Quantitative determination of hydroxy pentacyclic triterpene acids in vegetable oils

A simple and precise analytical method for the determination of hydroxy pentacyclic triterpene acids (HPTAs) in vegetable oils was developed. The acidic fraction was isolated by solid-phase extraction using bonded aminopropyl cartridges, and the extract was silylated and analyzed by gas chromatography. Repeatability and recovery of the method were determined. In virgin olive oils, similar amounts of oleanolic (3beta-hydroxyolean-12-en-28-oic) and maslinic (2alpha,3beta-dihydroxyolean-12-ene-28oic) acids and traces of ursolic (3beta-hydroxyurs-12-en-28-oic) acid were found. The main factor affecting HPTA concentration was the oil quality since that increases as the quality decreases, while olive variety, olive ripeness, and oil extraction system had less influence. In crude olive pomace oils, the concentrations were very much higher than in virgin olive oils. During refining processes, total or significant losses of HPTAs were observed. Esterified derivatives of HPTAs were not found.     

Determination of phenols, flavones, and lignans in virgin olive oils by solid-phase extraction and high-performance liquid chromatography with diode array ultraviolet detection

A simple analytical method for the quantitative determination of phenols, flavones, and lignans in virgin olive oils was developed. The polar fraction was isolated from small amounts of oil sample (2.5 g) by solid-phase extraction (SPE) using diol-phase cartridges, and the extract was analyzed by reversed-phase HPLC coupled with diode array UV detection. Chromatographic separation of pinoresinol, cinnamic acid, and 1-acetoxypinoresinol was achieved. Repeatability (RSD < 6.5%), recovery (> 90%), and response factors for each identified component were determined. SPE on amino-phase cartridges was used for isolating acidic phenols and as an aid for phenol identification. For the first time, 2-(4-hydroxyphenyl)ethyl acetate was detected in olive oils. The aldehydic structure of the ligstroside aglycon was confirmed by NMR spectroscopy. The colorimetric determination of total o-diphenolic compounds by reaction with molybdate was consistent with their HPLC determination. Differences between results obtained by liquid-liquid extraction and SPE were not statistically significant.     

Relationships between oxidative stability, triacylglycerol composition, and antioxidant content in olive oil matrices

In olive oils, relationships between oxidative stability, glyceridic composition, and antioxidant content were investigated. Lipid matrices, obtained by purification of olive and high-oleic sunflower oils, were spiked with hydroxytyrosol, alpha-tocopherol, and mixtures of them and then subjected to oxidation in a Rancimat apparatus at 100 degrees C. At the same concentration of antioxidants, induction time (IT) decreased as the unsaturation rate of the matrix increased, but only fair correlations were found with fatty acid composition. Oxidative susceptibility (OS(TAG)) was calculated as a function of the relative oxidation rate of the triacylglycerols, and a linear relationship-IT (h) = (a + b)OS(TAG)-between induction time and this parameter showed a good correlation coefficient (r > 0.990, p < 0.001). In the case of matrices with a single antioxidant, origin ordinate (a) and slope (b) can be calculated as a function of the antioxidant concentration. In matrices spiked with mixtures of hydroxytyrosol and alpha-tocopherol, a simple relationship between the coefficients a and b and the concentration of antioxidants cannot be established because additive and subtractive effects occur depending on the relative concentrations of both antioxidants. However, approximate values for these coefficients can be obtained, allowing the estimation of the oil stability. In various olive oils, an acceptable agreement was found between the IT experimentally determined and that calculated from the oil composition. These results confirmed that the Rancimat stability of olive oils mainly depends on triacylglycerol composition and concentrations of o-diphenols and alpha-tocopherol.     

Comparison of diazepam–ketamine and thiopentone for induction of anaesthesia in healthy dogs

Objective To compare the anaesthetic and cardiopulmonary effects of a diazepam–ketamine combination with thiopentone for induction of anaesthesia in dogs. Animal population Twenty healthy dogs of various breeds weighing between 3.8 and 42.6 kg undergoing major orthopaedic or soft tissue surgery. Materials and methods Pre‐anaesthetic medication in all cases was intramuscular acepromazine and methadone given 30 minutes before induction of anaesthesia. Each animal was then randomly assigned to receive either thiopentone or diazepam and ketamine. Quality of conditions for, and time to tracheal intubation were recorded. Anaesthesia was maintained with halothane in oxygen and nitrous oxide. Heart rate, respiratory rate, systolic blood pressure, end tidal carbon dioxide tensions and oxygen saturation were recorded at 10 minute intervals throughout surgery. The quality of recovery from anaesthesia was assessed. Results The quality of induction in both groups was satisfactory. The total mean time (± SD) to tracheal intubation (162 ± 84 seconds) was significantly longer in dogs receiving diazepam and ketamine compared to dogs receiving thiopentone (62 ± 28 seconds). Heart rate, systolic blood pressure and end tidal carbon dioxide concentration were not significantly different between groups. Respiratory rate was significantly higher in the diazepam–ketamine group between 0 and 30 minutes. The quality of recovery was similar in each group. Conclusions There appear to be fewer differences between the induction agents examined in this study than was previously believed. No pressor, or other cardiovascular stimulating effects were detected in the dogs that received diazepam and ketamine. Clinical relevance The absence of obvious differences between groups suggests that pre‐anaesthetic medication, inhaled anaesthetics and the physiological effects of surgery itself probably had a greater effect on the variables studied than the induction agent used. Further studies are required to determine whether diazepam and ketamine offers significant advantages over other induction agents in the unhealthy dog.     

