Epoxide hydrolase (EC 3.3.2.3) purified from rat liver microsomes has been immobilized by covalen... more Epoxide hydrolase (EC 3.3.2.3) purified from rat liver microsomes has been immobilized by covalent linking to dextran activated by imidazolyl carbamate groups, under mild conditions. K app m values of free and dextran bound epoxide hydrolase toward benzo(a)pyrene-4,5-oxide ...
Chromatographic separation of a 70% aqueous methanol extract (AME) of Pongamia pinnata (Linn.) Pi... more Chromatographic separation of a 70% aqueous methanol extract (AME) of Pongamia pinnata (Linn.) Pierre (Leguminosae) leaves has led to the isolation of two new isoflavonoid diglycosides, 4'-O-methyl-genistein 7-O-beta-D-rutinoside (2) and 2',5'-dimethoxy-genistein 7-O-beta-D-apiofuranosyl-(1"'-->6")-O-beta-D-glucopyranoside (6), and a new rotenoid, 12a-hydroxy-alpha-toxicarol (5), together with nine known metabolites, vecinin-2 (1), kaempferol 3-O-beta-D-rutinoside (3), rutin (4), vitexin (7), isoquercitrin (8), kaempferol 3-O-beta-D-glucopyranoside (9), 11,12a-dihydroxy-munduserone (10), kaempferol (11), and quercetin (12). Their structures were elucidated on the basis of chemical and spectroscopic analyses.
Chromatographic separation of a 70% aqueous methanol extract (AME) of Pongamia pinnata (Linn.) Pi... more Chromatographic separation of a 70% aqueous methanol extract (AME) of Pongamia pinnata (Linn.) Pierre (Leguminosae) leaves has led to the isolation of two new isoflavonoid diglycosides, 4'-O-methyl-genistein 7-O-beta-D-rutinoside (2) and 2',5'-dimethoxy-genistein 7-O-beta-D-apiofuranosyl-(1"'-->6")-O-beta-D-glucopyranoside (6), and a new rotenoid, 12a-hydroxy-alpha-toxicarol (5), together with nine known metabolites, vecinin-2 (1), kaempferol 3-O-beta-D-rutinoside (3), rutin (4), vitexin (7), isoquercitrin (8), kaempferol 3-O-beta-D-glucopyranoside (9), 11,12a-dihydroxy-munduserone (10), kaempferol (11), and quercetin (12). Their structures were elucidated on the basis of chemical and spectroscopic analyses.
Rumex dentatus L. and Rumex vesicarius L., of the family Polygonaceae, are edible herbs growing w... more Rumex dentatus L. and Rumex vesicarius L., of the family Polygonaceae, are edible herbs growing wild in Egypt. Their lipoid constituents were examined by both liquid chromatography/mass spectrometry (LC/MS) and by gas chromatography/mass spectrometry (GC/MS). Their essential oil compositions consisted mainly of thujene, limonene, fenchon, estragole, and anethole but at largely different concentration. Fatty acid compositions were similar among the two species and consisting of palmitic, oleic, linoleic and linolenic acids, with R. vesicarius containing much higher level of omega-3-fatty acids. Both of the crude lipid extracts of the two species showed strong antioxidant activity as a radical quenching agent against 2,2-diphenyl-1-picrylhydrazyl (DPPH) systems. Antioxidant activities were mostly associated with the polar lipid fractions. High performance thin layer chromatography (HPTLC), both in the normal and reversed phase,as well as liquid chromatography/mass spectrometry (LC/MS) in the positive and negative electrospray ionization (ESI), showed unique chemical profile for each species that can be useful for species identification and quality control of herbal drug formulations. R. vesicarius was characterized by abundances of flavonoids and R. dentatus was abundant in anthraquinones and chromones.
