Ammodaucus Leucotrichus Cosson & Durieu fruits essential oil as corrosion inhibitor of tinplate in 0.5M oxalic acid medium and its thermodynamic properties

The anticorrosion proprieties of Ammodaucus leucotrichus Cosson & Durieu essential oil (ALEO) against the corrosion of tinplate in 0.5M oxalic acid medium was studied in the interest to improve the corrosion resistance of cans in interaction with food contains. For this, the gravimetric test, potentiodynamic polarization and electrochemical impedance spectroscopy (EIS) techniques were used. The different corrosion test used show that the ALEO has an anticorrosion effect with an inhibition efficiency of 83.83% at 4g.L-1, this can be pertained to the chemical composition of the studied essential oil. The essential oil behavior at rang temperature (303-373K) show that ALEO exhibits good inhibition even at moderate to high temperatures. The estimation of the corrosion activation parameters reveal that the essential oil shows good inhibitor characteristics with a physisorption mechanism. By using the scanning electron microscopy and energy dispersive X-rays (SEM-EDX), it is clear that the surface is remarkably improved in the presence of ALEO compared with that exposed to the acid medium without essential oil

Fractionation, dosage and rating of the antioxidant activity of the aqueous extract of Melissa Officinalis from northeastern Morocco

So far, many efforts have been made to discover phytochemical alternatives to chemically synthesized antioxidants. The candidate groups of natural molecules have appeared to be polyphenols and flavonoids. In this study, the amount of phenolic and flavonoid compounds in aqueous extracts of Melissa Officinalis, from North-East Morocco (TAZA), was explored by using two common approaches (Folin Ciocalteu and Aluminum Chloride). Their antioxidant capacity was assessed by DPPH free radical scavenging assay. The results obtained demonstrated that the two fraction of ethyl acetate and diethyl ether were rich in polyphenols (505 ± 26 and 378 ± 16 μg/mg respectively) and had moderate quantities of flavonoids (8 ± 0.1 and 10 ± 0.2 μg equivalent of routine per mg of extract). At 2 µg/ml the antioxidant activities of two fractions appeared to be a lower (70 and 71%) than that of ascorbic acid (83%)

Antifungal activity of Asteriscus graveolens (Forssk.) Less essential oil against Fusarium oxysporum f. sp. albedinis, the causal agent of “Bayoud” disease on date palm

Date palm (Phoenix dactylifera L.) is an important food source and commercial perennial crop in the Sahara and North Africa. “Bayoud”, a vascular wilt disease, incited by the soilborne fungal pathogen Fusarium oxysporum f. sp. albedinis (FOA), has become a serious threat to date production in date palm-growing regions in Morocco. Substantial body of research reported antifungal properties of a wide range of plant extracts. The present work aims to determine chemical composition and anti-FOA activity of Asteriscus graveolens (Forssk.) Less (AG) essential oil. GC/GC-MS analysis revealed the presence of forty-two distinct chemical components in the essential oil samples. The main compounds of the studied essential oils were 6-Oxocyclonerolidol (7.7–73.8%), cis-8-acetoxychrysanthenylacetate (0.6–50.1%) cis-chrysantenyl acetate (0.3–15.4%), 6-hydroxycyclonerolidol (2–13.3%), τ-cadinol (0.4–12.2%) and α-oxobisabolene (0.2–5.5%). Mycelial growth and spore germination of FOA were found to be strongly inhibited by the oil when tested using agar dilution assay. The lowest essential oil (EO) concentration that inhibits 100% of mycelial growth was 3500 ppm for leaves and 4000 ppm for aerial parts EO. These findings contribute significant insight into the potential of using plant extracts for controlling “Bayoud” disease

Antioxidant activity of phenols and flavonoids contents of aqueous extract of Salvia Officinalis origin in the North-East Morocco

Oxidative stress is responsible for several diseases. This phenomen has moved researchers into action in looking for new remedies «antioxidants». The aim of this work was to characterize the phenols and flavonoids compounds of extracts of Salvia Officinalis from  North-East Morocco (TAZA) in terms of antioxidant activity.  The antioxidant activityof this aromatic plant was determined according to the DPPH radical scavenging assay to suggest it as a new potential source of natural antioxidants. The quantification of phenolics and flavonoids compounds of solvent extracts (diethyl ether and ethyl acetate) were determined spectrometrically. Furthermore, The DPPH scavenging activity of extracts increased in the order diethyl ether extract < ethyl acetate extract < ascorbic acid. Finally, we suggest that the phenols and flavonoids compounds of Salvia Officinalis has significant potential as a natural antioxidant

Inhibitory effect of Acacia hamulosa methanolic extract on the corrosion of mild steel in 1 M hydrochloric acid

