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This study aims to evaluate the anticholinesterase activity of different extracts of Astragalus gombiformis Pomel, a wild desert species of Tunisia flora. The anticholinesterase activity of extracts was measured by the colorimetric method of Ellman et al. using human plasma as enzyme source. The effects of the incubation time and the temperature were also studied. Our finding showed that the anticholinesterase activity can be detected after a shorter incubation time than the time generally used for this assay. The temperature of 37°C seems to be more adequate for the evaluation of anticholinesterase activity. For an incubation time of 15 min, the extracts showed different activity levels. Among them, ethyl acetate aerial part extract was found the most active, with an IC50 of 110µg/ml. Considerable anticholinesterase activity of A. gombiformis extracts was shown and this finding suggests that this species can be a possible source of anticholinesterase natural products.

This study represents a contribution to the phytochemical investigation of Astragalus gombiformis Pomel, a wild desert species belong to family Fabaceae. It describes the phytochemical screening of wild and cultivated A. gombiformis parts and analyzes their volatile fractions by gas chromatography coupled with mass spectrometry. Many chemical groups such as alkaloids, tannins, coumarins, quinones, terpenoids and flavonoids were detected. Leaves were the richest part. Nevertheless, nitro compounds were not found in any part of this species. Twenty seven volatile compounds were detected by chromatographic analysis in differentparts, and fruits seem to be the richest part. Many active volatiles were identified, at relatively high amounts, such as (Z,Z,Z) 9,12,15-octadecatrienoic acid, (Z,Z) 9,12-octadecadienoic acid and butylated hydroxytoluene. The last compound, known by its antioxidant activity, was present in all parts. Further studies should be done to investigate the biological and toxicologic...

The aim of this study was to develop an analytical method for the determination of residues of organophosphorus and carbamate pesticides which are widely used in Tunisia. This method involves a liquid-liquid extraction procedure followed by liquid chromatography tandem mass spectrometry (LC/MS/MS) for the identification and quantification of compounds. Ionization of molecules was performed by the electrospray mode. Multiple reactions monitoring (MRM) was the acquisition mode used for the monitoring of two MS/MS transitions for each compound. The average recoveries obtained, at three different fortification levels, ranged between 65% and 106% for most of the pesticides studied, except for methamidophos (lower than 25%).The linearity of the method was in the range of 5 to 50 micro g/L with a correlation coefficient from 0.995 to 0.999, depending on the analyte. The estimated limit of detection and limit of quantification were 2 micro g/L and 5 micro g/L, respectively. The precision of the analytical procedure was satisfactory and the coefficients of variation, evaluated at three concentration levels were lower than 15% for most pesticides studied. The application of the method was investigated in a population of agricultural workers chronically exposed to various pesticides some of which, such as carbofuran, carbendazim, methomyl and pirimicarb, were detected in some serum samples.

A multiresidue method was assessed for the determination of several pesticides (organochlorine, organophosphorus, pyrethroids, triazole, amidine) using gas chromatography/mass spectrometry. The extraction of pesticides was carried out by liquid-liquid extraction (LLE) and solid-phase extraction (SPE) using two types of columns (CN and C18). The extracts were cleaned by the addition of florisil, the pesticides were separated by capillary column gas chromatography and detected by mass spectrometry in the electron impact mode. The extraction using C18 column provided the best results for most of the analyzed pesticides. The majority of pesticides recoveries from the four fruits and vegetables (apples, pears, tomatoes and pepper) were greater than 60%. Linearity and precision were satisfactory. The estimated limits of detection and limits of quantification ranged from 0.01 to 0.1 mg/kg and from 0.02 to 0.3 mg/kg, respectively. The proposed procedure was found to be useful for the multiresidue analyses of pesticides in agricultural products for routine monitoring programs.