Optimization of carvacrol,rosmarinic, oleanolic and ursolic acid extraction from oregano herbs (Origanum onites L., Origanum vulgare spp. hirtum and Origanum vulgare L.)

The aim of our study was to increase the extraction efficiency of carvacrol, rosmarinic, oleanolic and ursolic acid from the different species of oregano herbs (Origanum onites L., Origanum vulgare spp. hirtum and Origanum vulgare L.). Various extraction methods (ultrasound-assisted, heat-reflux, continuous stirring, maceration, percolation) and extraction conditions (different solvent, material:solvent ratio, extraction temperature, extraction time) were used, and the active substances were determined by HPLC. The lowest content of carvacrol, rosmarinic, oleanolic and ursolic acid was obtained by percolation. During heat-reflux extraction, the content of active substances depended on the solvent used: ethanol/non-aqueous solvent (glycerol or propylene glycol) mixture was more effective compared with ethanol alone. The results showed that for each species of oregano the most optimal extraction method should be selected to maximize the content of biologically active substances in the extracts.     

Screening of antioxidant activity and volatile compounds composition of Chamerion angustifolium (L.) Holub ecotypes grown in Lithuania

Since biological activity of medicinal plants is dependent on cultivation area, climatic conditions, developmental stage, genetic modifications and other factors, it is important to study flora present in different growing sites and geographical zones. This study was focused on screening of antioxidant activity of C. angustifolium harvested in six different locations in Lithuania. The total contents of phenolic compounds, flavonoids and 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging activity were evaluated by spectrophotometric methods. A correlation between radical scavenging activity and total phenolic compounds content was observed (correlation coefficient 0.98). HPLC with online post-column DPPH radical scavenging reaction detection was used for the separation of extracts. Oenothein B, rutin and one unidentified compound were predominant. Volatile compounds were analysed using solid-phase microextraction coupled with gas chromatography–mass spectrometry. Based on the analysis of volatiles, all samples were classified into two chemotypes: (I) with predominant α- and β-caryophyllenes and (II) with predominant anethole.     

Asymptotic Expansion for the Distribution Density Function of the Compound Poisson Process in Large Deviations

The paper is devoted to obtaining the asymptotic expansion and determination of the structure of the remainder term taking into consideration large deviations in the Cramér zone for the distribution density function of the standardized compound Poisson process. Following Deltuvien? and Saulis (Acta Appl Math 78:87–97, 2003. doi: 10.1023/A:1025783905023; Lith Math J 41:620–625, 2001) and Saulis and Statulevi?ius [Limit theorems for large deviations. Mathematics and its applications (Soviet Series), vol 73, pp 154–187, Kluwer, Dordrecht, 1991], the solution to the problem is achieved by first using a general lemma presented by Saulis (see Lemma 6.1 in Saulis and Statulevi?ius 1991, p. 154) on the asymptotic expansion for the density function of an arbitrary random variable with zero mean and unit variance and combining methods for cumulants and characteristic functions. By taking into consideration the large deviations in the Cramér zone for the density function of the standardized compound Poisson process, the result for the asymptotic expansion extends the asymptotic expansions for the density function of the sums of non-random number of summands (Deltuvien? and Saulis 2003, 2001).     

Distribution and chemical polymorphism of the essential oils of Achillea cartilaginea growing wild in Lithuania

The essential oils from 14 Achillea cartilaginea samples (leaves and flowers) collected from natural habitats in Lithuania were analysed by GC-MS. In total, 97 compounds were identified, 69 of which have not been reported previously in this species. In general, the essential oils of A. cartilaginea were rich in oxygenated monoterpenes. Remarkable chemical polymorphism was observed within the population of A. cartilaginea in Lithuania. It was observed that 1,8-cineole, camphor, cis-chrysanthenol, β-thujone, sabinol, chrysanthenone, terpinen-4-ol, bornyl acetate and β-sesquiphellandrene were the major constituents in the oils of the analysed plants. Hierarchical cluster analysis, which was based on the 19 major components exceeding 5% in the total oil, indicates the presence of several main chemical groups in the analysed plant populations.     

