Artemisia judaica (ArJ) is a Mediterranean aromatic plant used traditionally to treat gastrointes... more Artemisia judaica (ArJ) is a Mediterranean aromatic plant used traditionally to treat gastrointestinal ailments, skin diseases, atherosclerosis, and as an immuno-stimulant. This study describes ArJ essential oil constituents and investigates their wound healing activity. The in vitro antioxidant and antibiofilm activities of ArJ essential oil were investigated. The in vivo pro/anti-inflammatory and oxidative/antioxidant markers were compared with standard silver sulfadiazine (SS) in a second-degree skin burn experimental rat model. The gas chromatography-equipped flame ionization detector (GC-FID) analysis of ArJ essential oil revealed the major classes of compounds as oxygenated monoterpenes (>57%) and cinnamic acid derivatives (18.03%). The antimicrobial tests of ArJ essential oil revealed that Bacillus cereus, Candida albicans, and Aspergillus niger were the most susceptible test organisms. Two second-degree burns (each 1 inch square in diameter) were created on the dorsum of ...
Chitosan hydrogels were prepared by gamma radiation grafting of acrylamide (AAm) onto chitosan (C... more Chitosan hydrogels were prepared by gamma radiation grafting of acrylamide (AAm) onto chitosan (CS). The gelation (%) increased as the AAm content was raised up to the CS/AAm ratio of 1/10 wt%. The grafting yield and the grafting ratios of the Poly(CS/AAm) hydrogel were found to be directly proportional to the increase in AAm contents. The swelling behavior was more pronounced with higher AAm content up to 1/15 wt% in the Poly(CS/AAm), and then decreased with further rise of the AAm content to 1/20 wt%, because of the formation of a highly crosslinked hydrogel, with high hydrogen bonding. The prepared Poly(CS/AAm) hydrogels were characterized by using FTIR, TGA and SEM techniques. The analysis confirmed successful preparation of Poly(CS/AAm) with different compositions. The adsorption capacity of the Poly(CS/AAm) hydrogel with the composition of (1:10 wt%) towards Nigrosin acid dye was found to be higher than that of the other hydrogel formulations. This may be due to the fact that the selected Poly(CS/AAm) hydrogel possesses a highly pronounced swelling behavior and a highly crosslinked structure, compared to the other prepared hydrogels. It has been also noted that the adsorption capacity of the 1:10 wt% Poly(CS/AAm) hydrogel enhanced markedly at pH 2, but decreased at higher pH values, namely, from pH 5 to pH 7.4. This can be explained by the protonation of amide groups of acrylamide and amine groups of chitosan occurring at lower pH. The high adsorption properties of the selected Poly(CS/AAm) hydrogel recommend it as a necessary bioremediation solution to face the high level of acid dye pollutants, such as Nigrosin, in industrial effluents.
The blending of polyvinyl alcohol (PVA) with starch with different content of citric acid as cros... more The blending of polyvinyl alcohol (PVA) with starch with different content of citric acid as crosslinker and glycerol as plasticizer were performed by casting method. The hydroxyl groups of PVA and Starch react with the citric acid (1 %) and glycerol (10 vol %) to form crosslinked network. The FTIR spectral analyses show the successful preparation of the different composition of the prepared PVA/ Starch /Citric acid/Glycerol bioblend films. It is found that the prepared PVA/ Starch /Citric acid/Glycerol with composition (2:1:1/10 vol %) bioblend film characterized by higher water resistance, good mechanical and higher thermal stability than other prepared bioblend films. The using of gamma radiation improved and modified water resistance property were the water uptake at equilibrium reduced remarkably at dose of 10 kGy. Also the thermal stability increased as irradiation dose increased up to dose of 30 kGy The improved mechanical and thermal properties of the selected PVA/ Starch /C...