The influence of abscisin II and gibberellic acid on the sprouting of excised potato buds

Summary It was shown that abscisin II at low concentration (0.5–10⁻⁵ M) has a significant growth inhibiting effect on the sprouting of excised potato buds. The growth accelerating effect of GA is partly suppressed by abscisin II. No effect could be observed on the length of the dormant period. GA seems to have a negative influence on the root formation. Combined treatment with GA and abscisin II nearly completely inhibited root formation.     

Dynamics of lead and cadmium in body of bees consuming food polluted by these elements

The dynamics of accumulation of lead and cadmium in different bee body sections and organs during consumption of carbohydrate food polluted by these elements are studied. The maximum biological absorption coefficients of these elements are noted in rectums. Therefore, it is recommended to use them for monitoring pollution of bee bodies and melliferous vegetation.     

Evaluation of the effect of long use of straw on restoration of organic matter in sod-podzolic soil

The paper shows results of the investigation of quantitative parameters of changes in common and readily decomposable organic matter in the sod-podzolic sandy loam soil under long-term use of straw of cereals and legumes as fertilizer for two 5-field grain-row crop rotations.     

Biomechanical Evaluation of Different Numbers, Sizes and Placement Configurations of Ligaclips Required to Secure Cellophane Bands

Objective— To determine the number, size, and configuration of ligaclips most resistant to tensile forces when applied to cellophane bands.
Study Design— In vitro mechanical evaluation.
Sample Population— Single-layer and triple-layer cellophane bands, 9.0 and 11.5 mm ligaclips.
Methods— Triple-layer bands were secured with a different number (2–5), size (9.0 or 11.5 mm) or configuration (linear or alternating placement) of ligaclips and mechanically tested. Force-deformation curves were generated and yield load in Newtons (N) was determined for each variable. A 3-way analysis of variance with post hoc Tukey's tests was used for statistical comparisons. Yield load for single-layer and triple-layer bands secured with 4 alternating 11.5 mm ligaclips was compared using a paired-sample (independent) t-test with P <.05 considered significant.
Results— Mean yield load increased as the number of ligaclips applied increased, but this effect began to plateau after application of the 4th clip. Mean yield load for 11.5 mm ligaclips was significantly higher than for 9.0 mm ligaclips ( P <.001) and for the alternating configuration compared with the linear configuration ( P <.001). Yield load for 4 alternating 11.5 mm ligaclips applied to triple-layer cellophane bands was significantly greater than the same configuration applied to single-layer cellophane bands ( P <.001).
Conclusion— 11.5 mm ligaclips applied in an alternating configuration and on triple-layer cellophane provided most resistance to tensile forces. The resistance to tensile forces increased significantly as the number of ligaclips applied increased from 1 to 4/band.
Clinical Relevance— Surgeons should be aware that the number, size, and configuration of ligaclips and cellophane thickness affect their resistance to tensile forces.     

New lipophilic tyrosyl esters. Comparative antioxidant evaluation with hydroxytyrosyl esters

New lipophilic esters of tyrosol, a naturally occurring phenol with interesting biological properties, have been synthesized in good yields by a chemoselective procedure, using lipase from Candida antarctica or p-toluenesulfonic acid as catalysts. Their antioxidant activities have been evaluated by the Rancimat test in lipophilic food matrices, as well as by FRAP and ABTS assays in methanolic solutions, and compared with those of previously synthesized hydroxytyrosyl esters. Free tyrosol, hydroxytyrosol, butylhydroxytoluene, and alpha-tocopherol were used as standards. All methods used for the antioxidant activity evaluation emphasized the high influence of the ortho-diphenolic structure on the antioxidant capacity, tyrosol and its derivatives being less active than hydroxytyrosol and its analogues and even less than BHT and alpha-tocopherol. In addition, the Rancimat test revealed a lower activity for ester derivatives than for their respective reference compounds (HTy or Ty), in agreement with the polar paradox. On the other hand, FRAP and ABTS methods reported an opposite behavior between the synthetic esters and their respective references. Thus, hydroxytyrosyl esters were more active than HTy, whereas tyrosyl esters were less active than Ty. The length and nature of the acyl side chain did not seem to play an important role in the antioxidant activity of either the hydroxytyrosyl or tyrosyl ester series, since no significant differences were observed among them.