Stability indicating assays for determination of Donepezil Hydrochloride in presence of its oxida... more Stability indicating assays for determination of Donepezil Hydrochloride in presence of its oxidative degradate were developed and validated. The first three are spectrophotometric methods depending on using zero order (D(0)), first order (D(1)) and second order (D(2)) spectra. The absorbance was measured at 315 nm for (D(0)) while the amplitude was measured at 332.1nm for (D(1)) and 340 nm for (D(2)) using deionized water as a solvent. Donepezil Hydrochloride (I) can be determined in the presence of up to 70% of its oxidative degradate (II) using (D(0)), 80% using (D(1)) and 90% using (D(2)). The linearity range was found to be 8-56 microg ml(-1) for (D(0)), (D(1)) and (D(2)). These methods were applied for the analysis of I in both powder and tablet form. Also, a spectrofluorimetric method depending on measuring the native fluorescence of I in deionized water using lambda excitation 226 nm and lambda emission 391 nm is suggested. The linearity range was found to be 0.32-3.20 microg ml(-1) using this method, I was determined in the presence of up to 90% of II. The proposed method was applied for the analysis of I in tablet form as well as in human plasma. The last method depends on using TLC separation of I from its oxidative degradate II and I was then determined spectrodensitometrically. The mobile phase was methanol : chloroform : 25% ammonia (16 : 64 : 0.1 by volume). The linearity range was found to be 2-15 microg/spot. This method was applied to the analysis of I in both powder and tablet form using acetonitrile as a solvent.
Objectives: This work aimed to isolate phenolic compounds from the stems of Schinus molle and eva... more Objectives: This work aimed to isolate phenolic compounds from the stems of Schinus molle and evaluate its antibacterial and anti-microalgae (phycotoxic) activity. Methods: 80% MeOH extract of stems of Schinus molle was subjected to chromatographic separation, structures of the isolated compounds were established by different chromatographic and spectral techniques UV, MS, 1 H and 13 C NMR. Anti-bacterial and anti-microalgal activity was evaluated by agar diffusion method. Results: Four known phenolic compounds were isolated for the first time from the genus Schinus viz, chlorogenic methyl ester 4, quercitrin 2″-O-caffeate 6, quercetin 3′-O-α-L-1 C 4 -rhamnopyranoside 10 and rhamnetin-3-O-β-D-4 C 1 -galactopyranoside 11. Also four known quercetin glycosides viz, hyperin 6"-O-gallate 5, quercetin 3-O-β-D-galacturonopyranoside 7, isoquercitrin 8 and hyperin 9 together with gallic acid 1, methyl gallate 2, chlorogenic acid 3 and the free quercetin aglycone 12, were obtained from t...
Epoxide hydrolase (EC 3.3.2.3) purified from rat liver microsomes has been immobilized by covalen... more Epoxide hydrolase (EC 3.3.2.3) purified from rat liver microsomes has been immobilized by covalent linking to dextran activated by imidazolyl carbamate groups, under mild conditions. K app m values of free and dextran bound epoxide hydrolase toward benzo(a)pyrene-4,5-oxide ...
Chromatographic separation of a 70% aqueous methanol extract (AME) of Pongamia pinnata (Linn.) Pi... more Chromatographic separation of a 70% aqueous methanol extract (AME) of Pongamia pinnata (Linn.) Pierre (Leguminosae) leaves has led to the isolation of two new isoflavonoid diglycosides, 4'-O-methyl-genistein 7-O-beta-D-rutinoside (2) and 2',5'-dimethoxy-genistein 7-O-beta-D-apiofuranosyl-(1"'-->6")-O-beta-D-glucopyranoside (6), and a new rotenoid, 12a-hydroxy-alpha-toxicarol (5), together with nine known metabolites, vecinin-2 (1), kaempferol 3-O-beta-D-rutinoside (3), rutin (4), vitexin (7), isoquercitrin (8), kaempferol 3-O-beta-D-glucopyranoside (9), 11,12a-dihydroxy-munduserone (10), kaempferol (11), and quercetin (12). Their structures were elucidated on the basis of chemical and spectroscopic analyses.
Chromatographic separation of a 70% aqueous methanol extract (AME) of Pongamia pinnata (Linn.) Pi... more Chromatographic separation of a 70% aqueous methanol extract (AME) of Pongamia pinnata (Linn.) Pierre (Leguminosae) leaves has led to the isolation of two new isoflavonoid diglycosides, 4'-O-methyl-genistein 7-O-beta-D-rutinoside (2) and 2',5'-dimethoxy-genistein 7-O-beta-D-apiofuranosyl-(1"'-->6")-O-beta-D-glucopyranoside (6), and a new rotenoid, 12a-hydroxy-alpha-toxicarol (5), together with nine known metabolites, vecinin-2 (1), kaempferol 3-O-beta-D-rutinoside (3), rutin (4), vitexin (7), isoquercitrin (8), kaempferol 3-O-beta-D-glucopyranoside (9), 11,12a-dihydroxy-munduserone (10), kaempferol (11), and quercetin (12). Their structures were elucidated on the basis of chemical and spectroscopic analyses.