Four halophytic plants, Lycium shawii, Anabasis articulata, Rumex vesicarius, and Zilla spinosa, ... more Four halophytic plants, Lycium shawii, Anabasis articulata, Rumex vesicarius, and Zilla spinosa, growing in the central Qassim area, Saudi Arabia, were phytochemically and biologically investigated. Their hydroalcoholic extracts’ UPLC-ESIQ-TOF analyses demonstrated the presence of 44 compounds of phenolic acids, flavonoids, saponins, carbohydrates, and fatty acids chemical classes. Among all the plants’ extracts, L. shawii showed the highest quantities of total phenolics, and flavonoids contents (52.72 and 13.01 mg/gm of the gallic acid and quercetin equivalents, respectively), along with the antioxidant activity in the TAA (total antioxidant activity), FRAP (ferric reducing antioxidant power), and DPPH-SA (2,2-diphenyl-1-picryl-hydrazyl-scavenging activity) assays with 25.6, 56.68, and 19.76 mg/gm, respectively, as Trolox equivalents. The hydroalcoholic extract of the L. shawii also demonstrated the best chelating activity at 21.84 mg/gm EDTA equivalents. Among all the four halophy...
International Journal of Environmental Science and Technology, 2016
Two fungi were isolated and examined to decolorize crystal violet dye, frequently used as textile... more Two fungi were isolated and examined to decolorize crystal violet dye, frequently used as textile dye and in microorganism staining, using basal salt medium under static condition at 30 °C. The more effective fungus gave less dry weight and lower pH indicating that the process was directed toward the decolorization process giving acidic products rather than microbial growth. The effective fungus was identified as Aspergillus niger and was used in the rest of experiments. Increasing the incubation period more than 10 days did not improve the decolorization process, while the best pH was 5.5. The decolorization process was effective (up to 84.6 %) with the examined range of dye concentrations (10–40 ppm). Sucrose content, as a carbon source, more than 1 % did not improve the decolorization process (80.9 %). Using ammonium sulfate as a nitrogen source, instead of sodium nitrate in the original basal medium, lowered the decolorization process, while using corn steep liquor enhanced the biodegradation up to 96.1 %. Although the dye violet color vanishes in acid medium because of decreasing the possibility of extending the benzene chromophore as a result of binding the nitrogen lone pair in the ammonium ion, the UV–Vis spectra and LC–MS–ESI analysis of the bioassay products proved that the decolorization is due to the biodegradation of the dye rather than the resonance factor in acidic medium or biosorption by fungus mycelia.
International Journal of Biological Macromolecules, 2016
The copolymerization of starch with acrylic acid AAc using direct gamma radiation technique was p... more The copolymerization of starch with acrylic acid AAc using direct gamma radiation technique was performed. The effect of AAc concentrations on the gel (%) and swelling behavior were investigated. It is found that as AAc concentrations increase both gel(%) and swelling behavior increase. The Poly(starch/acrylic acid) (1:10wt%) hydrogel were selected due to its high swelling properties. From the in-vitro release study of the rutin-loaded hydrogel it is observed that it is strong pH-dependent release behavior, thus offering a maximum release as pH increased. The dextran sulphate sodium (DSS)-induced rat colitis model was treated with rutin-loaded Poly(starch/acrylic acid) (1:10wt%) hydrogel and free rutin solution by oral administration. Colitic control group showed a significant elevation in colon/body weight ratio, myeloperoxgidase activity, tumor necrosis factor, nitric oxide and malondialdehyde levels. However, glutathione level was reduced. It was found that the rutin-loaded hydrogel was more efficient than free rutin as evidenced by improvement of all measured parameters. These effects were confirmed histopathologically and may be attributed to its ability to control delivery of rutin to colon with minor early release of rutin before colon. The Poly(starch/acrylic acid) (1:10wt%) can represent a pivotal anti-inflammatory approach for patients with inflammatory bowel disease in order to increase efficacy and reduce toxicity.
