Showing papers by "Snezana Agatonovic-Kustrin published in 2014"

Reversed Phase HPTLC-DPPH Free Radical Assay as a Screening Method for Antioxidant Activity in Marine Crude Extracts

Abstract: The large number of marine organisms present in the ocean, together with the diverse marine environments to which they have adapted, provides an enormous and mostly unexploited source of structurally novel and biologically active secondary metabolites . Some of these organisms have provided compounds that have served as important leads in the discovery of new drugs , as probes in molecular pharmacology , and use as pest control agents . In particular, they are a rich source of antioxidants but there has been limited work in screening organisms containing this rich source of structurally unique natural products for antioxidant activity. For instance, there are a large number of active components in macroalgae with antioxidant properties, including pigments such as polyphloroglucinols and fucoxanthin , bioactive carbohydrates such as fucoidan and laminarin, minerals, and UV absorbing mycosporine like amino acids . Glutathione, an important antioxidant in plants, animals, fungi and some bacteria, is found in all macroalgae with some species containing as much as 3082 mg/100 g

In silico modelling of pesticide aquatic toxicity.

Abstract: Human activities have introduced tens of thousands of chemicals into water systems around the world which has significantly impacted water quality and aquatic ecosystems. The aim of this study was to develop an in silico QSAR model, capable of predicting the aquatic toxicity of pesticides in terms of a lethal dose (LD50) for fish without requiring the use of in vivo testing. A large data set of 230 diverse pesticides, including fungicides, herbicides and insecticides, with experimentally measured LD50 values was used to develop a predictive QSAR model. Each pesticide molecule was described using 62 calculated molecular descriptors. These descriptors were then related to the LD50 values via an Artificial Neural Network. Sensitivity analysis was used to select descriptors that best describe the model. The developed model included 13 molecular descriptors related to lipophilicity, hydrogen binding and polarity. Note the value of the predictive squared correlation coefficient (q(2)) for the final model was 0.748, demonstrating the model's predictability. In the domain of QSAR studies, a q(2) value above 0.5 renders a model to be predictive. The model could therefore be used to accurately screen a wide range of compounds without the need for actual compound synthesis and to prioritize potentially toxic compounds for further testing.

For and against the use of methylated cyclodextrins in the development of midazolam solution for nasal application

Abstract: [Extract] Midazolam's imidazole ring helps provide stability in solution to hydrolytic degradation and fast metabolic inactivation. Because of its short half–life, myorelaxant, and amnesic properties, it is commonly used as a preoperative anesthetic agent, especially for the pediatric patients. A growing interest in alternative forms of drug administration has led to the development of nasal formulations.

Evaluation of high-performance thin-layer chromatography for the quantification of phenylpropanoids in commercial Echinacea products

Abstract: There is a large chemical variability between commercially available Echinacea for both research and consumption impacts on the quality and efficacy of these products. Globally, herbal industries are largely unregulated, leaving manufacturers responsible for quality control. Several recent efforts to improve regulation have created a need for rapid, accurate, and reliable assays suitable for a quality control setting. Thus, the aim of this study was to develop and validate a high-performance thin-layer chromatographic (HPTLC) method for the quantitative analysis of commercial Echinacea products. HPTLC and high-resolution plate imaging were used to separate and quantify the amounts of three phenylpropanoid compounds which were used then as markers in product quality assessment. The developed method was validated according to the current International Conference on Harmonization (ICH) guidelines in terms of accuracy, precision, linearity, specificity, limits of quantification and detection, and robustness a...