ABSTRACT
SUMMARY Aims: This study investigated the bioactivity of the crude leaf extract (CLE) and fractions hexane (HX) and ethyl acetate (EtOAc) from Talinum paniculatum alone and in association with fluconazole (FLC) against reference strain and clinical isolates of FLC-resistant Candida albicans. Furthermore, the antioxidant capability, chemical composition of this plant, and the effect's underlying mechanisms were evaluated. Methods: The antifungal activity was evaluated using checkerboard assay to establish the minimum inhibitory (MIC) and minimum microbicidal concen trations (MMC). During FLC and plant products challenges, the reactive oxygen species (ROS) generation (hydroxyl radicals [HO●]) were detected in C. albicans cells using the membrane-permeable fluorescent probes APF and HPF. High-performance liquid chromatography (HPLC) profile, quantitative analysis of antioxidant compounds, and free radical scavenging activity (DPPH assay) tests were performed. Results: The CLE and fractions presented outstanding antifungal activity and selectivity against C. albicans cells but had no synergistic effect's with FLC. The MIC values for CLE and its fractions against C. albicans reference strain were in the order of HX (31.25 µg ml-1) < EtOAc (62.5 μg ml-1) < CLE (500 μg ml-1), and against FLC-resistant C. albicans HX (125 μg ml-1) = EtOAc < CLE (500 μg ml-1). CLE and its fractions had more potent antifungal activities than FLC against the clinical isolates. Moreover, fungicidal effect's for these plant products were demonstrated against FLC-resistant C. albicans, which further conirmed an antifungal potential. Conversely, during association, plant products were shown to cause an increase in FLC MIC anywhere from 2- to 16-fold. FLC exposure led to an increase in the steady-state levels of ROS (HO●) in C. albicans cells. Next, we found that the increases in FLC MICs were owing to action of antioxidants containing-CLE and its fractions in preventing FLC-induced ROS-mediated growth inhibition of C. albicans. Conclusion: T. paniculatum can be a source of bioactive compounds with antifungal potential. However, because of the common use of its edible leaf, caution is advised during therapy with FLC (since it can decrease FLC susceptibility).
RESUMEN Objetivos: este estudio investigó la bioactividad del extracto de hoja en bruto (EHB) y las fracciones hexano (HX) y acetato de etilo (AcOEt) de Talinum paniculatum solo y en asociación con fluconazol (FLC) contra cepas de referencia y aislados clínicos de Candida albicans resistente a FLC. Además, evaluó la capacidad antioxidante, la composición química de esta planta y los mecanismos subyacentes del efecto fungicida. Métodos: la actividad antifúngica se evaluó mediante microdilución en caldo para establecer las concentraciones inhibitorias mínimas (CIM) y microbicidas mínimas (CMM). Durante el tratamiento con FLC y productos vegetales se detectó la generación de especies reactivas de oxígeno (ERO) (radicales hidroxilo [HO●]) en células de C. albicans utilizando las sondas fluorescentes permeables a la membrana APF y HPF. El perfil de cromatografía líquida de alta resolución (CLAR), el análisis cuantitativo de compuestos antioxidantes y el ensayo DPPH fueron evaluados. Resultados: el EHB y las fracciones presentaron una excelente actividad antifúngica y selectividad contra las células de C. albicans, pero no tuvieron efectos sinérgicos con FLC. Los valores de CIM para EHB y sus fracciones contra la cepa referencia de C. albicans fueron del orden de: HX (31,25 μg ml-1) < AcOEt (62,5 μg ml-1) < EHB (500 μg ml-1), y contra C. albicans resistente a FLC: HX (125 μg ml-1)= AcOEt < EHB (500 µg ml-1). EHB y sus fracciones fueron más potentes antifúngicos que FLC contra los aislados clínicos. Además, estos productos vegetales tienen efectos fungicidas contra C. albicans resistentes a FLC, esto conirmó el potencial antifúngico. Por el contrario, durante la asociación se demostró que los productos vegetales causan un aumento en la CIM de FLC de 2 a 16 veces. La exposición a FLC aumentó los niveles de ERO (HO●) en las células de C. albicans. Los aumentos en las CIM de FLC se debieron a la acción de los antioxidantes presentes en EHB y sus fracciones para prevenir la inhibición del crecimiento mediada por ERO inducida por FLC en C. albicans. Conclusión: T. paniculatum puede ser una fuente de compuestos bioactivos con potencial antifúngico. Sin embargo, debido al uso común de su hoja comestible, se recomienda usarla con precaución durante la terapia con FLC (ya que puede disminuir la susceptibilidad a FLC).