Eight anthocyanidins, seven anthocyanins and two synthesized 4 0 -hydroxy flavyliums were examine... more Eight anthocyanidins, seven anthocyanins and two synthesized 4 0 -hydroxy flavyliums were examined as hydrogen donors to DPPH, ABTS and hydroxyl radicals, and as electron donors in the FRAP assay. Most compounds gave better activities than trolox and catechol. A structure-activity relationship (SAR) study showed that, in the absence of the 3-OH group, radicals of the 4, 5 or 7-OH groups can only be stabilized by resonance through pyrylium oxygen, while 3-OH group improved hydrogen atom donation because of the stabilization by anthocyanidin semiquinone-like resonance. Electron donation was also enhanced by the 3-OH group. Both anthocyanidins and their respective anthocyanins showed similar trends and close activities. Different types of sugar unit bonded to the 3-OH group or counter ion had minor effect on activities. The catechol structure improved both hydrogen and electron donation. Compounds lacking the catechol structure had a decreasing order of H-atom and electron donation (Mv > Pn > Pg > Ap > 4 0 -OH-flavylium) consistent with the decreasing number of their hydroxyl and/or methoxy groups.
The effects of five structurally variant amino acids, glycine, valine, methionine, phenylalanine ... more The effects of five structurally variant amino acids, glycine, valine, methionine, phenylalanine and cysteine were examined as inhibitors and/or stimulators of fresh-cut potato browning. The first four amino acids showed conflict effects; high concentrations (⩾100mM for glycine and ⩾1.0M for the other three amino acids) induced potato browning while lower concentrations reduced the browning process. Alternatively, increasing cysteine concentration consistently reduced the browning process due to reaction with quinone to give colorless adduct. In PPO assay, high concentrations (⩾1.11mM) of the four amino acids developed more color than that of control samples. Visible spectra indicated a continuous condensation of quinone and glycine to give colored adducts absorbed at 610-630nm which were separated and identified by LC-ESI-MS as catechol-diglycine adduct that undergoes polymerization with other glycine molecules to form peptide side chains. In lower concentrations, the less concentr...
... 6 BR James, Homogeneous Hydrogenation, Wiley, New York, 1973. 7 RE Harmon, SK Gupta and DJ Br... more ... 6 BR James, Homogeneous Hydrogenation, Wiley, New York, 1973. 7 RE Harmon, SK Gupta and DJ Brown, Chem. Rev., 73 (1973) 21. ... 6. BR James Homogeneous Hydrogenation, Wiley, New York (1973). 7. RE Harmon, SK Gupta and DJ Brown Chem. Rev. 73 (1973), p. 21. ...
Journal of Chromatography B: Biomedical Sciences and Applications, 1998
A simple, rapid, sensitive and selective HPLC method has been developed for the analysis of diaze... more A simple, rapid, sensitive and selective HPLC method has been developed for the analysis of diazepam (DZP) and its major metabolites, N-desmethyldiazepam (DMDZP), temazepam (TZP) and oxazepam (OZP), in plasma and urine, using clonazepam (CZP) as the internal standard and chloroform as the extracting solvent, with a 10 ng/ml limit of quantitation for the four assayed drugs, and an average (+/-S.D.) recovery of 87.7+/-6.46%, 92.9+/-5.31%, 91.4+/-4.01% and 91.7+/-2.68% for DZP, DMDZP, TZP and OZP, respectively (from plasma), and 89.6+/-2.26%, 90+/-4.24%, 87.45+/-0.64% and 94.50+/-0.71% for DZP, DMDZP, TZP and OZP, respectively (from urine). The method has also proved to be selective and reproducible.
The titled compounds were examined as PPO inhibitors and antibrowning agents; their various mecha... more The titled compounds were examined as PPO inhibitors and antibrowning agents; their various mechanisms were investigated and discussed. All compounds reduced significantly both the browning process and PPO activity. Browning index gave strong correlation with PPO activity (r 2 =0.96, n=19) indicating that the browning process is mainly enzymatic. Ascorbic acid could reduce the formed quinone instantly to the original substrate (catechol) at high concentration (>1.5 %) while at lower concentrations acted as competitive inhibitor (K I =0.256±0.067 mM). Cysteine, at higher concentrations (≥1.0 %), reacted with the resulted quinone to give a colorless products while at the low concentrations, cysteine worked as competitive inhibitor (K I = 1.113 ± 0.176 mM). Citric acid acted only as PPO non-competitive inhibitor with K I =2.074±0.363 mM. The products of PPOcatechole-cysteine reaction could be separation and identification by LC-ESI-MS. Results indicated that the product of the enzymatic oxidation of catechol, quinone, undergoes two successive nucleophilic attacks by cysteine thiol group. Cysteine was condensed with the resulted mono and dithiocatechols to form peptide side chains.
