Phytochemistry Profile, Antimicrobial and Antitumor Potential of the Methanolic Extract of Tabernaemontana catharinensis A DC and Eragrostis plana NEES.

Natural compounds that have the potential to act as antimicrobials and antitumors are a constant search in the field of pharmacotherapy. Eragrostis plana NEES (Poaceae) is a grass with high allelopathic potential. Allelopathy is associated with compounds generated in the primary and secondary metabolism of the plant, which act to protect it from phytopathogens. Tabernaemontana catharinensis A DC (Apocynaceae), a tree in which its leaves and bark are used for the preparation of extracts and infusions that have anti-inflammatory and antinociceptive effects, is attributed to its phytochemical constitution. The objective of this study was to elucidate the phytochemical constitution, the antibacterial potential, the toxicity against immune system cells, hemolytic potential, and antitumor effect of methanolic extracts of E. plana and T. catharinensis. The phytochemical investigation was carried out using the UHPLC-QTOF MS equipment. The antibacterial activity was tested using the broth microdilution plate assay, against Gram-negative and Gram-positive strains, and cytotoxicity assays were performed on human peripheral blood mononuclear cells (PBMC) and in vitro hemolysis. Antitumor activity was performed against the colon cancer cell line (CT26). Results were expressed as mean and standard deviation and analyzed by ANOVA. p < 0.05 was considered significant. More than 19 possible phytochemical constituents were identified for each plant, with emphasis on phenolic compounds (acids: vanillic, caffeic, and quinic) and alkaloids (alstovenine, rhyncophylline, amezepine, voacangine, and coronaridine). Both extracts showed antibacterial activity at concentrations below 500 µg/mL and were able to decrease the viability of CT26 at concentrations below 2000 µg/mL, without showing cytotoxic effect on PBMCs and in vitro hemolysis at the highest concentration tested. This is the first report of the activity of E. plana and T. catharinensis extracts against colon cancer cell line (CT26). Studies should be carried out to verify possible molecular targets involved in the antitumor effect in vivo.

Measurement of resistance-area product by transcranial Doppler: An alternative tool for cognitive screening in hypertensive on drug treatment?

Introduction: Arterial hypertrophy and remodeling are adaptive responses present in systemic arterial hypertension that can result in silent ischemia and neurodegeneration, compromising brain connections and cognitive performance (CP). However, CP is affected differently over time, so traditional screening methods may become less sensitive in assessing certain cognitive domains. The study aimed to evaluate whether cerebrovascular hemodynamic parameters can serve as a tool for cognitive screening in hypertensive without clinically manifest cognitive decline. Methods: Participants were allocated into groups: non-hypertensive (n = 30) [group 1], hypertensive with systolic blood pressure (SBP) < 140 and diastolic blood pressure (DBP) < 90 mmHg (n = 54) [group 2] and hypertensive with SBP ≥ 140 or DBP ≥ 90 (n = 31) [group 3]. Measurements of blood pressure and middle cerebral artery blood flow velocity were obtained from digital plethysmography and transcranial Doppler. For the cognitive assessment, the Mini Mental State Examination (MMSE), the Montreal Cognitive Assessment (MoCA) and a broad neuropsychological battery were applied. Results: Patients in groups 2 and 3 show no significant differences in most of the clinical-epidemiological variables or pulsatility index (p = 0.361), however compared to group 1 and 2, patients in group 3 had greater resistance-area product [RAP] (1.7 [±0.7] vs. 1.2 [±0.2], p < 0.001). There was a negative correlation between RAP, episodic memory (r = -0.277, p = 0.004) and cognitive processing speed (r = -0.319, p = 0.001). Conclusion: RAP reflects the real cerebrovascular resistance, regardless of the direct action of antihypertensive on the microcirculation, and seems to be a potential alternative tool for cognitive screening in hypertensive.

Phytochemical characterisation, antioxidant capacity, and in vitro toxicity of Richardia brasiliensis gomes crude extracts.