ABSTRACT
Oxidative stress is an important risk factor for cardiovascular disease and death in hemodialysis (HD) patients. However, whether biochemical and nutritional markers might be useful to stratify HD patients according to the risk of oxidative damage remains unclear. We investigated whether low-cost and easily available parameters such as the profile of nutrients intake, nutritional status, and antioxidant defenses can predict lipid and protein oxidation in HD patients. Forty-nine HD patients (women = 20, men = 29), ranging from 18 to 65 years of age (73.5%) were submitted to biochemical and nutritional analysis. At least 93.9% of HD patients had malnutrition. A patient's stratification according to nutritional risk was highly coherent with anthropometric parameters and nutrients intake, which were complementarily used as markers of malnutrition. Nutritional stratification was unable to reveal differences in the oxidative status. On the other hand, carbohydrate and zinc intake, serum zinc (Zn), glutathione peroxidase (GPx) activity, total antioxidant capacity (TAC), and nonprotein antioxidants (npAC) in serum were predictive markers of lipid (R 2 = 0.588, P < 0.001) and protein (R 2 = 0.581, P < 0.001) oxidation. Interestingly, GPx activity, TAC, and npAC exhibited good (>80% < 90%) or excellent (>90%) accuracy to estimate lipid oxidation (P ≤ 0.01). Regarding the prediction of protein oxidation, GPx activity and TAC presented regular accuracy (>70% < 80%), and Zn serum levels exhibited good sensitivity (P ≤ 0.01). Herein, we provided evidence that clinical characteristics relevant to predict different levels of lipid and protein oxidation in HD patients can be easily obtained, during routine hospital visits by means of the combined analyses of biochemical and nutritional parameters.
Subject(s)
Kidney Failure, Chronic/blood , Adolescent , Adult , Aged , Antioxidants/metabolism , Biomarkers/blood , Creatinine/blood , Energy Intake/physiology , Female , Hemoglobins/metabolism , Humans , Male , Middle Aged , Nutritional Status , Oxidation-Reduction , Oxidative Stress/physiology , Renal Dialysis , Urea/blood , Young Adult , Zinc/bloodABSTRACT
AIM OF THE STUDY: Averrhoa carambola L. (Oxalidaceae) leaves are used in Brazilian traditional medicine to treat hypertension. This study was conducted to evaluate the hypotensive effect of the aqueous extract of Averrhoa carambola (AEAc) and its underlying mechanisms in the isolated rat aorta. MATERIALS AND METHODS: The effect of AEAc on the mean arterial pressure (MAP) was determined in vivo in anesthetized rats. In vitro, thoracic aortic rings were isolated and suspended in organ baths, and the effects of AEAc were studied by means of isometric tension recording experiments. In HPLC analysis, the fingerprint chromatogram of AEAc was established. RESULTS: In normotensive rats, AEAc (12.5-50.0 mg/kg, i.v.) induced dose-dependent hypotension. In vitro, AEAc caused a depression in the E(max) response to phenylephrine without a change in sensibility. Also, in a depolarized Ca(2+)-free medium, AEAc inhibited CaCl(2)-induced contractions and caused a concentration-dependent rightward shift of the response curves, indicating that AEAc inhibited the contractile mechanisms involving extracellular Ca(2+) influx. CONCLUSIONS: These results demonstrate the hypotensive effects of AEAc, and these effects may, in part, be due to the inhibition of Ca(2+), which supports previous claims of its traditional use.
