with the Affirm VPIII microbial identification test, as analytical tools for the diagnosis of bacterial vaginosis. MATERIAL AND METHODS: Vaginal secretions from 406 women were collected and analyzed to investigate bacterial vaginosis with the Affirm VPIII commercial kit and the L-Pap reaction. The criteria of Nugent et al, and Amsel et al. were used to characterize patients with bacterial vaginosis syndrome. Results were analyzed with a 2 x 2 contingency table and evaluated by the chi-square test, at a significance level of P < 0.05. RESULTS: L-Pap showed a sensitivity of 92.2%, specificity of 93.4%, PPV of 91.7% and NPV of 93.8%. The Affirm VPIII method had a sensitivity of 91.1%, specificity of 94.7%, PPV of 93.1% and NPV of 93.8%. The diagnostic performance of the two tests showed no statistical differences. CONCLUSION. L-Pap and Affirm VPIII are both suitable tests for fast, accurate diagnosis of bacterial vaginosis.

Utilidad del sistema Affirm VPIII y de la prueba L-Pap para el diagnóstico de vaginosis bacteriana / Benefits of Affirm VIII and L-PAP in the diagnosis of bacterial vaginosis

INTRODUCCIÓN. La vaginosis bacteriana es un síndrome asociado con secreción vaginal anormal en la mujer en edad reproductiva y se asocia con complicaciones ginecológicas y obstétricas. OBJETIVO. El propósito de este estudio fue determinar que la detección de prolina aminopeptidasa (L-Pap) y la hibridación de ADN son herramientas útiles para el diagnóstico de vaginosis bacteriana. MATERIAL Y MÉTODOS. Se recogieron y analizaron406 muestras de secreción vaginal, para el estudio de vaginosis bacteriana usando el sistema comercial Affirm VPIII y la prueba L-Pap. Como método estándar se utilizó la combinación de la puntuación de Nugent y los criterios de Amsel et al. Los resultados se analizaron usando la tabla de contingencia de 2 × 2 y la prueba de chi al cuadrado con un nivel de significancia de p < 0,05.RESULTADOS. La L-Pap exhibió una sensibilidad del 92,2%,una especificidad del 93,4%, un valor predictivo positivo(VPP) del 91,7% y un valor predictivo negativo (VPN) del 93,8%. La prueba comercial de hibridación de ADN mostró una sensibilidad del 91,1%, una especificidad del 94,7%, un VPP del 93,1% y un VPN del 93,8%. Ambas pruebas ofrecieron resultados sin diferencias estadísticamente significativas (AU)

INTRODUCTION. Bacterial vaginosis is a syndrome occurring in women of reproductive age, characterized by abnormal vaginal discharge and associated with gynecological and obstetric problems during pregnancy. AIM. This study assesses the value of prolineaminopeptidase (L-Pap) detection and DNA hybridization with the Affirm VPIII microbial identification test, as analytical tools for the diagnosis of bacterial vaginosis. MATERIAL AND METHODS. Vaginal secretions from 406 women were collected and analyzed to investigate bacterial vaginosis with the Affirm VPIII commercial kit and the L-Pap reaction. The criteria of Nugent et al, and Amselet al. were used to characterize patients with bacterial vaginosis syndrome. Results were analyzed with a2 × 2 contingency table and evaluated by the chi-square test, at a significance level of P < 0.05.RESULTS. L-Pap showed a sensitivity of 92.2%, specificity of 93.4%, PPV of 91.7% and NPV of 93.8%. The Affirm VPIII method had a sensitivity of 91.1%, specificity of 94.7%,PPV of 93.1% and NPV of 93.8%. The diagnostic performance of the two tests showed no statistical differences. CONCLUSION. L-Pap and Affirm VPIII are both suitable tests for fast, accurate diagnosis of bacterial vaginosis (AU)

Acute toxicity and mutagenic activity of Mexican plants used in traditional medicine.

The present work was undertaken to determine safety parameters of selected Mexican medicinal plants chosen on the basis of their frequency of medicinal use and commercial importance. The medicinal herbs included Amphipteryngium adstringens, Hintonia standleyana, Hintonia latiflora, Piper sanctum, Haemathoxylon brasiletto, Iostephane heterophylla, Valeriana procera, Arracacia tolucensis, Brickellia veronicaefolia, Scaphyglottis livida, Exostema caribaeum, Hippocratea excelsa, Ligusticum porteri, Poliomintha longiflora and Gnaphalium sp. In the acute toxicity studies in mice performed according to the Lorke procedure, Exostema caribaeum, Hippocratea excelsa, Ligusticum porteri and Poliomintha longiflora were the most toxic with LD(50) values between 1085 and 2mg/kg. The Ames test revealed that Gnaphalium sp. and Valeriana procera extracts induced mutations of S. typhimurium TA98 with or without the S9 microsomal fraction, and TA100 in the presence of the enzymatic fraction, respectively. The tincture of Valeriana procera, however, was non-mutagenic. Finally, in the Artemia salina lethality test Brickellia veronicaefolia, Arracacia tolucensis, Poliomintha longiflora and Piper sanctum caused significant mortality of the crustacean larvae with LC(50) in the range of 37-227 microg/mL.