Rumex dentatus L. and Rumex vesicarius L., of the family Polygonaceae, are edible herbs growing w... more Rumex dentatus L. and Rumex vesicarius L., of the family Polygonaceae, are edible herbs growing wild in Egypt. Their lipoid constituents were examined by both liquid chromatography/mass spectrometry (LC/MS) and by gas chromatography/mass spectrometry (GC/MS). Their essential oil compositions consisted mainly of thujene, limonene, fenchon, estragole, and anethole but at largely different concentration. Fatty acid compositions were similar among the two species and consisting of palmitic, oleic, linoleic and linolenic acids, with R. vesicarius containing much higher level of omega-3-fatty acids. Both of the crude lipid extracts of the two species showed strong antioxidant activity as a radical quenching agent against 2,2-diphenyl-1-picrylhydrazyl (DPPH) systems. Antioxidant activities were mostly associated with the polar lipid fractions. High performance thin layer chromatography (HPTLC), both in the normal and reversed phase,as well as liquid chromatography/mass spectrometry (LC/MS) in the positive and negative electrospray ionization (ESI), showed unique chemical profile for each species that can be useful for species identification and quality control of herbal drug formulations. R. vesicarius was characterized by abundances of flavonoids and R. dentatus was abundant in anthraquinones and chromones.
Stability indicating assays for determination of Donepezil Hydrochloride in presence of its oxida... more Stability indicating assays for determination of Donepezil Hydrochloride in presence of its oxidative degradate were developed and validated. The first three are spectrophotometric methods depending on using zero order (D(0)), first order (D(1)) and second order (D(2)) spectra. The absorbance was measured at 315 nm for (D(0)) while the amplitude was measured at 332.1nm for (D(1)) and 340 nm for (D(2)) using deionized water as a solvent. Donepezil Hydrochloride (I) can be determined in the presence of up to 70% of its oxidative degradate (II) using (D(0)), 80% using (D(1)) and 90% using (D(2)). The linearity range was found to be 8-56 microg ml(-1) for (D(0)), (D(1)) and (D(2)). These methods were applied for the analysis of I in both powder and tablet form. Also, a spectrofluorimetric method depending on measuring the native fluorescence of I in deionized water using lambda excitation 226 nm and lambda emission 391 nm is suggested. The linearity range was found to be 0.32-3.20 microg ml(-1) using this method, I was determined in the presence of up to 90% of II. The proposed method was applied for the analysis of I in tablet form as well as in human plasma. The last method depends on using TLC separation of I from its oxidative degradate II and I was then determined spectrodensitometrically. The mobile phase was methanol : chloroform : 25% ammonia (16 : 64 : 0.1 by volume). The linearity range was found to be 2-15 microg/spot. This method was applied to the analysis of I in both powder and tablet form using acetonitrile as a solvent.
Objectives: This work aimed to isolate phenolic compounds from the stems of Schinus molle and eva... more Objectives: This work aimed to isolate phenolic compounds from the stems of Schinus molle and evaluate its antibacterial and anti-microalgae (phycotoxic) activity. Methods: 80% MeOH extract of stems of Schinus molle was subjected to chromatographic separation, structures of the isolated compounds were established by different chromatographic and spectral techniques UV, MS, 1 H and 13 C NMR. Anti-bacterial and anti-microalgal activity was evaluated by agar diffusion method. Results: Four known phenolic compounds were isolated for the first time from the genus Schinus viz, chlorogenic methyl ester 4, quercitrin 2″-O-caffeate 6, quercetin 3′-O-α-L-1 C 4 -rhamnopyranoside 10 and rhamnetin-3-O-β-D-4 C 1 -galactopyranoside 11. Also four known quercetin glycosides viz, hyperin 6"-O-gallate 5, quercetin 3-O-β-D-galacturonopyranoside 7, isoquercitrin 8 and hyperin 9 together with gallic acid 1, methyl gallate 2, chlorogenic acid 3 and the free quercetin aglycone 12, were obtained from t...
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