The flora of Saudi Arabia comprises about 18 species of Acacia species including Acacia hamulosa Benth. The methanolic extract of the flowering tops of A. hamulosa was tested for its radical scavenging activity toward 2,2-diphenyl-1-pricylhydrazyl (DPPH) radical and the activity was compared with L-ascorbic acid, quercetin and Trolox as standards. The total phenolic content was determined using Folin-Ciocalteu method. In addition the methanolic extract has been evaluated as a corrosion inhibitor for steel in 1 M HCl solution by means of weight loss measurements, potentiodynamic polarization, electrochemical impedance spectroscopy (EIS). Tafel polarization study revealed that extract of Acacia hamulosa acts as a cathodic type inhibitor. Inhibition was found to increase with increasing concentration of the extract of Acacia hamulosa. Values of inhibition efficiency calculated from weight loss, Tafel polarization curves, and EIS are in good agreement. The effect of temperature on the corrosion behaviour of mild steel in 1 M HCl with addition of extract was also studied and thermodynamic parameters were determined and discussed.               KEY WORDS: Acacia hamulosa, Extract, Polyphenols, Antioxidant corrosion, Electrochemical study Bull. Chem. Soc. Ethiop. 2018, 32(2), 323-335.DOI: https://dx.doi.org/10.4314/bcse.v32i2.1

Chemical composition of essential oil and antioxidant and anti-corrosion activity of extract and essential oil of Pennyroyal Mint (Mentha pulegium, MP)

View the growing success of natural products as an alternative to synthetic chemicals. The purpose of this study was to contribute to the valorization of leaves of Mentha pulegium by determining the chemical composition of its essential oil and evaluate in vitro the antioxidant and the anticorrosive activities of its aqueous extract and essential oil. The essential oil revealed 1,8-Cineole (31.9%) followed by piperitone (15.6%), Limonene (14.6%) and β-Pinene (4.8%) as the main constituents. The antioxidant activity of aqueous extract was evaluated by the method of DPPH radical scavenging. The extract and the essential oil of M. pulegium were tested as corrosion inhibitors of mild steel in 0.5 M H2SO4 using weight loss measurements and electrochemical methods. The aqueous extract exhibited a moderate antioxidant activity compared to acid ascorbic and the IC50 value was 36,62 µg/mL. The obtained  results  have showed that the inhibition efficiency increases with increasing  inhibitor  concentration  to  attain  90.3 % at  2 g/L of  MPE and 87.3 %  at 4g.L-1 of MPO at 303 K. Finally, extracts and essential oil of M. pulegium from Mediterranean origin have numerous potential as a substitute to chemical additives for the food industry

The Palm oil from seed of Phoenix dactylifera (Oil of both Deglet Nour and Kentichi) as a natural antioxidants and Environment-Friendly inhibitors on the Corrosion of mild Steel in HCl 1M

The flora of Republic of Algeria comprises a lot of Palm species, including Phoenix dactylifera. In this work, we used the Palm oil from seed of Phoenix dactylifera (Oil of both Deglet Nour and Kentichi). The objective of this study is divided into two parts. Firstly, determine the antioxidant activity of Palm oil from seed of Phoenix dactylifera (Oil of both Deglet Nour and Kentichi) according to the DPPH radical scavenging assay to suggest it as a new potential source of natural antioxidants, secondly, study the effect of inhibiting Palm oil from seed of Phoenix dactylifera (Oil of both Deglet Nour and Kentichi) on corrosion of mild steel in hydrochloric acid by electrochemical methods. Furthermore, The DPPH scavenging activity of Oil of both Deglet Nour and Kentichi increased in the order, Deglet Nour Oil < Kentichi Oil < ascorbic acid. The results of the polarization curves show that the corrosion current density decreases 577.9 μA/cm2 to 58μA/cm2 and to 59.3 μA/cm2 after addition of the inhibitor (oil of Deglet Nour and Kentichi respectively). The charge transfer resistance increases 21.69 ohm.cm2 to 186.5 ohm.cm2 and to 222.8 ohm.cm2 in the electrochemical impedance spectrum after addition of oil of Deglet Nour and Kentichi respectively. The inhibition of the compound effect is attributed to the formation of a film on the surface of the steel.