Richardia brasiliensis is a species used in folk medicine and rich in active compounds. In this study, the extracts were submitted to UHPLC-ESI-MS/MS analysis and total polyphenols, tannins, and flavonoids assays. Besides, it was determined its antioxidant capacity, oxidative stress markers and toxicological profile. Fourteen polyphenols were found and, in the dosages, a slight change in the concentrations in each extract was observed. Regarding the antioxidant capacity, the responses were different in the methods used. There was an increase in lipid peroxidation, and NO, however total ROS remained unchanged. The cells remained more than 90% viable and the extracts did not cause damage to single strands of DNA, with the exception of the crude autumn and spring extracts at 500 µg/mL. The results found in this study suggest that extracts are potentially toxic to human leukocyte cells in high concentrations; however, more studies should be performed in different cell lines.

Momordica charantia extract modulates inflammatory response in human lymphocytes via suppression of TNF-a / El extracto de Momordica charantia modula la respuesta inflamatoria en linfocitos humanos a través de la supresión de TNF-a

Introducción: Momordica charantia L. es ampliamente utilizada para consumo y medicina tradicional debido a sus actividades biológicas. Sin embargo, se sabe poco sobre los efectos del melón amargo en las células sanas. Por lo tanto, nuestro objetivo fue evaluar los efectos del extracto de Momordica charantia en linfocitos humanos aislados, especialmente en aspectos inflamatorios, citotóxicos, genotóxicos y mutagénicos. Método : Para ello se preparó un extracto hidroetanólico con frutos y semillas y se procedió a la identificación y cuantificación fitoquímica. Los linfocitos humanos purificados se expusieron a 12,5; 25; 50 μg/mL de extracto de Momordica charantia durante 24 horas y después de este período. Resultados : Los datos mostraron que el extracto de Momordica charantia no indujo citotoxicidad, alteraciones en la frecuencia de micronúcleos, ni actividad de interleucina-6, interleucina-10 ciclooxigenasa-2 y producción de óxido nítrico; sin embargo, causó daño en el ADN y una disminución de TNF-α en las condiciones experimentales y células aplicadas. Conclusiones : Nuestros datos proponen un proceso antiinflamatorio generado por Momordica charantia mediado por la reducción de TNF-α. (AU)

Introduction: Momordica charantia L. is widely used for consumption and traditional medicine due to its biolog-ical activities. Nevertheless, little is known about the effects of bitter melon on healthy cells. Hence, we aimed to evaluate the effects of Momordica charantia extract in human isolated lymphocytes, especially on inflammatory, cytotoxicity, genotoxicity, and mutagenicity aspects. Method: For this, we prepared a hydroethanolic extract with fruits and seeds and proceeded with phytochemical identification and quantification. The human purified lymphocytes were exposed to 12.5, 25, and 50 μg/mL of Mo-mordica charantia extract for 24h and, after this period. Results: The data showed that the Momordica charantia extract did not induce cytotoxicity, micronucleus frequen-cy alterations, or interleukin-6, interleukin-10 cyclooxygenase-2 activity and the production of nitric oxide; however, it caused DNA damage and a decrease of TNF-α under the experimental conditions and cells applied. Conclusions: Our data propose an anti-inflammatory process generated by Momordica charantia mediated by TNF-α reduction. (AU)

Sida tuberculata: In vitro cytotoxicity and in vivo anti-inflammatory effect.

ETHNOPHARMACOLOGICAL RELEVANCE: Sida tuberculata R. E. Fries (Malvaceae) is a pioneer species considered a weed in farm fields in Southern Brazil. Widely distributed in South Brazil, S. tuberculata is popularly used to treat inflammatory conditions. AIMS OF THE STUDY: The current study aimed to assess the in vitro cytotoxic and in vivo anti-inflammatory properties of S. tuberculata. MATERIALS AND METHODS: Initially, extracts obtained from leaves (STLE) and roots (STRE) were submitted to cytotoxicity tests using human leukocytes (non-malignant cell line) and HepG2 and MCF-7 (tumor cell lines). In sequence, anti-inflammatory properties were investigated against carrageenan-induced peritonitis model. RESULTS: In vitro analyses displayed a significant decrease in human leukocytes viability without genotoxic damage. IC50 results from tumor cells presented significant decrease in cell viability, slightly more pronounced for STRE. In addition, STLE significantly inhibited the inflammatory and oxidative parameters (TBARS, NPSH, SOD, MPO activity, cell influx, and cytokines release). CONCLUSION: Our findings indicate S. tuberculata extracts have cytotoxic potential more pronounced on tumor cell lines, as well as leaves extract shows a significant reduction in acute inflammation process, as already reported for Sida genus and specifically for this species.

