Antimicrobial efficacy of the marjoram essential oil (MEO) on organic vegetables inoculated with 4 log/cfu Salmonella enterica serovar Schwarzengrund was evaluated. Previously inoculated samples of smooth lettuce (Lactuva sativa), kale (Brassica oleracea) and arugula (Eruca sativa) were immersed, separately, in three MEO solutions (0.1, 0.3 and 0.5%) for 1 and 2 min. Control groups with sterile phosphate-buffered saline and sodium hypochlorite (250 ppm) solution were also used. The enumeration of Salmonella was performed for 3 consecutive days, and the essential oil yielded an average reduction in microbial load, ranging from 2.12-3.31 log/cfu, in all samples, against 1.86-2.81 log/cfu obtained by the traditional disinfection method with hypochlorite solution. In lettuce samples, the 0.5% MEO concentration showed similar efficacy to the hypochlorite control. The same concentration of essential oil tested in kale and arugula showed significant antimicrobial activity when compared to the same control. Sensory and affective tests showed good acceptability of the MEO flavor on lettuce leaves. According to this experimental model, this oil has promising antimicrobial activity against Salmonella enterica serovar Schwarzengrund and may be used to reduce or replace sodium hypochlorite during the disinfection process of vegetables.Practical ApplicationsThe marjoram essential oil at 0.5% concentration showed potential application in the disinfection process of vegetables for human consumption. Its disinfection capacity against a high concentration of multidrug-resistant Salmonella enterica serovar Schwarzengrund was similar or even better than the sodium hypochlorite solution commonly used to remove or reduce the microbial load of fresh vegetables or similar foods.

Structure elucidation and conformation analysis of four proanthocyanidins isolated from the bark of Parapiptadenia rigida were performed by two-dimensional NMR spectroscopy, HRESIMS, CD, and molecular mechanics (MM+) force field calculations. The known prodelphinidin, epigallocatechin-(4β→8)-epigallocatechin-3-O-gallate (1) was accompanied by the new epigallocatechin-(4β→8)-4'-O-methylgallocatechin (2), epicatechin-(4β→8)-4'-O-methylgallocatechin (3), and (4α→8)-bis-4'-O-methylgallocatechin (4). Compound 4 was previously published but the earlier structure must presumably be revised to 4'-O-methylgallocatechin-(4α→8)-4'-O-methylepigallocatechin. Conformational studies showed the compact rotamer with B and E rings in quasi-equatorial orientations as the preferred conformation for compounds 1-3, whereas 4 consists of two stable rotamers, each with a quasi-equatorial orientation of ring B and E, respectively. The isolated compounds were studied for their wound-healing effects in a scratch assay and showed promising results.

Analysis of the ethanolic extract of the bark from Parapiptadenia rigida resulted in the isolation of the new catechin derivatives 4',3''-di-O-methylapocynin-D (10), 4',3''-di-O-methylapocynin-B (11), epigallocatechin-3-O-ferulate (8), and 4'-O-methylepigallocatechin-3-O-ferulate (9) and the catechins 4'-O-methylepigallocatechin-3-O-gallate (6) and 4'-O-methylepicatechin-3-O-gallate (7). These compounds, isolated for the first time from a natural source, are accompanied by the five known catechins 4'-O-methylgallocatechin (1), 4'-O-methylepigallocatechin (2), 3'-O-methylepicatechin (3), epigallocatechin-3-O-gallate (4), and epicatechin-3-O-gallate (5). Compounds 5 and 7 displayed promising wound-healing effects in a scratch assay. Some of the catechin derivatives showed inhibitory effects on NF-κB DNA binding and p38α MAPK activity.