Commercial hydroxyethyl cellulose (HEC) was cyanoethylated with acrylonitrile in nonaqueous mediu... more Commercial hydroxyethyl cellulose (HEC) was cyanoethylated with acrylonitrile in nonaqueous medium in the presence of sodium hydroxide under a variety of conditions. Variables studied included the amount of acrylonitrile and the reaction temperature. The reaction was proved by NMR and its extent was measured by determining the nitrogen content. The physical properties of the obtained derivatives—i.e., the electric properties and
Searching for new organophosphorus compounds with minimum effects on acetylcholinesterase of non-... more Searching for new organophosphorus compounds with minimum effects on acetylcholinesterase of non-target organism especially mammals has gained an increased attention in the public concern. In this effort, the effects of some recently introduced O-ethyl ...
Anilinosilanes with different substituents on the benzene ring and on the silicon atom were prepa... more Anilinosilanes with different substituents on the benzene ring and on the silicon atom were prepared and used as antioxidants for lubricating base oil. The prepared antioxidants were compared with a commercial antioxidant termed MOX. The base oil before and after MOX addition ...
TiO2/benzoquinone hybrid films have been electrodeposited anodically from basic Ti(IV)-alkoxide s... more TiO2/benzoquinone hybrid films have been electrodeposited anodically from basic Ti(IV)-alkoxide solutions containing hydroquinone. The films were calcined at different temperatures between 350 and 550 °C and investigated in view of applications as photocatalyst and in dye-sensitized solar cells. Thermogravimetry analysis, differential thermo analysis, in situ X-ray diffraction, and transmission electron microscopy show the removal of the benzoquinone and starting crystallization of the TiO2 between 350 and 400 °C, followed by a further increase in the crystallinity and particle size with increasing calcination temperature, while the specific surface area is decreased due to an increasing pore size as confirmed by Kr adsorption measurements. In dye-sensitized solar cells, the higher crystallinity leads to an improved performance mainly due to improved adsorption of sensitizer dyes up to calcination temperatures of 500 °C, while all films exhibit good electron collection properties as investigated by intens...
The inhibitory effects of a recently introduced series of the titled compounds on insect and mamm... more The inhibitory effects of a recently introduced series of the titled compounds on insect and mammalian acetylcholinesterase (AChE) activity were examined, where the median inhibition concentration (I50) and the inhibition kinetic parameters, bimolecular inhibition ...
K. MAHMOODa, S. SABLEb, M. PAISb, HM ALP, A. HAMID A. HADP and E. GUITTETb aDepartment of Chemist... more K. MAHMOODa, S. SABLEb, M. PAISb, HM ALP, A. HAMID A. HADP and E. GUITTETb aDepartment of Chemistry, University of Malaya, 59 100 Kuala Lumpur, Malaysia. blnstitut de Chimie des Substances Naturelles, CNRS, 91 198 Gif-sur-Yvette, France. ... Abstract. - Cyathoviridine 2 was isolated from the bark of Cyathostemma viridiflorum Griff. and its structure elucidated by 2D NMR analysis. 2 showed cytotoxicity against KB cells (IC50 4.5 pg/ml). Key words. - Annonaceae, Cyathostemma, cyathoviridine. ... We have recently reported the structure of ...