Assessment of cytotoxicity, genotoxicity, and mutagenicity of the dexchlorpheniramine reference standard and pharmaceutical formula in human peripheral blood mononuclear cells

Abstract Dexchlorpheniramine is a first-generation classical antihistamine, clinically used to treat allergies. The main objective of our study was to evaluate the effects of the dexchlorpheniramine reference standard (DCPA Ref. St) and a pharmaceutical formula on DNA in human peripheral blood mononuclear cells (PBMCs). We exposed PBMCs to five different concentrations (0.5, 2.5, 5, 10, and 50 ng/mL) of DCPA Ref. St DCPA Ref. St and pharmaceutical formula in order to evaluate their cytotoxic, genotoxic, and mutagenic potential. The results showed that both dexchlorpheniramine formulations did not affect PBMC viability and CD3+, CD4+, or CD8+ lymphocyte subpopulations. The DCPA Ref. St and pharmaceutical formula neither induced genotoxic or mutagenic effects nor numerical or structural chromosomal alterations in PBMCs after 24 hours of exposure.

Tadalafil and Sildenafil illicit association: Stability- indicating HPLC method, photodegradation kinetic and toxicological studies

Abstract The illicit market of counterfeit medicines containing sildenafil and tadalafil has been causing serious public health problems. Thus, further studies on this illicit association are needed. A stability-indicating HPLC method was developed for simultaneous determination of tadalafil (TAD) and sildenafil (SIL) using a C18 column (250 x 4.6 mm, 5 µm). Detection was achieved at 284 nm, for TAD, and 292 nm, for SIL. The method was considered to be specific, linear, precise, accurate, robust, and sensitive. In the photodegradation kinetic studies, the drugs showed a first-order reaction rate when isolated, and zero-order when associated. Toxicological assays demonstrated that the photodegraded drugs decreased cell viability in compared to non- degraded drugs, suggesting cytotoxic activity. Additional, mutagenic activity was not observed under the tested conditions. Photodegraded drugs, in association, depicted DNA damage index, suggesting genotoxic effects. The obtained results will be able to support the forensic intelligence laboratories, as well as to alert the population about the risk inherent to consuming counterfeit products.

Evaluation In Vitro of Toxicity of Hydroalcoholic Extract of Leaves and Roots from Yacon (Smallanthus sonchifolius).

Yacon is an Andean plant that has been used in folk medicine for its medicinal properties. The beneficial effects of this plant are possibly due to the high content of phenolic compounds present in its leaves and roots. This study evaluated the in vitro toxicity of the hydroalcoholic extract of leaves and roots from yacon (1, 10, 50, and 100 µg/mL) through cell viability tests, genotoxic and mutagenic activity in leukocytes culture cells; and cytotoxicity and apoptosis cell death (1, 10, 50, 100, and 500 µg/mL) in cell line originally established from the primary mouse embryonic fibroblast cells that were cultured by the designated protocol, so-called 3T3 protocol "3-day transfer, inoculum 3 × 105 cells" (3T3 cell line). No mutagenic and cytotoxic activities were observed in leukocyte cultures. Cytotoxic activity was evidenced in the highest concentrations of yacon leaf extract (50 and 100 µg/mL), whereas all concentrations tested with yacon leaf extract there was induction for apoptosis in the 3T3 cells. Genotoxic potential was observed only at higher doses of leaf (50 and 100 µg/mL) and root (100 µg/mL) extract. These results suggest that yacon leaf at high concentrations may present toxic potential showing concentration-dependent behavior; however, in vivo studies should be performed to validate these results.