Stochastic Modelling of Temperature Variations with a View Towards Weather Derivatives

Daily average temperature variations are modelled with a mean‐reverting Ornstein–Uhlenbeck process driven by a generalized hyperbolic Lévy process and having seasonal mean and volatility. It is empirically demonstrated that the proposed dynamics fits Norwegian temperature data quite successfully, and in particular explains the seasonality, heavy tails and skewness observed in the data. The stability of mean‐reversion and the question of fractionality of the temperature data are discussed. The model is applied to derive explicit prices for some standardized futures contracts based on temperature indices and options on these traded on the Chicago Mercantile Exchange (CME).     

Matrix Solid-Phase Dispersion Extraction and UPLC Determination of Sudan Dyes in Chili Powder

A new method involving matrix solid-phase dispersion (MSPD) extraction and UPLC in conjunction with photodiode array detection was developed for the rapid and simple determination of Sudan dyes in chili powder. Separation of Sudan I, Sudan II, Sudan III, and Sudan IV was achieved within 2 min on the 1.7 μm Acquity UPLC BEH C18 column by using gradient elution with a mobile phase consisting of acetonitrile–water at a flow rate of 0.5 mL min^?1. Optimization of MSPD extraction parameters, such as type of solid sorbent and elution solvent were carried out. Optimal conditions selected for MSPD extraction were 0.25 g of sample, 0.5 g of silica gel as solid sorbent, and 7 mL of acetonitrile–methanol (9:1, v/v) as eluting solvent. Limits of detection ranged between 0.25 and 0.30 mg kg^?1 depending on the dye involved. All analytes provided average recoveries from spiked (at 1, 1.5, and 2 mg kg^?1) chili powder samples ranging from 81 to 106%. The method was applied to the analysis of chili powder samples obtained from different countries.     

Stable isotope ratio method for the characterisation of the poultry house environment

Stable isotope analysis was applied to describe the poultry house environment. The poultry house indoor environment was selected for this study due to the relevant health problems in animals and their caretakers. Air quality parameters including temperature, relative humidity, airflow rate, NH₃, CO₂ and total suspended particles, as well as mean levels of total airborne bacteria and fungi count, were measured. Carbon isotope ratios (¹³C/¹²C) were obtained in size-segregated aerosol particles. The carbon (¹³C/¹²C) and nitrogen (¹⁵N/¹⁴N) isotope ratios were measured in feed, litter, scrapings from the ventilation system, feathers and eggs. Additionally, the distribution of δ¹³C and δ¹⁵N values in different tissues of the chicken was examined. The airborne bacteria and fungi extracted from the air filters collected from poultry farms were grown in the laboratory in media with known isotope values and measured for stable isotope ratios. Analysis of isotope fractionation between microorganisms and their media indicated the applicability of stable isotope analysis in bulk samples for the identification of source material. The analysed examples imply that stable isotope analysis can be used to examine the indoor environment along with its biology and ecology, and serve as an informative bioanalytical tool.     

Particle‐Stabilized Water Droplets that Sprout Millimeter‐Scale Tubes

Millimeter‐scale tubes are observed to sprout from water droplets injected into a bath of toluene containing ethanol and silica colloids. This phenomenon requires that first a membrane is formed by the colloids which self‐assemble at the droplet interface, and second, that the ethanol preferentially partitions into the aqueous phase leading to an internal over‐pressure. Tube growth, eruption, and shuffling droplets are subsequently observed, depending on the concentration of ethanol and colloids selected. This work opens many possibilities in the field of biomimetic droplets for fundamental studies of artificial growth at the microscale and for emulsion‐related applications.     

Large deviations forU-statistics

Institute of Mathematics and Informatics, Akademijos 4, 2600 Vilnius, Lithuania. Published in Lietuvos Matematikos Rinkinys, Vol.32, No. 1, pp. 7–19, January–March,1992.