[Identification of Candida species causing vaginitis in Mexican patients]. / Identificación de especies de Candida causantes de vaginitis en la población mexicana.

INTRODUCTION: The increasing frequency of candidiasis due Candida spp. other than C. albicans suggests that these organisms may also have emerged as a cause of vaginitis. OBJECTIVE: The aim of this study was to investigate the species of Candida most frequently isolated from Mexican patients with vaginal candidiasis. MATERIAL AND METHODS: A total of 631 isolates of Candida were identified by the API 20C system and standard bacteriological tests. RESULTS: The most frequently identified species were C. albicans (39.0%), C. glabrata (35.9%), and C. tropicalis (16.2%). CONCLUSIONS: The results of this study show that in addition to C. albicans, C. glabrata and C. tropicalis can also be considered important vaginal pathogens in Mexican patients.

Identificación de especies de Candida causantes de vaginitis en la población mexicana / Identification of Candida species causing vaginitis in Mexican patients

Introducción. El incremento de las candidiasis producidas por Candida no albicans puede sugerir la creciente importancia de estos microorganismos como causa de vaginitis. Objetivo. Conocer las especies de Candida aisladas más frecuentemente en mujeres mexicanas con candidiasis vaginal. Material y métodos. Empleando el sistema API 20C y otras pruebas convencionales se identificaron 631 especies de Candida. Resultados. Las especies más frecuentemente identificadas fueron las siguientes: C. albicans 39,0%, C. glabrata 35,9% y C. tropicalis 16,2%. Conclusiones. Los resultados de este estudio indican que, en pacientes mexicanas, además de C. albicans, C. glabrata y C. tropicalis deben considerarse también patógenos vaginales importantes (AU)

Introduction. The increasing frequency of candidiasis due Candida spp. other than C. albicans suggests that these organisms may also have emerged as a cause of vaginitis. Objective. The aim of this study was to investigate the species of Candida most frequently isolated from Mexican patients with vaginal candidiasis. Material and methods. A total of 631 isolates of Candida were identified by the API 20C system and standard bacteriological tests. Results. The most frequently identified species were C. albicans (39.0%), C. glabrata (35.9%), and C. tropicalis (16.2%). Conclusions. The results of this study show that in addition to C. albicans, C. glabrata and C. tropicalis can also be considered important vaginal pathogens in Mexican patients (AU)

A new test of disk-diffusion to help in staphylococci identification.

A modified carbohydrate fermentation test (MCFT) of disk-diffusion assay was performed using a peptone-free agar medium, in order to improve the identification of clinical staphylococci species. Results were compared with the standard method of carbohydrate fermentation in tubes (SCFT) containing methyl red broth. MCFT was able to identify correctly 12 different species of staphylococci from the ATCC collection and 646 clinical isolates. MCFT showed sensitivity between 91.6% and 100% and specificity between 99.6% and 100%, for the different carbohydrates studied. MCFT could replace the SCFT, with the evident advantage of reducing time for materials preparation. The method presented herein is easy to perform in clinical or research microbiology laboratories, because it can differentiate species of staphylococci.

Antiamoebic and toxicity studies of a carbamic acid derivative and its therapeutic effect in a hamster model of hepatic amoebiasis.

Amoebiasis is an important public health problem in developing countries. Entamoeba histolytica, the causative agent of amoebiasis, may develop resistance to nitroimidazoles, a group of drugs considered to be the most effective against this parasitic disease. Therefore, research on new drugs for the treatment of this common infection still constitutes an important therapeutic demand. In the present study we determined the effects of a carbamate derivative, ethyl 4-chlorophenylcarbamate (C4), on trophozoites of E. histolytica strain HM-1:IMSS. C4 was subject to various toxicity tests, including the determination of mutagenicity for bacterial DNA and changes in the enzymatic activities of eukaryotic cells. Genotoxicity studies were performed by the mutagenicity Ames test (plate incorporation and preincubation methods) with Salmonella enterica serovar Typhimurium, with or without metabolic activation produced by the S9 fraction of rat liver. C4 toxicity studies were performed by measuring enzymatic activity in eukaryotic cells by the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide-formazan test with Fischer 344 rat hepatocytes. C4 did not induce either frame-shift mutations in S. enterica serovar Typhimurium TA97 or TA98 or base pair substitutions in strains TA100 and TA102. The compound was not toxic for cultured rat hepatic cells. Trophozoites treated with 100 microg of C4 per ml were inhibited 97.88% at 48 h of culture; moreover, damage to the amoebae was also confirmed by electron microscopy. The antiamoebic activity of C4 was evaluated by using an in vivo model of amoebic liver abscess in hamsters. Doses of 75 and 100 mg/100 g of body weight reduced the extent of the amoebic liver abscess by 84 and 94%, respectively. These results justify further studies to clearly validate whether C4 is a new suitable antiamoebic drug.