Anti-Staphylococcus aureus Methicillin-Resistant (MRSA) activity of a novel 3-Chalcogenyl Indole / Atividade Anti-Staphylococcus aureus Meticilina Resistente (MRSA) de um novo composto 3-Calcogenil Indol

Objective: the development of new drugs against Methicillin-resistant Staphylococcus aureus is a priority to the World Health Organization. So, the objective of this study was to evaluate the antibacterial activity and toxicity of 5-bromo-3-((4-methoxyphenyl) sulfenyl)-1H-indole (3b) against MRSA. Methods: minimum inhibitory concentration (MIC) of 3b was determined against S. aureus ATCC 29213 and 43 clinical isolates. The time-kill assay was performed for 9 isolates. Analysis of variance followed by the post hoc Bonferroni test was used for the statistical tests. Results and conclusions: the MIC50 and MIC90 of 3b were 4 µg.mL-1 and 16 µg.mL-1 respectively. In time-kill assay, the 3b showed bactericidal activity to all evaluated isolates at concentrations of 1xMIC and 2xMIC and the re-growth effect was not observed. About the toxicity tests, 3b has not presented cytotoxicity, mutagenicity, or allergenicity. 3b had particularly good activity against MRSA demonstrating high potential for the development of new antimicrobials products.

Objetivo: o desenvolvimento de novos antimicrobianos contra Staphylococcus aureus resistentes à meticilina (MRSA) é uma prioridade para a Organização Mundial da Saúde. Então, o objetivo desse estudo foi avaliar a atividade antibacteriana e a toxicidade do 5-bromo-3-((4-metoxifenil) sulfenil)-1H-indol (3b) contra MRSA. Métodos: a concentração inibitória minima de 3b foi determinada contra S. aureus ATCC 29213 e 43 isolados clínicos. O ensaio de curva de morte foi realizado para nove isolados. Análise de variância seguida pelo teste post hoc Bonferroni foi usada para testes estatísticos. Resultados e conclusões: a MIC50 e MIC90 do 3b foi 4 µg.mL-1 e 16 µg.mL-1, respectivamente. No ensaio de curva de morte, o 3b demonstrou atividade bactericida contra todos os isolados avaliados na concentração de 1xMIC e 2xMIC e o recrescimento não foi observado. Em relação aos testes de toxicidade, 3b não apresentou citotoxicidade, mutagenicidade ou alergenicidade. 3b apresentou atividade particularmente interessante contra MRSA, demonstrando alto potencial para o desenvolvimento de novos produtos antimicrobianos.

The use of fructose as a sweetener. Is it a safe alternative for our immune system?

Fructose is a constituent of sucrose and other polymers referred to as inulin or fructans. We can find in cereals, vegetables, and honey. It has the property of being 1.5 times sweeter than sucrose. Our objective was to test this sweetener under and at average concentrations of consumption, evaluating parameters of cytotoxicity, genotoxicity, and immunotoxicity. For this purpose, we made use of lymphocyte cultures and the analysis of their CD4+ and CD8+ subpopulations. Computational methods propose the mechanism of action. Our data showed a reduction in all lymphocyte subfractions evaluated, resulting in a reduction in total lymphocytes, as well as an increase in the DNA damage of cells exposed to fructose. It was possible to propose that fructose modulates gene expression, mainly interfering with the MAPK8, APTX, TUBGCP3, and LST1 genes. Although fructose is used globally as a sweetener, its use should be cautious, as our study points out that it has cytotoxic and genotoxic effects. PRACTICAL APPLICATIONS: Fructose is one of the most sold and used sweeteners in the world. We show here that its use must be restricted and used carefully because it can alter the gene expression and also interfere with cellular and genetic metabolism and may even interfere with the immune response.

Evaluation of cerebral autoregulation performance in patients with arterial hypertension on drug treatment.

Cerebral autoregulation (AR) keeps cerebral blood flow constant despite fluctuations in systemic arterial pressure. The final common AR pathway is made up of vasomotor adjustments of cerebrovascular resistance mediated by arterioles. Structural and functional changes in the arteriolar wall arise with age and systemic arterial hypertension. This study evaluated whether AR is impaired in hypertensive patients and whether this impairment differs with disease control. Three groups of patients were prospectively compared: hypertensive patients under treatment with systolic blood pressure (SBP) <140 and diastolic blood pressure (DBP) <90 mm Hg (n = 54), hypertensive patients under treatment with SBP > 140 or DBP > 90 mm Hg (n = 31), and normotensive volunteers (n = 30). Simultaneous measurements of cerebral blood flow velocity (CBFV) and BP were obtained by digital plethysmography and transcranial Doppler, and the AR index (ARI) was defined according to the step response to spontaneous fluctuations in BP. Compared to the uncontrolled hypertension, the normotensive individuals were younger (age 43.42 ± 11.14, P < .05) and had a lower resistance-area product (1.17 ± 0.24, P < .05), although age and greater arteriolar stiffness did not affect the CBFV mean of hypertensive patients, whether controlled or uncontrolled (62.85 × 58.49 × 58.30 cm/s, P = .29), most likely because their ARIs were not compromised (5.54 × 5.91 × 5.88, P = .6). Hypertensive patients under treatment, regardless of their BP control, have intact AR capacity.

