M. Satta

In‐vitro antimicrobial activity and chemical composition of Sardinian Thymus essential oils

Essential oils and their components are becoming increasingly popular as naturally occurring antimicrobial agents. In this work the chemical composition and the antimicrobial properties of Thymus essential oils and of their main components were determined. Three essential oils obtained from different species of Thymus growing wild in Sardinia and a commercial sample of Thymus capitatus oil were analysed. The essential oil components were identified by GC/MS analysis. The antimicrobial activity of the oils and components was determined against a panel of standard reference strains and multiple strains of food‐derived spoilage and pathogenic bacteria, using a broth microdilution method. The GC/MS analysis showed that the major constituents of the oils were monoterpene hydrocarbons and phenolic monoterpenes, but the concentration of these compounds varied greatly among the oils examined. The results of the antimicrobial assay showed that essential oils extracted from Sardinian Thymus species have an antimicrobial activity comparable to the one observed in other thyme oils. It seems also confirmed that the antimicrobial properties of thyme essential oils are mainly related to their high phenolic content. Among the single compounds tested carvacrol and thymol turned out to be the most efficient against both reference strains and food‐derived bacteria. The results of this study confirmed the possibility of using thyme essential oils or some of their components in food systems to prevent the growth of foodborne bacteria and extend the shelf‐life of processed foods.

Analysis of the Essential Oil of Helichrysum italicum G.Don ssp. microphyllum (Willd) Nym.

Abstract The chemical composition of Sardinian dwarf curry plant (Helichrysum italicum G.Don ssp. microphyllum (Willd.) Nym.) essential oils was studied. Oil samples were isolated by water and steam distillation of flowering tops collected at different locations. The constituents of the oils were analyzed by GC/MS. Since both the chemical composition and physicochemical characteristics of the oils obtained during these trials were significantly different, they were divided into two groups. One oil was rich in nerol (10.7%), neryl acetate (28.9%), neryl propionate (11.4%) and γ-curcumene (11.4%), while the other was rich in linalool (14.9%) and γ-curcumene (18.2%).

Chemical Composition of Rosmarinus officinalis Oils of Sardinia

Abstract Quantitative data relating to 20 components identified in a wide sampling of Sardinian rosemary oils are reported. Eleven oil samples were isolated by water and steam distillation of fresh branches and leaves of rosemary (Rosmarinus officinalis L.) from different areas in Sardinia, analyzed by gas chromatography, and the volatile components identified with a mass selective detector. The chemical composition of the Sardinian samples is quite homogeneous and rather different from that of the oils produced in other parts of Italy and other Mediterranean countries.

Residues behavior of some fungicides applied on two greenhouse tomato varieties different in shape and weight

The degradation of 12 fungicides (azoxystrobin, cymoxanil, cyproconazole, cyprodinil, fenarimol, fludioxonil, iprovalicarb, mepanipyrim, penconazole, pyrimethanil, tolclofos-methyl, triadimenol), commonly used in pest management strategies on Sardinian greenhouse tomato crops was studied. A different residue behaviour was observed between the studied cultivar. On the smaller, a “cherry” type tomato, field data showed an initial residue mostly higher than the “beefsteak” tomato. In any case, except for penconazole, all pesticide residues were below their maximum residue levels (MRLs) reaching the pre-harvest interval (PHI). On both cultivar, triadimenol and cymoxanil residues completely disappeared reaching their PHI, while iprovalicarb, fenarimol, and fludioxonil disappeared in a time of 17 to 24 days. On the contrary, azoxystrobin, cyproconazole, cyprodinil, penconazole, tolclofos-methyl, mepanipyrim, and pyrimethanil showed a long persistence on both tested cultivar and may have residual problems due to an accumulation effect if repeated field treatments will be performed. The first group of molecules according to their rapid degradation could be used in low pesticide-input management in order to obtain tomatoes with low or no detectable residues.

