Elfrides Eva Scherman Schapoval

Antimicrobial activity of some Hypericum species

The crude methanolic extracts of six species of Hypericum [H. caprifoliatum Cham. & Schlecht., H. carinatum Griseb., H. connatum Lam., H. ternum A. St. Hil., H. myrianthum Cham. & Schlecht. and H. polyanthemum Klotzsch ex Reichardt] growing in southern Brazil were analyzed for antimicrobial activity against several microorganisms (bacteria and fungi). The most active plant was H. caprifoliatum, which showed activity against Staphylococcus aureus. Only H. polyanthemum and H. ternum extracts were active against Bacillus subtilis. None of the crude methanolic extracts showed activity against S. epidermidis, Escherichia coli or Saccharomyces cerevisiae. Extracts from these species were evaluated chemically and tannin, flavonoid and phenolic acids were the prominent compounds. The plants contained quercitrin, hyperoside (except H. connatum) and, less frequently, isoquercitrin and chlorogenic acid. In contrast to H. perforatum, which has high concentrations of rutin, these species do not produce this flavonoid or it appears as traces. The tannin concentration varied between 5.1 and 16.7% in H. myrianthum and H. ternum, respectively.

Antifungal activity of the lemongrass oil and citral against Candida spp.

Superficial mycoses of the skin are among the most common dermatological infections, and causative organisms include dermatophytic, yeasts, and non-dermatophytic filamentous fungi. The treatment is limited, for many reasons, and new drugs are necessary. Numerous essential oils have been tested for both in vitro and in vivo antifungal activity and some pose much potential as antifungal agents. By using disk diffusion assay, we evaluated the antifungal activity of lemongrass oil and citral against yeasts of Candida species (Candida albicans, C. glabrata, C. krusei, C. parapsilosis and C. tropicalis). This study showed that lemongrass oil and citral have a potent in vitro activity against Candida spp.

Microbiological assay for azithromycin in pharmaceutical formulations.

The validation of a microbiological assay, applying the cylinder-plate method, for the determination of the antibiotic azithromycin is described. Using a strain of Micrococcus luteus ATCC 9341 as the test organism, azithromycin at concentrations ranging from 0.1 to 0.4 microgml(-1) could be measured in capsules and suspensions. A prospective validation of the method showed that it was linear (r=0.998), precise (RSD=1.40-capsules; RSD=1.19-powder for suspension and RSD=1.73-oral suspension) and accurate (it measured the added quantities). We conclude that the microbiological assay is satisfactory for quantitation of in vitro antibacterial activity of azithromycin.

Biological Activities and Essential Oil Composition of Leaves of Blepharocalyx salicifolius

Infusions obtained from dried and fresh leaves of Blepharocalyx salicifolius were assessed in antibacterial (with S. aureus and E. coli), antiinflammatory, antinociceptive, antispasmodic and intestinal transit models. All samples analyzed showed significant antibacterial activity against Gram-positive and Gram-negative bacteria. The highest activity was observed with the dried leaves against E. coli. An infusion from fresh leaves inhibited the stimulating action of acetylcholine on intestinal musculature (average inhibition 45%). Other biological assays gave no significant results with doses up to 300 and 600 mg/kg for dried and fresh material, respectively. The essential oil obtained from fresh leaves by hydrodistillation (0.9%) was analyzed by GC and GC/MS, where 42 components were identified. The main components were 1,8-cineole (25.2%), linalool (20.4%) and ß-caryophyllene (22.9%).

Chemical Constituents and Pharmacological Activities of Peschiera australis

AbstractSeven indole alkaloids (coronaridine, tabersonine, olivacine, coronaridine-hydroxyindolenine, catharinensine, decarbomethoxyvoacamine AND tabernamine) were isolated from Peschiera australis in Brazil. Four phenolic acids (vanillic acid, syringic acid, gentisic acid AND salicylic acid) were also found. Crude extracts of P. australis seeds AND leaves showed in vivo antineoplastic activity against two experimental tumor models: Ehrlichs carcinoma AND Sarcoma 180. Aqueous AND alcohol leaf extracts administered to rats 1 h before subplantar carrageenan injection had a significant dose-related anti-inflammatory effect. The same extracts also showed analgesic activity against acetic acid-induced abdominal writhing.