Steviol, the active principle of the stevia sweetener, causes a reduction of the cells of the immunological system even consumed in low concentrations.

AIM: Steviol is a natural diterpenoid glycoside isolated from Stevia rebaudiana Bertoni leaves and widely used as a non-caloric sweetener. In addition to their sweet taste, Steviol glycosides may also have some therapeutic benefits. There are few reports on the cytotoxicity of Steviol in human cells. Our objective was to test this sweetener under and at average concentrations of consumption, evaluating parameters of cytotoxicity, genotoxicity, and immunotoxicity. METHODS: For this purpose, we made use of lymphocyte cultures and the analysis of their CD3+, CD4+, and CD8+ subpopulations. In a complementary way, the mechanism of action is proposed here by computational methods. RESULTS AND CONCLUSION: Our results showed that Steviol reduces the number of lymphocytes due to falls of CD4+, CD8+, and CD4+CD8+ subpopulations. Besides, we observed an increase in the level of DNA damage and a gradual incidence of structural changes in the lymphocyte chromosomal sets. It was possible to propose that Steviol modulates gene expression, mainly interfering with the SESN1, NAP1L1, SOX4, and TREX1 genes. Although Steviol is used globally as a sweetener, its use should be cautious, as our study points out that Steviol has cytotoxic, genotoxic and mutagenic effects in the concentrations and conditions tested in the culture of human lymphocyte cells.

Systemic arterial hypertension and cognition in adults: effects on executive functioning.

BACKGROUND: Central nervous system changes associated to systemic arterial hypertension (SAH) are progressive and may cause negative effects on cognitive performance. The objective of this study was to investigate the relation between SAH and the components of executive functions (EF), inhibitory control (IC), updating and shifting, comparing a control group (without SAH) to patients with SAH, in two levels of severity. METHODS: The protocol included the following tests to evaluate EF components: T.O.V.A. Test (IC), Backward Digit Span from Wechsler Adults Intelligence Scale (WAIS-III), Phonemic and Semantic Verbal Fluency (updating), and Trail Making Test Part B (shifting). RESULTS: A total of 204 participants was included: 56 from the Control Group (CG), 87 SAH stage 1, and 61 SAH stage 2. The groups were not different for age (52.37±12.29) and education (10.98±4.06). As to controlled blood pressure (BP), duration of hypertension treatment and number of drugs, the SAH 2 group had a worse BP control, longer duration of hypertension treatment and use of more drugs when compared to the SAH 1. The findings revealed that patients with more severe hypertension presented worse performance in updating (Backward Digit Span, phonemic and semantics VF) and shifting (Trail Making Test Part B). CONCLUSION: The results suggest that patients with SAH have a significant impairment in EF, more specifically in updating and shifting. Besides that, such damage may be directly proportional to the severity of SAH. It is suggested that future studies include neuroimaging exams to exclude possible cerebrovascular diseases.

Systemic arterial hypertension and cognition in adults: effects on executive functioning / Hipertensão arterial sistêmica e cognição em adultos: efeitos no funcionamento executivo

