Andrzej L. Dawidowicz

The role of human lungs in the biotransformation of propofol.

BackgroundThe metabolism of propofol is very rapid, and its transformation takes place mainly in the liver. There are reports indicating extrahepatic metabolism of the drug, and the alimentary canal, kidneys, and lungs are mentioned as the most probable places where the process occurs. The aim of this study was to determine whether the human lungs really take part in the process of propofol biotransformation. MethodsBlood samples were taken from 55 patients of American Society of Anesthesiologists grade 1–3 scheduled for elective intracranial procedures (n = 47) or for pulmonectomy (n = 8). All patients were premedicated with diazepam (10 mg) administered orally 2 h before anesthesia. Propofol total intravenous anesthesia was performed at the following infusion rates: 12 mg · kg−1 · h−1, 9 mg · kg−1 · h−1, and 6 mg · kg−1 · h−1. Fentanyl and pancuronium bromide were also administered intermittently. After tracheal intubation, the lungs were ventilated to normocapnia with an oxygen–air mixture (fraction of inspired oxygen = 0.33). Blood samples for propofol and 2,6-diisopropyl-1,4-quinol analysis were taken simultaneously from the right atrium and the radial artery, or the pulmonary artery and the radial artery. The concentration of both substances were measured with high-performance liquid chromatography and gas chromatography–mass spectroscopy. ResultsThe concentration of propofol in the central venous system (right atrium or pulmonary artery) is greater than in the radial artery, whereas the opposite is observed for propofol’s metabolite, 2,6-diisopropyl-1,4-quinol. Higher propofol concentrations are found in blood taken from the pulmonary artery than in the blood collected from the radial artery. ConclusionsHuman lungs take part in the elimination of propofol by transforming the drug into 2,6-diisopropyl-1,4-quinol.

Application of PLE for the determination of essential oil components from Thymus vulgaris L.

Essential plants, due to their long presence in human history, their status in culinary arts, their use in medicine and perfume manufacture, belong to frequently examined stock materials in scientific and industrial laboratories. Because of a large number of freshly cut, dried or frozen plant samples requiring the determination of essential oil amount and composition, a fast, safe, simple, efficient and highly automatic sample preparation method is needed. Five sample preparation methods (steam distillation, extraction in the Soxhlet apparatus, supercritical fluid extraction, solid phase microextraction and pressurized liquid extraction) used for the isolation of aroma-active components from Thymus vulgaris L. are compared in the paper. The methods are mainly discussed with regard to the recovery of components which typically exist in essential oil isolated by steam distillation. According to the obtained data, PLE is the most efficient sample preparation method in determining the essential oil from the thyme herb. Although co-extraction of non-volatile ingredients is the main drawback of this method, it is characterized by the highest yield of essential oil components and the shortest extraction time required. Moreover, the relative peak amounts of essential components revealed by PLE are comparable with those obtained by steam distillation, which is recognized as standard sample preparation method for the analysis of essential oils in aromatic plants.

Matrix solid-phase dispersion (MSPD) in chromatographic analysis of essential oils in herbs.

Matrix solid-phase dispersion (MSPD) is a simple and cheap sample preparation procedure allowing for the reduction of organic solvent consumption, exclusion of sample component degradation, improvement of extraction efficiency and selectivity, elimination of additional sample clean-up and pre-concentration step before chromatographic analysis. The paper shows the possibility of MSPD application for qualitative and quantitative analysis of essential oil components in the following herbs: thyme (Thymus vulgaris L.), mint (Mentha piperita), sage (Salvia officinalis L.), chamomile (Chamomilla recutita L.), marjoram (Origanum majorana L.), savory (Satureja hortensis L.), and oregano (Origanum vulgare). The results obtained using MSPD are compared to two other sample preparation methods: steam distillation (SD) and pressurized liquid extraction (PLE). The results presented in the paper prove that the total amount and the composition of the essential oil component obtained by MSPD are equivalent to those gained by one of the most effective extraction technique, PLE.

Thermal stability of 5-o-caffeoylquinic acid in aqueous solutions at different heating conditions.

Chlorogenic acid is a naturally occurring phenolic compound found in all higher plants. This component, being the ester of caffeic acid with quinic acid, is an important biosynthetic intermediate and plays an important role in the plants response to stress. Potential uses of chlorogenic acid are suggested in pharmaceuticals, foodstuffs, feed additives, and cosmetics due to its recently discovered biomedical activity. This finding caused new interest in chlorogenic acid properties, its isomers, and its natural occurrence. It has been found that as many as nine compounds (chlorogenic acid derivatives and its reaction product with water) can be formed from 5-o-caffeoylquinic acid during the heating of its water solution. Three of them, two hydroxylated 5-o-caffeoylquinic acid derivatives and 4,5-dicaffeoylquinic acid, have been not reported, yet. The amount of each formed component depends on the heating time and temperature. The presented results are important for researchers investigating plant metabolism and looking for new plant components. The transformation product can be mistakenly treated as a new component, not found before in the examined plant, or can be a cause of erroneous quantitative estimations of plant composition.