A simple, fast and cheap non-SPE screening method for antibacterial residue analysis in milk and liver using liquid chromatography-tandem mass spectrometry

In routine laboratory work, screening methods for multiclass analysis can process a large number of samples in a short time. The main challenge is to develop a methodology to detect as many different classes of residues as possible, combined with speed and low cost. An efficient technique for the analysis of multiclass antibacterial residues (fluoroquinolones, tetracyclines, sulfonamides and trimethoprim) was developed based on simple, environment-friendly extraction for bovine milk, cattle and poultry liver. Acidified ethanol was used as an extracting solvent for milk samples. Liver samples were treated using EDTA-washed sand for cell disruption, methanol:water and acidified acetonitrile as extracting solvent. A total of 24 antibacterial residues were detected and confirmed using liquid chromatography coupled to tandem mass spectrometry (LC-MS/MS), at levels between 10, 25 and 50% of the maximum residue limit (MRL). For liver samples a metabolite (sulfaquinoxaline-OH) was also monitored. A validation procedure was conducted for screening purposes in accordance with European Union requirements (2002/657/EC). The detection capability (CCβ) false compliant rate was less than 5% at the lowest level for each residue. Specificity and ruggedness were also discussed. Incurred and routine samples were analyzed and the method was successfully applied. The results proved that this method can be an important tool in routine analysis, since it is very fast and reliable.

Influence of penetration enhancers and molecular weight in antifungals permeation through bovine hoof membranes and prediction of efficacy in human nails.

This work aimed to evaluate the effect of different substances on the permeation of geraniol through bovine hoof membranes. Different penetration enhancers were able to increase the permeability up to 25 times compared to control. It was demonstrated that acetilcysteine in association with ascorbic acid increased the permeation, even in acid formulations. In addition, some antifungal drugs were incorporated into a gel formulation of HPMC containing acetylcysteine 5% and ascorbic acid 0.2% and then the permeation coefficient through bovine hoof membranes was evaluated. The relationship between permeability and molecular weight was established for fluconazole, miconazole, terbinafine, butenafine, geraniol and nerol. Geraniol and nerol, the antifungals with lower molecular weight, had the better permeability results. Permeability coefficients for nail plates were estimated and geraniol demonstrated similar or even better efficacy index values against T. rubrum, T. menthagrophytes and M. canis compared with terbinafine and miconazole.

Determination of quinolones and fluoroquinolones, tetracyclines and sulfonamides in bovine, swine and poultry liver using LC-MS/MS

Antibacterials are widely used in veterinary medicine. Residues of these drugs can remain in food of animal origin, including bovine liver. This paper describes a fast and simple analytical method for the determination of quinolones and fluoroquinolones, tetracyclines and sulfonamides in bovine liver samples. Deuterated enrofloxacin, sulfapyridine and demeclocycline were used as internal standards. The homogenised liver samples were extracted with acidified acetonitrile. Steps of non-solid-phase extraction (SPE) clean-up and concentration were used in the presented method. The final extracts were analysed by sensitive and selective detection of all components in a single run using LC-MS/MS. Acceptable recoveries between 66% and 110% were obtained. Good linearity (r2) above 0.96, considering three different days, for all drugs was achieved in concentrations ranging from 0.0 to 2.0 × the maximum residue limit (MRL). Intraday precision with coefficient of variation (CV%) (n = 6) lower than 14.7% and inter-day precision lower than 18.8% in agreement with European Commission Decision 2002/657/EC were obtained in concentrations ranging from 0.5 to 1.5 MRL. Accuracy was between 86% and 110%. Limits of detection and quantitation, as well as decision limit (CCα) and detection capability (CCβ), were also evaluated. Graphical Abstract

Identification, characterization and cytotoxicity in vitro assay of nitazoxanide major degradation product.

Stress studies of the broad-spectrum antiparasitic nitazoxanide were conducted in order to isolate and elucidate the major degradation product involved in thermal, acid, alkaline, oxidative and photolytic decomposition of the drug in solution and solid state. The major degradation product was identified and characterized using techniques namely LC-DAD, (1)H NMR, (13)C NMR, IR, and MS/MS. The stability of nitazoxanide raw material and nitazoxanide in tablets and in suspension powder was studied under different conditions and the results suggest the formation of the same deacetylated degradation product occur in all cases. This product was also studied in order to determine the preliminary cytotoxicity in vitro with mononuclear cells. Compared with nitazoxanide, the degradation product showed a higher cytotoxicity at a concentration of 40 μg mL(-1) after 48 h of incubation, under tested conditions. Therefore, stress studies showed that special care must be taken during the preparation, manufacture, and storage of this pharmaceutical drug.

Spectrophotometric Simultaneous Determination of Citral Isomers in Cyclodextrin Complexes with Partial Least Squares Supported Approach

This article describes the development and optimiza tion of a UV spectrophotometric method to evaluate the isomers of citral in cyclodextrins complexes by a p artial least squares (PLS) regression model. The ce ntral composite de- sign (CCD) associated with the response surface met hodology (RSM) was applied to select the wavelength range that provides the best prediction results. -cyclodextrin ( -CD) and hydroxypropyl- -cyclodextrin (HP- -CD) complexes with citral were prepared in ethanolic solution and spra y dried. These samples were analyzed by an optimize d PLS-UV model and the results compared with HPLC-UV determination s to evaluate the predictive power of the PLS-UV mo del. The re- sults from the PLS-UV model showed a relative stand ard deviation of prediction (RSEP) ranging from 0.8