ABSTRACT Background: Central nervous system changes associated to systemic arterial hypertension (SAH) are progressive and may cause negative effects on cognitive performance. The objective of this study was to investigate the relation between SAH and the components of executive functions (EF), inhibitory control (IC), updating and shifting, comparing a control group (without SAH) to patients with SAH, in two levels of severity. Methods: The protocol included the following tests to evaluate EF components: T.O.V.A. Test (IC), Backward Digit Span from Wechsler Adults Intelligence Scale (WAIS-III), Phonemic and Semantic Verbal Fluency (updating), and Trail Making Test Part B (shifting). Results: A total of 204 participants was included: 56 from the Control Group (CG), 87 SAH stage 1, and 61 SAH stage 2. The groups were not different for age (52.37±12.29) and education (10.98±4.06). As to controlled blood pressure (BP), duration of hypertension treatment and number of drugs, the SAH 2 group had a worse BP control, longer duration of hypertension treatment and use of more drugs when compared to the SAH 1. The findings revealed that patients with more severe hypertension presented worse performance in updating (Backward Digit Span, phonemic and semantics VF) and shifting (Trail Making Test Part B). Conclusion: The results suggest that patients with SAH have a significant impairment in EF, more specifically in updating and shifting. Besides that, such damage may be directly proportional to the severity of SAH. It is suggested that future studies include neuroimaging exams to exclude possible cerebrovascular diseases.

RESUMO Introdução: As alterações do sistema nervoso central associadas à hipertensão arterial sistêmica (HAS) são progressivas e podem ocasionar efeitos negativos no desempenho cognitivo. O objetivo deste estudo foi investigar a relação entre a HAS e os componentes das funções executivas (FE), controle inibitório (CI), atualização e alternância, comparando um grupo controle (sem HAS) a pacientes com HAS, em dois níveis de gravidade. Métodos: O protocolo incluiu os seguintes testes para avaliar os componentes das FE: T.O.V.A. Test (CI), Dígitos Ordem Indireta da Escala de Inteligência Wechsler para Adultos (Wechsler Adults Intelligence Scale - WAIS-III), Fluência Verbal fonêmica e semântica (atualização) e Teste de Trilhas parte B (alternância). Resultados: Foram incluídos 204 participantes, sendo 56 do Grupo Controle (GC), 87 HAS estágio 1 (HAS 1) e 61 de HAS estágio 2 (HAS 2). Os grupos não foram diferentes em relação à idade (52,37±12,29) e escolaridade (10,98±4,06). Em relação à pressão arterial (PA) controlada, tempo de tratamento da HAS e número de medicações, o grupo HAS 2 apresentou pior controle de PA, mais tempo de tratamento da HAS e uso de maior número de medicações quando comparado ao grupo HAS 1. Os achados revelaram que os pacientes com HAS em estágio mais grave apresentaram pior desempenho nos testes de alternância (Teste de Trilhas parte B) e atualização (Dígitos Ordem Indireta, FV fonêmica e semântica). Conclusão: Esses resultados sugerem que pacientes com a HAS possuem prejuízo significativo em FE, especificamente em alternância e atualização, e que esse prejuízo pode ser diretamente proporcional à gravidade da HAS. Sugere-se que, em estudos futuros, incluam-se exames de neuroimagem com o objetivo de excluir possíveis doenças cerebrovasculares.

Sucralose causes non-selective CD4 and CD8 lymphotoxicity via probable regulation of the MAPK8/APTX/EID1 genes: An in vitro/in silico study.

One of the most widely used sweeteners in the world is sucralose. With sweetening power 600 times greater than sucrose, its use grows among those who seek to cut calories. Research shows that when heated, sucralose generates toxic products that attack the organism and interact with DNA. Our objective was to test this sweetener under unheated conditions and at average concentrations of consumption, evaluating parameters of cytotoxicity, genotoxicity, and immunotoxicity. For this purpose, we made use of lymphocyte cultures and the analysis of their CD3+ , CD4+ , and CD8+ subpopulations. In a complementary way, the mechanism of action is proposed here by computational methods. Our results showed that sucralose reduces non-selectively the total lymphocytes due to falls in the levels of the CD4+ , CD8+ , and CD4+ CD8+ subpopulations. We observed an increase in the level of DNA damage and a gradual incidence of structural changes in the lymphocyte chromosomal sets. It was possible to propose that sucralose modulates the gene expression, interfering especially with the MAPK8, APTX, and EID1 genes. This article presents the results of an evidence-based approach to the safety of human health in the use of sucralose. Finally, this study points out that sucralose has cytotoxic, genotoxic, and mutagenic effects in the concentrations and conditions tested in human lymphocyte cell culture.