Foliar application of profenofos was made onto potato plants 1 month before harvest. Determinatio... more Foliar application of profenofos was made onto potato plants 1 month before harvest. Determination of profenofos residues in fresh and processed potatoes was carried out. The detected levels were 11.48, 0.24, 0.22, 0.19, 0.004, and 0.16 mg/kg for fresh, frosen, microwave-baked, oven-baked, and french fried potatoes and potato peels, respectively. The profenofos residues induced the levels of transaminases (GOT and GPT). However, the GOT/GPT ratio was decreased. Little increase was observed in acid phosphatase (APase) activity
Artemisia judaica (ArJ) is a Mediterranean aromatic plant used traditionally to treat gastrointes... more Artemisia judaica (ArJ) is a Mediterranean aromatic plant used traditionally to treat gastrointestinal ailments, skin diseases, atherosclerosis, and as an immuno-stimulant. This study describes ArJ essential oil constituents and investigates their wound healing activity. The in vitro antioxidant and antibiofilm activities of ArJ essential oil were investigated. The in vivo pro/anti-inflammatory and oxidative/antioxidant markers were compared with standard silver sulfadiazine (SS) in a second-degree skin burn experimental rat model. The gas chromatography-equipped flame ionization detector (GC-FID) analysis of ArJ essential oil revealed the major classes of compounds as oxygenated monoterpenes (>57%) and cinnamic acid derivatives (18.03%). The antimicrobial tests of ArJ essential oil revealed that Bacillus cereus, Candida albicans, and Aspergillus niger were the most susceptible test organisms. Two second-degree burns (each 1 inch square in diameter) were created on the dorsum of ...
Chitosan hydrogels were prepared by gamma radiation grafting of acrylamide (AAm) onto chitosan (C... more Chitosan hydrogels were prepared by gamma radiation grafting of acrylamide (AAm) onto chitosan (CS). The gelation (%) increased as the AAm content was raised up to the CS/AAm ratio of 1/10 wt%. The grafting yield and the grafting ratios of the Poly(CS/AAm) hydrogel were found to be directly proportional to the increase in AAm contents. The swelling behavior was more pronounced with higher AAm content up to 1/15 wt% in the Poly(CS/AAm), and then decreased with further rise of the AAm content to 1/20 wt%, because of the formation of a highly crosslinked hydrogel, with high hydrogen bonding. The prepared Poly(CS/AAm) hydrogels were characterized by using FTIR, TGA and SEM techniques. The analysis confirmed successful preparation of Poly(CS/AAm) with different compositions. The adsorption capacity of the Poly(CS/AAm) hydrogel with the composition of (1:10 wt%) towards Nigrosin acid dye was found to be higher than that of the other hydrogel formulations. This may be due to the fact that the selected Poly(CS/AAm) hydrogel possesses a highly pronounced swelling behavior and a highly crosslinked structure, compared to the other prepared hydrogels. It has been also noted that the adsorption capacity of the 1:10 wt% Poly(CS/AAm) hydrogel enhanced markedly at pH 2, but decreased at higher pH values, namely, from pH 5 to pH 7.4. This can be explained by the protonation of amide groups of acrylamide and amine groups of chitosan occurring at lower pH. The high adsorption properties of the selected Poly(CS/AAm) hydrogel recommend it as a necessary bioremediation solution to face the high level of acid dye pollutants, such as Nigrosin, in industrial effluents.
The blending of polyvinyl alcohol (PVA) with starch with different content of citric acid as cros... more The blending of polyvinyl alcohol (PVA) with starch with different content of citric acid as crosslinker and glycerol as plasticizer were performed by casting method. The hydroxyl groups of PVA and Starch react with the citric acid (1 %) and glycerol (10 vol %) to form crosslinked network. The FTIR spectral analyses show the successful preparation of the different composition of the prepared PVA/ Starch /Citric acid/Glycerol bioblend films. It is found that the prepared PVA/ Starch /Citric acid/Glycerol with composition (2:1:1/10 vol %) bioblend film characterized by higher water resistance, good mechanical and higher thermal stability than other prepared bioblend films. The using of gamma radiation improved and modified water resistance property were the water uptake at equilibrium reduced remarkably at dose of 10 kGy. Also the thermal stability increased as irradiation dose increased up to dose of 30 kGy The improved mechanical and thermal properties of the selected PVA/ Starch /C...