The inhibitive action of Pistacia lentiscus as a potential green corrosion inhibitor for mild steel in acidic medium

The aim of present work is to test the effect of the extract (PLE) and the essential oil (PLO) of Pistacia lentiscus as a potential green corrosion inhibitors for acidic media using weight loss measurements and electrochemical techniques (potentiodynamic polarization curves, and electrochemical impedance spectroscopy) in the presence of different concentrations of PLE & PLO ranging from 0.25 to 2 g/L. The inhibition efficiency was found to increase with increasing inhibitor concentration up to maximum 81.2 % and 92.1 % for PLO and PLE at 2g/L, respectively. Potentiodynamic polarization showed that PLE and PLO act as mixed type inhibitors. Nyquist plots show that the efficiency of inhibition increases with increasing concentration of PL and the increased charge transfer resistance. Adsorption of PLO and PLE on the steel surface followed a Langmuir’s isotherm and the thermodynamic parameters were determined and discussed.

Hydrogen effect modeling on Ziegler-Natta catalyst and final product properties in propylene polymerization

Hydrogen, as chain transfer agent, effects on kinetic of propylene polymerization; consequently variation of hydrogen concentration leads to change final product properties and also activates site of used catalyst. This phenomenon is one of the most important process variables is to adjust the final product properties and optimize the operating conditions. This work has attempted to present a mathematical model that cable to calculate the most important indices of end used product, such as melt flow index, number and weight average molecular weight and poly dispersity index. The model can predict profile polymerization rates determining important kinetic parameters such as the activation energy, lumped deactivation reaction initial reaction rate and deactivation constant. The mathematical model was implemented in Matlab/Simulink environment for slurry polymerization in laboratory scale. The modeling approach is based on polymer moment balance method in the slurry semi-batch reactor. In addition, in this work have provided a model that calculating fraction activated sites catalyst via hydrogen concentration. The model was validated by experimental data from lab scale, reactor. The experimental and model outputs were compared; consequently, the errors were within acceptable range.               KEY WORDS: Mathematical modeling, Propylene polymerization, Kinetics study, Hydrogen response, population balance Bull. Chem. Soc. Ethiop. 2018, 32(2), 371-386.DOI: https://dx.doi.org/10.4314/bcse.v32i2.1

Artemisia absinthium L. Aqueous and Ethyl Acetate Extracts: Antioxidant Effect and Potential Activity In Vitro and In Vivo against Pancreatic α-Amylase and Intestinal α-Glucosidase

Artemisia absinthium L. is one of the plants which has been used in folk medicine for many diseases over many centuries. This study aims to analyze the chemical composition of the Artemisia absinthium ethyl acetate and its aqueous extracts and to evaluate their effect on the pancreatic α-amylase enzyme and the intestinal α-glucosidase enzyme. In this study, the total contents of phenolic compounds, flavonoids, and condensed tannins in ethyl acetate and the aqueous extracts of Artemisia absinthium leaves were determined by using spectrophotometric techniques, then the antioxidant capacity of these extracts was examined using three methods, namely, the DPPH (2, 2-diphenyl-1picrylhydrazyl) free radical scavenging method, the iron reduction method FRAP, and the β-carotene bleaching method. The determination of the chemical composition of the extracts was carried out using high-performance liquid chromatography—the photodiode array detector (HPLC-DAD). These extracts were also evaluated for their ability to inhibit the activity of the pancreatic α-amylase enzyme, as well as the intestinal α-glucosidase enzyme, in vitro and in vivo, thus causing the reduction of blood glucose. The results of this study showed that high polyphenol and flavonoid contents were obtained in ethyl acetate extract with values of 60.34 ± 0.43 mg GAE/g and 25.842 ± 0.241 mg QE/g, respectively, compared to the aqueous extract. The results indicated that the aqueous extract had a higher condensed tannin content (3.070 ± 0.022 mg EC/g) than the ethyl acetate extract (0.987 ± 0.078 mg EC/g). Ethyl acetate extract showed good DPPH radical scavenging and iron reduction FRAP activity, with an IC50 of 0.167 ± 0.004 mg/mL and 0.923 ± 0.0283 mg/mL, respectively. The β-carotene test indicated that the aqueous and ethyl acetate extracts were able to delay the decoloration of β-carotene with an inhibition of 48.7% and 48.3%, respectively, which may mean that the extracts have antioxidant activity. HPLC analysis revealed the presence of naringenin and caffeic acid as major products in AQE and EAE, respectively. Indeed, this study showed that the aqueous and ethyl acetate extracts significantly inhibited the pancreatic α-amylase and intestinal α-glucosidase, in vitro. To confirm this result, the inhibitory effect of these plant extracts on the enzymes has been evaluated in vivo. Oral intake of the aqueous extract significantly attenuated starch- and sucrose-induced hyperglycemia in normal rats, and evidently, in STZ-diabetic rats as well. The ethyl acetate extract had no inhibitory activity against the intestinal α-glucosidase enzyme in vivo. The antioxidant and the enzyme inhibitory effects may be related to the presence of naringenin and caffeic acid or their synergistic effect with the other compounds in the extracts