Fumonisin B1 induces toxicity in human leukocytes at low concentrations: Are computational studies effective to determine biosafety?

Fumonisin B1 is a mycotoxin produced by Fusarium verticillioides and Fusarium proliferatum found in various crops, particularly maize. Besides carcinogenicity, other manifestations have been registered in different animals and in humans. In the case of humans, epidemiological studies have reported high prevalence of esophageal cancer in populations exposed to fumonisins. This study aimed to evaluate the minimum concentration of FB1 capable of inducing cytotoxicity (cell viability test), genotoxicity (comet assay) and mutagenicity (micronucleus) in cultured human leukocytes and to evaluate the effectiveness of in silico tests to predict FB1 toxicity. All concentrations analyzed (200; 100; 50; 5; 0.5; 0.05; 0.005 µg/mL and 300; 30; 3; 1; 0.1; 0.01 fg/mL) except the lowest demonstrated dose-dependent toxicity in all parameters analyzed (p < 0.05 to p < 0.0001). As for predictions, only the Lazar software showed carcinogenicity of FB1 for rats. Thus, it is evident that FB1 is able to induce dose-dependent damage at low concentrations, and that computational tests, although desirable for prediction, are not effective as biological tests to determine toxicity, at least of FB 1 and within the experimental conditions tested.

Validation of an analytical method by high-performance liquid chromatography and microbiological assay, biological safety and in silico toxicity for danofloxacin

Danofloxacin is a veterinary fluoroquinolone used to treat respiratory and gastrointestinal diseases of birds, pigs and cattle. The literature reviewed shows some analytical methods to quantify this fluoroquinolone, but microbiological and biological safety studies are limited. The analytical methods were validated by the Official Codes. The LC-DAD method was developed and validated using an RP-18 column, mobile phase containing a mixture of 0.3% triethylamine (pH 3.0) and acetonitrile (85:15, v/v). The microbiological assay was performed by agar diffusion method (3 x 3) and Staphylococcus epidermidis as a microorganism test. Forced degradation studies were performed in both methods. The minimum inhibitory concentration (MIC) was performed by test microdilution and toxicity studies were evaluated using in silico study, cell proliferation, cell viability test, micronuclei and comet assay. LC and a microbiological assay proved linear, accurate, precise, and robust to quantify danofloxacin, but only the LC method showed selectivity to quantify the drug in the presence of its degradation products. These results demonstrate that the LC method is suitable for stability studies of danofloxacin, but a microbiological assay cannot be used to quantify the drug due to the biological activity of the photoproducts. Ex-vivo cytotoxicity and theoretical and experimental genotoxicity were also observed.

Design, synthesis, and evaluation of novel 2-substituted 1,4-benzenediol library as antimicrobial agents against clinically relevant pathogens.

Development of new antimicrobial agents, capable of combating resistant and multidrug-resistant fungal and bacterial clinical strains, is necessary. This study presents the synthesis and antimicrobial screening of 42 2-substituted-1,4-benzenediols, being 10 novel compounds. In total, 23 compounds showed activity against fungi and/or bacteria. Benzenediol compounds 2, 5, 6, 8, 11, and 12 demonstrated broad spectrum antimicrobial actions, including resistant and multidrug-resistant species of dermatophytes (Trichophyton mentagrophytes), Candida spp. and the ESKAPE panel of bacteria. Minimum inhibitory concentrations of these compounds for fungi and bacterial strains ranged from 25 to 50 µg/ml and 8-128 µg/ml, respectively. The antifungal mechanism of action is related to the fungal cell wall of dermatophytes and membrane disruption to dermatophytes and yeasts, in the presence of compound 8. Specific structural changes, such as widespread thinning along the hyphae and yeast lysis, were observed by scanning electron microscopy. The effects of compound 8 on cell viability are dose-dependent; however they did not cause genotoxicity and mutagenicity in human leukocyte cells nor haemolysis. Moreover, the compounds were identified as nonirritant by the ex-vivo Hen's egg test-chorioallantoic membrane (HET-CAM). The furan-1,4-benzenediol compound 5 showed in vivo efficacy to combat S. aureus infection using embryonated chicken eggs. Therefore, the compounds 8, and 5 are promising as hits for the development of new antimicrobial drugs with reduced toxicity.