Determination of 28 pesticides applied on two tomato cultivars with a different surface/weight ratio of the berries, using a multiresidue GC-MS/MS method

The behavior of 28 pesticides on two tomato cultivars with a different surface/weight (S/W) ratio of the berries (S/W, Birikino vs. Tombola) was studied, in order to provide appropriate indications about their persistence on crops reaching the pre-harvest interval (PHI). Quantitative analysis was performed using a GC MS/MS method. Birikino cv. (BIR) was a “cherry type tomato” with a double S/W ratio compared with Tombola cv. (TOM). The results showed a different pesticide behavior. Azoxystrobin, Boscalid, Bupirimate, Difenoconazole, Etofenprox, Iprodione, Mepanipyrim, Myclobutanil, Tebuconazole, Zoxamide, Metalaxyl M, Pyrimethanil, Tetraconazole, Benalaxyl, Cyprodinil, Fenamidone, Famoxadone and Fludioxonil immediately after treatments showed residues on BIR higher than TOM, and this behavior is consistent with its greater exposed surface. BIR showed higher decay rates of these pesticides during the whole trial, nevertheless residue averages remained higher than TOM reaching the time of harvest. Residues at the PHI were all below their Maximum Residue Levels (MRLs), but data indicated that they could exceed their legal limits especially if the above-mentioned active ingredients were employed more than once per crop cycle on cherry type tomatoes. As regards to Chlorpyrifos, Chlorpyrifos methyl, Triadimenol, Pyridaben and Tebufenpyrad, no different residual behavior related to S/W ratio of the cultivars was observed. Even in this case, residues at the PHI were all below MRLs. As for Cyfluthrin, Deltamethrin, Lambda cyhalothrin, Etoxazole and Cyproconazole, residues were lower than the limit of quantitation (LOQ) of the analytical method just after the treatment, according to their low doses of employment.

Isolation of a Volatile Concentrate of Caraway Seed

Abstract A volatile concentrate of caraway seeds was isolated by supercritical C02 extraction coupled to a fractional separation technique. GC/MS analysis of the various fractions obtained at different extraction and fractionation conditions allowed the identification of the operating conditions to isolate the volatile concentrate. A good extraction performance was obtained operating at 90 bar and 50°C. The optimum fractionation was achieved by operating at 90 bar and -12°C in the first separator and at 10 bar and 17°C in the second. The influence of the extraction time on the composition was evaluated. A comparison with the hydrodistilled oil was also proposed.

Degradation of cyprodinil, fludioxonil, cyfluthrin and pymetrozine on lettuce after different application methods

Degradation of two fungicides (cyprodinil and fludioxonil) and two insecticides (cyfluthrin and pymetrozine) applied on iceberg and romaine lettuce under field conditions with different methods (portable mistblower and chemigation) was studied field data showed that both distribution methods and lettuce cultivar affect the degradation trends of examined pesticides. In these trials the residues of all active ingredients after pre-harvest time were less than fiftys maximum residue levels; the values in the romaine cultivar were generally higher than those in iceberg lettuce. After pre-harvest time residues of pesticides applied on romaine lettuce by portable motor sprayer were always higher than those obtained by the chemigation system.

Synthesis and pharmacological activity of 4-carbamoyl-5-aryl-6-methyl-4,5-dihydropyridazin-3 (2H)-ones

A new series of 4-carbamoyl-5-aryl-6-methyl-4,5-dihydropyridazin-3(2H)-ones have been synthesized and tested for their antiinflammatory and analgesic properties. Amongst the test compounds, only 31 showed antiinflammatory activity, though of shorter duration than that of indomethacin, taken as reference drug. On the contrary, many derivatives displayed relevant analgesic activity, 4--the only 4,5-dehydroderivative--being the most potent in the writhing test. In the hot plate test 3b, 3f and 3k were found to possess the most significant analgesic properties.

Influence of environmental conditions on the composition of Salvia desoleana Atzei & Picci oil

Abstract The effect of factors such as the parts of the plant utilized, the different types of soil and climatic conditions on the yield and composition of Salvia desoleana oil were investigated. The highest oil yields were obtained from the inflorescences harvested in June and July. The inflorescence oil was found to be rich in linalyl acetate (37.0%) and α-terpinyl acetate (20.3%), whereas the main component of the oil distilled from the biomass without inflorescences was α-terpineol (41.5-42.8%). The plants growing in calcareous soil produced an ester-rich oil while the alcohol component was higher in plants grown in chalk-free soil. The pH and the texture of the soils appeared to have little effect on the composition of the oil. S. desoleana showed itself able to adapt to different types of soil and climatic conditions and the phenology of the species is such that the flowers can be harvested twice a year.