Andreas Sebastian Loureiro Mendez

The influence of Bauhinia forficata Link subsp. pruinosa tea on lipid peroxidation and non-protein SH groups in human erythrocytes exposed to high glucose concentrations

ETHNOPHARMACOLOGICAL RELEVANCEnBauhinia forficata (BF) has been traditionally used as tea in folk medicine of Brazil for treatment of Diabetes mellitus (DM).nnnAIM OF THE STUDYnTo evaluate the effects of BF leaf tea on markers of oxidative damage and antioxidant levels in an experimental model of hyperglycemia in human erythrocytes in vitro.nnnMATERIALS AND METHODSnHuman erythrocytes were incubated with high glucose concentrations or glucose and BF tea for 24h and 48h. After incubation lipid peroxidation and non-protein SH levels were analyzed. Moreover, quantification of polyphenols and flavonoids, iron chelating property, scavenging of DPPH, and prevention of lipid peroxidation in isolated lipids were also assessed.nnnRESULTSnA significant amount of polyphenols and flavonoids was observed. The main components found by LC-MS analysis were quercetin-3-O-(2-rhamnosyl) rutinoside, kaempferol-3-O-(2-rhamnosyl) rutinoside, quercetin-3-O-rutinoside and kaempferol-3-O-rutinoside. BF tea presents important antioxidant and chelating properties. Moreover, BF tea was effective to increase non-protein SH levels and reduce lipid peroxidation induced by high glucose concentrations in human erythrocytes.nnnCONCLUSIONnThe antioxidant effects of BF tea could be related to the presence of different phenolic and flavonoids components. We believe that these components can be responsible to protect human erythrocytes exposed to high glucose concentrations against oxidative damage.

A versatile, stability-indicating and high-throughput ultra-fast liquid chromatography method for the determination of isoflavone aglycones in soybeans, topical formulations, and permeation assays

There is a growing interest in the pharmaceutical field concerning isoflavones topical delivery systems, especially with regard to their skin care properties and antiherpetic activity. In this context, the present work describes an ultra-fast liquid chromatography method (UFLC) for determining daidzein, glycitein, and genistein in different matrices during the development of topical systems containing isoflavone aglycones (IA) obtained from soybeans. The method showed to be specific, precise, accurate, and linear (0.1 to 5 µg mL(-1)) for IA determination in soybean acid extract, IA-rich fraction obtained after the purification process, IA loaded-nanoemulsions, and topical hydrogel, as well as for permeation/retention assays in porcine skin and porcine esophageal mucosa. The matrix effect was determined for all complex matrices, demonstrating low effect during the analysis. The stability indicating UFLC method was verified by submitting IA to acidic, alkaline, oxidative, and thermal stress conditions, and no interference of degradation products was detected during analysis. Mass spectrometry was performed to show the main compounds produced after acid hydrolysis of soybeans, as well as suggest the main degradation products formed after stress conditions. Besides the IA, hydroxymethylfurfural and ethoxymethylfurfural were produced and identified after acid hydrolysis of the soybean extract and well separated by the UFLC method. The methods robustness was confirmed using the Plackett-Burman experimental design. Therefore, the new method affords fast IA analysis during routine processes, extract purification, products development, and bioanalytical assays.

Effects of Bauhinia forficata Tea on Oxidative Stress and Liver Damage in Diabetic Mice.

This study was designed to evaluate the effects of Bauhinia forficata Link subsp. pruinosa (BF) tea on oxidative stress and liver damage in streptozotocin (STZ)-induced diabetic mice. Diabetic male mice have remained 30 days without any treatment. BF treatment started on day 31 and continued for 21 days as a drinking-water substitute. We evaluated (1) BF chemical composition; (2) glucose levels; (3) liver/body weight ratio and liver transaminases; (4) reactive oxygen species (ROS), lipid peroxidation, and protein carbonylation in liver; (5) superoxide dismutase (SOD) and catalase (CAT) activities in liver; (6) δ-aminolevulinate dehydratase (δ-ALA-D) and nonprotein thiols (NPSH) in liver; (7) Nrf2, NQO-1, and HSP70 levels in liver and pancreas. Phytochemical analyses identified four phenols compounds. Diabetic mice present high levels of NQO-1 in pancreas, increased levels of ROS and lipid peroxidation in liver, and decrease in CAT activity. BF treatment normalized all these parameters. BF did not normalize hyperglycemia, liver/body weight ratio, aspartate aminotransferase, protein carbonyl, NPSH levels, and δ-ALA-D activity. The raised oxidative stress seems to be a potential mechanism involved in liver damage in hyperglycemic conditions. Our results indicated that BF protective effect could be attributed to its antioxidant capacity, more than a hypoglycemic potential.

Catechins are not major components responsible for the beneficial effect of Camellia sinensis on the ovarian δ-ALA-D activity inhibited by cadmium.

Cadmium has been associated with a wide spectrum of deleterious effects on the reproductive tissues, including ovary. This investigation evaluated the protective role of Camellia sinensis (green, white and red teas) in the cadmium-induced inhibition of ovarian δ-aminolevulinate dehydratase (δ-ALA-D) activity in vitro and ex vivo. This study demonstrated that green and white teas restored the cow ovary δ-ALA-D activity inhibited by cadmium whereas red tea had no effect in vitro. In addition, green tea was able to restore enzyme activity inhibited after acute cadmium exposure in mice ovary. Teas infusions composition was assessed by HPLC in a quantitative assay for catechins, purine alkaloids and gallic acid as well as total polyphenol content. The greatest effect of green tea observed in vitro as well as the protective role presented in the ex vivo study could be attributed to the major content of phenols, but not catechins. In fact, catechins were not able to restore enzyme activity inhibited by cadmium, demonstrating that these compounds are not major components responsible for the beneficial effect of green tea observed in this study. This study demonstrated the helpful effect of green tea infusion in ameliorating a marker protein of cadmium intoxication in ovarian tissue.