Four halophytic plants, Lycium shawii, Anabasis articulata, Rumex vesicarius, and Zilla spinosa, ... more Four halophytic plants, Lycium shawii, Anabasis articulata, Rumex vesicarius, and Zilla spinosa, growing in the central Qassim area, Saudi Arabia, were phytochemically and biologically investigated. Their hydroalcoholic extracts’ UPLC-ESIQ-TOF analyses demonstrated the presence of 44 compounds of phenolic acids, flavonoids, saponins, carbohydrates, and fatty acids chemical classes. Among all the plants’ extracts, L. shawii showed the highest quantities of total phenolics, and flavonoids contents (52.72 and 13.01 mg/gm of the gallic acid and quercetin equivalents, respectively), along with the antioxidant activity in the TAA (total antioxidant activity), FRAP (ferric reducing antioxidant power), and DPPH-SA (2,2-diphenyl-1-picryl-hydrazyl-scavenging activity) assays with 25.6, 56.68, and 19.76 mg/gm, respectively, as Trolox equivalents. The hydroalcoholic extract of the L. shawii also demonstrated the best chelating activity at 21.84 mg/gm EDTA equivalents. Among all the four halophy...
International Journal of Environmental Science and Technology, 2016
Two fungi were isolated and examined to decolorize crystal violet dye, frequently used as textile... more Two fungi were isolated and examined to decolorize crystal violet dye, frequently used as textile dye and in microorganism staining, using basal salt medium under static condition at 30 °C. The more effective fungus gave less dry weight and lower pH indicating that the process was directed toward the decolorization process giving acidic products rather than microbial growth. The effective fungus was identified as Aspergillus niger and was used in the rest of experiments. Increasing the incubation period more than 10 days did not improve the decolorization process, while the best pH was 5.5. The decolorization process was effective (up to 84.6 %) with the examined range of dye concentrations (10–40 ppm). Sucrose content, as a carbon source, more than 1 % did not improve the decolorization process (80.9 %). Using ammonium sulfate as a nitrogen source, instead of sodium nitrate in the original basal medium, lowered the decolorization process, while using corn steep liquor enhanced the biodegradation up to 96.1 %. Although the dye violet color vanishes in acid medium because of decreasing the possibility of extending the benzene chromophore as a result of binding the nitrogen lone pair in the ammonium ion, the UV–Vis spectra and LC–MS–ESI analysis of the bioassay products proved that the decolorization is due to the biodegradation of the dye rather than the resonance factor in acidic medium or biosorption by fungus mycelia.
International Journal of Biological Macromolecules, 2016
The copolymerization of starch with acrylic acid AAc using direct gamma radiation technique was p... more The copolymerization of starch with acrylic acid AAc using direct gamma radiation technique was performed. The effect of AAc concentrations on the gel (%) and swelling behavior were investigated. It is found that as AAc concentrations increase both gel(%) and swelling behavior increase. The Poly(starch/acrylic acid) (1:10wt%) hydrogel were selected due to its high swelling properties. From the in-vitro release study of the rutin-loaded hydrogel it is observed that it is strong pH-dependent release behavior, thus offering a maximum release as pH increased. The dextran sulphate sodium (DSS)-induced rat colitis model was treated with rutin-loaded Poly(starch/acrylic acid) (1:10wt%) hydrogel and free rutin solution by oral administration. Colitic control group showed a significant elevation in colon/body weight ratio, myeloperoxgidase activity, tumor necrosis factor, nitric oxide and malondialdehyde levels. However, glutathione level was reduced. It was found that the rutin-loaded hydrogel was more efficient than free rutin as evidenced by improvement of all measured parameters. These effects were confirmed histopathologically and may be attributed to its ability to control delivery of rutin to colon with minor early release of rutin before colon. The Poly(starch/acrylic acid) (1:10wt%) can represent a pivotal anti-inflammatory approach for patients with inflammatory bowel disease in order to increase efficacy and reduce toxicity.
