Boubekeur Nadjemi

Phenolic extracts from various Algerian plants as strong inhibitors of porcine liver carboxylesterase

Carboxylesterases (CE), expressed at high levels in human liver and intestine, are thought to detoxify xenobiotics. The goal of this study was to study the effect of phenolic compounds from several plants from the Algerian Atlas used traditionally in Arab folk medicine on the enzymatic activity of porcine liver carboxylesterase. The plants have shown a potent inhibition of carboxylesterase (CE) enzymatic activity in a concentration-dependent manner. Results indicate that the Phenolic extracts from these plants lead to the inactivation of the CE pI = 5.1 with Ki values in micromolar range (1.4–38 μM). These results encourage further biological investigation and identification the inhibitors responsible for this activity.

In vitro starch digestion in sorghum flour from Algerian cultivars.

This work aims to evaluate starch digestion in whole sorghum grains. Nine sorghum cultivars were sampled from the Sahara of Algeria. The structural characteristics of sorghum grains were measured. Total starch (TS) varied between 67.67% and 74.82%, digestible starch (DS) between 64.34% and 69.70%, and resistant starch (RS) ranged from 2.55% to 7.98%. The kinetic of starch digestion displayed first-order model. For all sorghum cultivars, starch were digested with different extents, DS at infinite time (D∞) ranged from 52.58 to 102.13 g/100 g dry starch, while the hydrolysis index (HI) ranged from 41.55% to 76.93% and high average glycemic index (GIavg) ranged from 65.97 to 94.14. The results showed that there are differences in grain quality of Algerian sorghum cultivars. The starch fractions have acceptable nutritional value with good in vitro digestibility characteristics suitable for human health and nutrition.

Removal of Cyanide from Aqueous Solutions by Adsorption on Activated Carbon Prepared from Lignocellulosic By-products

Cyanide is considered one of the most dangerous compounds for the environment. They are discharged by various industries: chemical and metallurgical processes (extraction of gold and silver) and food industries. Adsorption is among the most used processes for elimination of cyanides particularly for the low concentrations. In this work, the cyanide removal is carried out by adsorption onto activated carbons prepared from olive stones and coffee ground. So we can promote this by-product as an inexpensive adsorbent. The prepared activated carbons are characterized by scanning electron micrograph and by determination of the physicochemical properties and specific surface area. All the adsorption experiments were performed in batch mode on synthetic water cyanide (KCN) at pH 10.8–11.0 to avoid volatilization of very toxic HCN. To describe the adsorption kinetics, the kinetic models of pseudo-first-order, pseudo-second-order, and intra-particle diffusion were applied. The experimental equilibrium data for adsorption of free cyanide were analyzed by the Langmuir, Freundlich, and Temkin isotherm models. GRAPHICAL ABSTRACT

Removal of cyanide in aqueous solution by oxidation with hydrogen peroxide in presence of activated alumina

This work is dedicated to the removal of free cyanide from aqueous solution by oxidation with hydrogen peroxide H2O2 catalyzed by neutral activated alumina. Effects of initial molar ratio [H2O2]0/[CN−]0, catalyst amount, pH, and temperature on cyanide removal have been examined. The presence of activated alumina has increased the reaction rate showing thus, a catalytic activity. The rate of removal of cyanides increases with rising initial molar ratio [H2O2]0/[CN−]0 but decreases at pH 10 to 12. Increasing the alumina amount from 1.0 to 30 g/L has a beneficial effect, and increasing the temperature from 20 °C to 35 °C improves cyanide removal. The kinetics of cyanide removal has been found to be of pseudo-first-order with respect to cyanide and the rate constants have been determined.

Algerian pearl millet ( Pennisetum glaucum L.) contains XIP but not TAXI and TLXI type xylanase inhibitors

An XIP (xylanase inhibiting protein) type xylanase inhibitor was purified from Algerian pearl millet ( Pennisetum glaucum L.) grains and characterized for the first time. Cation exchange and affinity chromatography with immobilized Trichoderma longibrachiatum glycoside hydrolase (GH) family 11 xylanase resulted in electrophoretically pure protein with a molecular mass of 27-29 kDa and a pI value of 6.7. The experimentally determined N-terminal amino acid sequence of the purified XIP protein is 87.5%, identical to that of sorghum ( Sorghum bicolor L.) XIP and 79.2% identical to that of wheat ( Triticum aestivum L.) XIP-I. The biochemical properties of pearl millet XIP are comparable to those described earlier for sorghum XIP, except for the higher specific activity toward a T. longibrachiatum GH family 11 xylanase. On the basis of immunoblot neither TAXI nor TLXI type xylanase inhibitors were detected in pearl millet grains.

Starch digestion in pearl millet ( Pennisetum glaucum (L.) R. Br.) flour from arid area of Algeria

To assess the nutritive value of minor cereals cultivated in arid areas of Algeria, nine pearl millet landraces were sampled from two regions: Tidikelt and Hoggar. Some qualitative and quantitative characters of the panicle and grain were measured, as well as in vitro starch digestion of the grain flour. Considerable variation was recorded in seed color, endosperm texture and nutritional value of starch and protein content. In vitro starch digestion displayed a first-order kinetic model. For all pearl millet landraces, starch was digested to a different extent; the hydrolysis index (HI) ranged from 22.29% to 35.52% and the expected glycemic index (eGI) ranged from 27.41 to 38.82. The results show that there is diversity in the physical and chemical properties of pearl millet accessions from the arid areas of Algeria: Tidikelt and Hoggar. This study confirms that pearl millet has an acceptable nutritional value with a low glycemic index suitable for human health and nutrition.

Removal of Pb(II) ions from aqueous solutions by raw and alkali-treated Degla Beida stone

AbstractThe purpose of this work was to study the feasibility of removing Pb(II) ions from aqueous solutions using specific type of date stones, Degla Beida (DB), using batch adsorption technique. The characterization by FT-IR analysis before and after the treatment process, during this study, has shown the presence of different functional groups. scanning electron microscope was used to analyze the surface change of the DB stone before and after alkali treatment. Batch experiments were conducted in order to measure the effects of different parameters on adsorption of Pb(II) ions, such as pH, contact time, amount of adsorbent, and ionic strength (CaCl2). The equilibrium adsorption data were interpreted using the Langmuir and Freundlich models, which shown that the Langmuir isotherm model fits the best with the highest determination coefficient R2 value. The kinetic studies shown that the adsorption of the Pb(II) ions onto raw and alkali-treated DB stones correspond to a pseudo-second-order kinetic model.