Cefuroxime (CFU) is a semi-synthetic cephalosporin with a relatively broad-spectrum antimicrobial activity, and belongs to the second generation of cephalosporins. Regarding the quality control of medicines, a validated microbiological assay for determination of cefuroxime sodium in pharmaceutical formulations has not been reported yet With this purpose, this paper reports the development and validation of a simple, sensitive, accurate and reproducible agar diffusion method to quantify CFU sodium in injectable formulations. The assay is based on the inhibitory effect of CFU upon the strain of Staphylococcus aureus ATCC 6538P used as test microorganism. The results were treated statistically by analysis of variance and were found to be linear (r = 0.9998) in the selected range of 8.0-32.0 mu g/ml; precise [repeatability: relative standard deviation (RSD) = 1.56%; intermediate precision: between-day RSD = 1.27%; between analyst RSD = 1.13%] and accurate (101.58%). The bioassay specificity was studied by evaluation of degraded sample at 50 degrees C with analysis at 0, 24 and 48 h in parallel with the pharmacopeial liquid chromatography method for CFU. The results demonstrated the validity of the proposed bioassay, which allows reliable quantitation of CFU sodium in pharmaceutical samples and therefore can be used as a useful alternative methodology for the routine quality control of this medicine. (C) 2009 Elsevier B.V. All rights reserved.

Ceftazidime (CFZ) is a broad spectrum parenteral beta-lactam antibiotic of the cephalosporin family. This paper reports the development and validation of an agar diffusion microbiological assay using the cylinder-plate method for determination of CFZ in powder for injection. The validation carried out yielded good results in terms of linearity, precision, accuracy, selectivity, and robustness. The assay is based on the inhibitory effect of CFZ upon the strain of Pseudomonas aeruginosa ATCC 27853 used as the test microorganism. The results of the assays were treated statistically by analysis of variance and were found to be linear (correlation coefficient = 0.999998) in the selected range of 8.0-32.0 microg/mL; precise [repeatability: relative standard deviation (RSD) = 1.11%; intermediate precision: between-day RSD = 1.37% and between-analyst RSD = 1.41%]; and accurate. The selectivity of the bioassay was evaluated by analysis of degraded samples at 50 degrees C, and the results were compared with a pharmacopeial liquid chromatographic method at the time 0, 24, and 48 h. The results demonstrated the validity of the proposed bioassay, which allows reliable quantitation of CFZ in pharmaceutical samples and can be used as a useful alternative methodology for CFZ analysis in routine quality control.

Cefepime is a new parenteral cephalosporin that has been described as a fourth-generation, broad-spectrum antibiotic. This paper reports the development and in-house validation of an agar diffusion bioassay using a cylinder-plate method for the determination of cefepime in powder for injection. The validation performed yielded good results in terms of linearity, precision, accuracy, and robustness. The assay is based on the inhibitory effect of cefepime upon the strain of Micrococcus luteus ATCC 10240 used as the test microorganism. The results of assays were treated statistically by analysis of variance (ANOVA) and were found to be linear (r = 0.99993) in the selected range of 8.0-32.0 microg/mL; precise [repeatability: relative standard deviation (RSD) = 1.39%, intermediate precision: between-day RSD = 1.77%, and between-analyst RSD = 1.97%] and accurate. Comparison of bioassay and liquid chromatography by ANOVA showed no significant difference between methodologies. The results demonstrated the validity of the proposed bioassay, which is a simple and useful alternative methodology for cefepime determination in routine quality control.

An accurate, simple, reproducible, and sensitive liquid chromatographic method was developed and validated for the determination of omeprazole in powder for injection and in pellets. The analyses were performed at room temperature on a reversed-phase C18 column of 250 x 4.6 mm id, 5 microm particle size. The mobile phase, composed of methanol-water (90 + 10, v/v), was pumped at a constant flow rate of 1.5 mL/min. Detection was performed on a UV detector at 301 nm. The method was validated in terms of linearity, precision, accuracy, and ruggedness. The response was linear in the range 32-48 microg/mL (r2 = 0.9976). The relative standard deviation values for intra- and interday precision studies were 1.22 and 1.56% for injectable and 2.13 and 2.45% for pellets, respectively. Recoveries ranged between 95.81 and 100.48%.