Eight anthocyanidins, seven anthocyanins and two synthesized 4 0 -hydroxy flavyliums were examine... more Eight anthocyanidins, seven anthocyanins and two synthesized 4 0 -hydroxy flavyliums were examined as hydrogen donors to DPPH, ABTS and hydroxyl radicals, and as electron donors in the FRAP assay. Most compounds gave better activities than trolox and catechol. A structure-activity relationship (SAR) study showed that, in the absence of the 3-OH group, radicals of the 4, 5 or 7-OH groups can only be stabilized by resonance through pyrylium oxygen, while 3-OH group improved hydrogen atom donation because of the stabilization by anthocyanidin semiquinone-like resonance. Electron donation was also enhanced by the 3-OH group. Both anthocyanidins and their respective anthocyanins showed similar trends and close activities. Different types of sugar unit bonded to the 3-OH group or counter ion had minor effect on activities. The catechol structure improved both hydrogen and electron donation. Compounds lacking the catechol structure had a decreasing order of H-atom and electron donation (Mv > Pn > Pg > Ap > 4 0 -OH-flavylium) consistent with the decreasing number of their hydroxyl and/or methoxy groups.
The effects of five structurally variant amino acids, glycine, valine, methionine, phenylalanine ... more The effects of five structurally variant amino acids, glycine, valine, methionine, phenylalanine and cysteine were examined as inhibitors and/or stimulators of fresh-cut potato browning. The first four amino acids showed conflict effects; high concentrations (⩾100mM for glycine and ⩾1.0M for the other three amino acids) induced potato browning while lower concentrations reduced the browning process. Alternatively, increasing cysteine concentration consistently reduced the browning process due to reaction with quinone to give colorless adduct. In PPO assay, high concentrations (⩾1.11mM) of the four amino acids developed more color than that of control samples. Visible spectra indicated a continuous condensation of quinone and glycine to give colored adducts absorbed at 610-630nm which were separated and identified by LC-ESI-MS as catechol-diglycine adduct that undergoes polymerization with other glycine molecules to form peptide side chains. In lower concentrations, the less concentr...
... 6 BR James, Homogeneous Hydrogenation, Wiley, New York, 1973. 7 RE Harmon, SK Gupta and DJ Br... more ... 6 BR James, Homogeneous Hydrogenation, Wiley, New York, 1973. 7 RE Harmon, SK Gupta and DJ Brown, Chem. Rev., 73 (1973) 21. ... 6. BR James Homogeneous Hydrogenation, Wiley, New York (1973). 7. RE Harmon, SK Gupta and DJ Brown Chem. Rev. 73 (1973), p. 21. ...
Journal of Chromatography B: Biomedical Sciences and Applications, 1998
A simple, rapid, sensitive and selective HPLC method has been developed for the analysis of diaze... more A simple, rapid, sensitive and selective HPLC method has been developed for the analysis of diazepam (DZP) and its major metabolites, N-desmethyldiazepam (DMDZP), temazepam (TZP) and oxazepam (OZP), in plasma and urine, using clonazepam (CZP) as the internal standard and chloroform as the extracting solvent, with a 10 ng/ml limit of quantitation for the four assayed drugs, and an average (+/-S.D.) recovery of 87.7+/-6.46%, 92.9+/-5.31%, 91.4+/-4.01% and 91.7+/-2.68% for DZP, DMDZP, TZP and OZP, respectively (from plasma), and 89.6+/-2.26%, 90+/-4.24%, 87.45+/-0.64% and 94.50+/-0.71% for DZP, DMDZP, TZP and OZP, respectively (from urine). The method has also proved to be selective and reproducible.
The titled compounds were examined as PPO inhibitors and antibrowning agents; their various mecha... more The titled compounds were examined as PPO inhibitors and antibrowning agents; their various mechanisms were investigated and discussed. All compounds reduced significantly both the browning process and PPO activity. Browning index gave strong correlation with PPO activity (r 2 =0.96, n=19) indicating that the browning process is mainly enzymatic. Ascorbic acid could reduce the formed quinone instantly to the original substrate (catechol) at high concentration (>1.5 %) while at lower concentrations acted as competitive inhibitor (K I =0.256±0.067 mM). Cysteine, at higher concentrations (≥1.0 %), reacted with the resulted quinone to give a colorless products while at the low concentrations, cysteine worked as competitive inhibitor (K I = 1.113 ± 0.176 mM). Citric acid acted only as PPO non-competitive inhibitor with K I =2.074±0.363 mM. The products of PPOcatechole-cysteine reaction could be separation and identification by LC-ESI-MS. Results indicated that the product of the enzymatic oxidation of catechol, quinone, undergoes two successive nucleophilic attacks by cysteine thiol group. Cysteine was condensed with the resulted mono and dithiocatechols to form peptide side chains.