Stability-Indicating HPLC Method for Posaconazole Bulk Assay

A stability-indicating liquid chromatographic (LC) method was developed for the determination of posaconazole in bulk. Chromatographic separation was achieved using an isocratic elution in a reversed-phase system, with a mobile phase composed of methanol-water (75:25, v/v), at 1.0 mL min−1 flow. Samples were exposed to degradation under thermal, oxidative and acid/basic conditions, and no interference in the analysis was observed. System suitability was evaluated and results were satisfactory (N = 4,900.00 tailing factor 1.04; RSD between injections = 0.65). The retention time of posaconazole was about 8.5 min and the method was validated within the concentration range 5–60 μg mL−1 (r = 0.9996). Adequate results were obtained for repeatability (RSD % = 0.86–1.22), inter-day precision (RSD % = 1.21) and accuracy (98.13% mean recovery). Robustness was also determined to be satisfactory after evaluation. The proposed method was successfully applied to posaconazole bulk quantification, showing the method is useful for determination of the drug in routine analysis.

UV derivative spectrophotometric method for determination of estradiol valerate in tablets

A derivative UV spectrophotometric method for determination of estradiol valerate in tablets was validated. The parameters specificity, linearity, precision, accuracy, limit of detection and limit of quantitation were studied according to validation guidelines. The first-order derivative spectra were obtained at N = 5, Δλ = 4.0 nm, and determinations were made at 270 nm. The method showed specificity and linearity in the concentration range of 0.20 to 0.40 mg mL-1. The intra and interday precision data demonstrated the method has good reproducibility. Accuracy was also evaluated and results were satisfactory. The proposed method was successfully applied to a pharmaceutical formulation.

LC/ESI-MS method applied to characterization of flavonoids glycosides in B. forficata subsp. pruinosa

Bauhinia forficata is used in folk medicine for its hypoglycemiant effect. In the south of Brazil, the subspecies pruinosa is found in a region with the characteristic flora, pampa biome. This species has been consumed by the local population as a tea for diabetes treatment. We studied the chemical composition of hydroethanolic extracts using LC/ESI-MS. The leaf extracts were prepared by percolation with 50% (v/v) ethanol. The chromatographic analyses were performed using a reverse-phase system, gradient elution with acetonitrile:phosphoric acid 0.05%, and ESI-MS in the positive ion mode. The chemical profile of the flavonoids was suggested to involve four quercetin and kaempferol glycosides.

Characterization of the antibiotic doripenem using physicochemical methods: chromatography, spectrophotometry, spectroscopy and thermal analysis

Doripenem was characterized through physicochemical and spectroscopic techniques, as well as thermal analysis. TLC (Rf = 0.62) and HPLC (rt = 7.4 min) were found to be adequate to identify the drug. UV and infrared spectra showed similar profile between doripenem bulk and standard. The 1H and 13C NMR analysis revealed chemical shifts that allowed identifying the drug. Thermal analysis demonstrated three steps with mass loss, at 128, 178 and 276 oC. The work was successfully applied to qualitative analysis of doripenem, showing the reported methods can be used for physicochemical characterization of doripenem

Effects of red wine tannat on oxidative stress induced by glucose and fructose in erythrocytes in vitro

The literature indicates that red wine presents in its composition several substances that are beneficial to health. This study has investigated the antioxidant effects of Tannat red wine on oxidative stress induced by glucose and fructose in erythrocytes in vitro, with the purpose to determine some of its majoritarian phenolic compounds and its antioxidant capacity. Erythrocytes were incubated using different concentrations of glucose and fructose in the presence or absence of wine. From these erythrocytes were determined the production of thiobarbituric acid reactive species (TBARS), glucose consumption, and osmotic fragility. Moreover, quantification of total phenolic, gallic acid, caffeic acid, epicatechin, resveratrol, and DPPH scavenging activity in wine were also assessed. Red wine showed high levels of polyphenols analyzed, as well as high antioxidant potential. Erythrocytes incubated with glucose and fructose had an increase in lipid peroxidation and this was prevented by the addition of wine. The wine increased glucose uptake into erythrocytes and was able to decrease the osmotic fragility of erythrocytes incubated with fructose. Altogether, these results suggest that wine leads to a reduction of the oxidative stress induced by high concentrations of glucose and fructose.

Chemical composition and hypotensive effect of Campomanesia xanthocarpa

Campomanesia xanthocarpa is known in Brazil as Guabiroba and is popularly used for various diseases, such as inflammatory, renal, and digestive diseases and dyslipidemia. The aim of the study was to analyze the chemical composition and investigate the effects of aqueous extract of C. xanthocarpa on the blood pressure of normotensive rats, analyzing the possible action mechanism using experimental and in silico procedures. The extract was evaluated for total phenolic compounds and total flavonoid content. The chemical components were determined by HPLC analyses. Systolic and diastolic blood pressure and heart rate were measured with extract and drugs administration. The leaves of C. xanthocarpa presented the relevant content of phenolics and flavonoids, and we suggested the presence of chlorogenic acid, gallic acid, quercetin, and theobromine. The acute administration of aqueous extract of C. xanthocarpa has a dose-dependent hypotensive effect in normotensive rats, suggesting that the action mechanism may be mediated through the renin-angiotensin system by AT1 receptor blockade and sympathetic autonomic response. Docking studies showed models that indicated an interaction between chlorogenic acid and quercetin with the AT1 receptor (AT1R) active site. The findings of these docking studies suggest the potential of C. xanthocarpa constituents for use as preventive agents for blood pressure.