Optimization of ASE Conditions for the HPLC Determination of Rutin and Isoquercitrin in Sambucus nigra L

Abstract The accelerated solvent extraction (ASE) procedure has been examined as a sample preparation method for the HPLC analysis of rutin and isoquercitrin in Sambucus nigra L. The experimental extraction parameters (solvent composition, temperature, operation pressure, and static extraction time) have been optimized in order to receive the best recovery of both analytes from the flowers, leaves, and berries of black elder. The ASE recoveries obtained under the optimal extraction conditions were compared with analogous ones obtained by means of the maceration technique.

Does antioxidant properties of the main component of essential oil reflect its antioxidant properties? The comparison of antioxidant properties of essential oils and their main components

This study discusses the similarities and differences between the antioxidant activities of some essential oils: thyme (Thymus vulgaris), basil (Ocimum basilicum), peppermint (Mentha piperita), clove (Caryophyllus aromaticus), summer savory (Satureja hortensis), sage (Salvia hispanica) and lemon (Citrus limon (L.) Burm.) and of their main components (thymol or estragole or menthol or eugenol or carvacrol or camphor or limonene) estimated by using 2,2′-Diphenyl-1-picrylhydrazyl, 2,2′-azinobis(3-ethylbenzothiazoline-6-sulfonic acid) diammonium salt and β-carotene bleaching assays. The obtained data show that the antioxidant properties of essential oil do not always depend on the antioxidant activity of its main component, and that they can be modulated by their other components. The conclusions concerning the interaction of essential oil components depend on the type of method applied for assessing the antioxidant activity. When comparing the antioxidant properties of essential oils and their main components, the concepts of synergism, antagonism and additivity are very relevant.

Matrix solid-phase dispersion with sand in chromatographic analysis of essential oils in herbs.

INTRODUCTION Matrix solid-phase dispersion (MSPD) is a very simple, cheap and relatively quick sample preparation procedure which involves simultaneous disruption and extraction of various solid and semi-solid samples due to the direct mechanical blending of the sample with a SPE sorbent, mainly C(18). Little is known about MSPD application as a sample preparation method for the analysis of essential oil components in herbs. OBJECTIVE To evaluate if C(18) sorbent, commonly used in MSPD process, can be substituted with sand in the procedure of essential oil analysis. METHODOLOGY Essential oil extracts were obtained from mint, sage, chamomile, marjoram, savory and oregano using MSPD with C(18) sorbent or sand, pressurised liquid extraction and steam distillation. Their qualitative and quantitative compositions ware established by GC-MS and GC-FID. RESULTS The results prove that C(18) sorbent can be substituted with sand in the procedure of essential oil analysis in herbs. The recoveries of essential oil components estimated using MSPD/sand are almost equal to those using pressurised liquid extraction. CONCLUSION The results presented in the paper reveal that MSPD with sand is suitable for the isolation of essential oil components from herbs. Its extraction efficiency is equivalent to pressurised liquid extraction, recognised as one of the most efficient extraction methods. The cost of MSPD procedure for essential oil analysis can be significantly diminished by substituting C(18) with sand.

Static and dynamic superheated water extraction of essential oil components from Thymus vulgaris L.

Superheated water extraction (SWE) performed in both static and dynamic condition (S-SWE and D-SWE, respectively) was applied for the extraction of essential oil from Thymus vulgaris L. The influence of extraction pressure, temperature, time, and flow rate on the total yield of essential oil and the influence of extraction temperature on the extraction of some chosen components are discussed in the paper. The SWE extracts are related to PLE extracts with n-hexane and essential oil obtained by steam distillation. The superheated water extraction in dynamic condition seems to be a feasible option for the extraction of essential oil components from T. vulgaris L.

A study of the properties of octadecyl phases bonded to controlled-porosity glasses. II: Application in liquid chromatography

SummaryLiquid chromatography measurements have shown that the properties of C18 films bonded to the surface of controlled-porosity glass particles are different than those bonded on silica gel. The same conditions of the preparation procedure lead to much higher coverage density of the ODS chains on the boron-enriched surface as compared to silica gel. The results show the very high hydrophobicity of the obtained materials.

The influence of heavy metal stress on the level of some flavonols in the primary leaves of Phaseolus coccineus

Qualitative and quantitative analysis of flavonols was carried out in young and older primary leaves of runner bean plants (Phaseolus coccineus L.) treated with Cd2+ (25 µM) and Cu2+ excess (25 and 300 µM) for 12 days. The presence of quercetin-3-O-D-rhamnoside, kaempferol-3-O-D-rhamnoside, quercetin-3-O-D-glucuronide and kaempferol-3-O-D-glucuronide was found in the plant. Quercetin-3-O-D-rhamnoside predominated in the control and heavy metal-stressed plants. The content of individual flavonols increased under heavy metal treatment, particularly in young plants. The flavonol level depended on the metal and its concentration. A protective role of flavonols in plants under heavy metal stress is discussed.