Commercial hydroxyethyl cellulose (HEC) was cyanoethylated with acrylonitrile in nonaqueous mediu... more Commercial hydroxyethyl cellulose (HEC) was cyanoethylated with acrylonitrile in nonaqueous medium in the presence of sodium hydroxide under a variety of conditions. Variables studied included the amount of acrylonitrile and the reaction temperature. The reaction was proved by NMR and its extent was measured by determining the nitrogen content. The physical properties of the obtained derivatives—i.e., the electric properties and
Searching for new organophosphorus compounds with minimum effects on acetylcholinesterase of non-... more Searching for new organophosphorus compounds with minimum effects on acetylcholinesterase of non-target organism especially mammals has gained an increased attention in the public concern. In this effort, the effects of some recently introduced O-ethyl ...
Anilinosilanes with different substituents on the benzene ring and on the silicon atom were prepa... more Anilinosilanes with different substituents on the benzene ring and on the silicon atom were prepared and used as antioxidants for lubricating base oil. The prepared antioxidants were compared with a commercial antioxidant termed MOX. The base oil before and after MOX addition ...
TiO2/benzoquinone hybrid films have been electrodeposited anodically from basic Ti(IV)-alkoxide s... more TiO2/benzoquinone hybrid films have been electrodeposited anodically from basic Ti(IV)-alkoxide solutions containing hydroquinone. The films were calcined at different temperatures between 350 and 550 °C and investigated in view of applications as photocatalyst and in dye-sensitized solar cells. Thermogravimetry analysis, differential thermo analysis, in situ X-ray diffraction, and transmission electron microscopy show the removal of the benzoquinone and starting crystallization of the TiO2 between 350 and 400 °C, followed by a further increase in the crystallinity and particle size with increasing calcination temperature, while the specific surface area is decreased due to an increasing pore size as confirmed by Kr adsorption measurements. In dye-sensitized solar cells, the higher crystallinity leads to an improved performance mainly due to improved adsorption of sensitizer dyes up to calcination temperatures of 500 °C, while all films exhibit good electron collection properties as investigated by intens...
The inhibitory effects of a recently introduced series of the titled compounds on insect and mamm... more The inhibitory effects of a recently introduced series of the titled compounds on insect and mammalian acetylcholinesterase (AChE) activity were examined, where the median inhibition concentration (I50) and the inhibition kinetic parameters, bimolecular inhibition ...
K. MAHMOODa, S. SABLEb, M. PAISb, HM ALP, A. HAMID A. HADP and E. GUITTETb aDepartment of Chemist... more K. MAHMOODa, S. SABLEb, M. PAISb, HM ALP, A. HAMID A. HADP and E. GUITTETb aDepartment of Chemistry, University of Malaya, 59 100 Kuala Lumpur, Malaysia. blnstitut de Chimie des Substances Naturelles, CNRS, 91 198 Gif-sur-Yvette, France. ... Abstract. - Cyathoviridine 2 was isolated from the bark of Cyathostemma viridiflorum Griff. and its structure elucidated by 2D NMR analysis. 2 showed cytotoxicity against KB cells (IC50 4.5 pg/ml). Key words. - Annonaceae, Cyathostemma, cyathoviridine. ... We have recently reported the structure of ...
Foliar application of profenofos was made onto potato plants 1 month before harvest. Determinatio... more Foliar application of profenofos was made onto potato plants 1 month before harvest. Determination of profenofos residues in fresh and processed potatoes was carried out. The detected levels were 11.48, 0.24, 0.22, 0.19, 0.004, and 0.16 mg/kg for fresh, frosen, microwave-baked, oven-baked, and french fried potatoes and potato peels, respectively. The profenofos residues induced the levels of transaminases (GOT and GPT). However, the GOT/GPT ratio was decreased. Little increase was observed in acid phosphatase (APase) activity
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