Ahmed M Zaghloul | Mansoura University (original) (raw)

Papers by Ahmed M Zaghloul

Zeitschrift fur Naturforschung. C, Journal of biosciences, Jan 8, 2016

An indole alkaloid, 2-(5-hydroxy-1H-indol-3-yl)-2-oxo-acetic acid (1) isolated for the first time... more An indole alkaloid, 2-(5-hydroxy-1H-indol-3-yl)-2-oxo-acetic acid (1) isolated for the first time from nature, in addition to the nine known compounds 5-hydroxy-1H-indole-3-carboxylic acid methyl ester (2), alocasin B (3), hyrtiosin B (4), α-monopalmitin (5), 1-O-β-D-glucopyranosyl-(2S, 3R, 4E, 8Z)-2-[(2(R)-hydroctadecanoyl) amido]-4,8-octadecadiene-1,3-diol (6), 3-epi-betulinic acid (7), 3-epi-ursolic acid (8), β-sitosterol (9) and β-sitosterol 3-O-β-D-glucoside (10) were isolated from the rhizomes of Alocasia macrorrhiza (Araceae). Their structures were elucidated by 1D and 2D NMR spectroscopic data. Of these compounds, 6 exhibited the strongest cytotoxicity against the four tested human cancer cell lines (IC50 of about 10 µM against Hep-2 larynx cancer cells).

Planta Medica, 1991

homonuclear NMR, namely ROESY (6), and long range heteronuclear correlation] methods. It is inter... more homonuclear NMR, namely ROESY (6), and long range heteronuclear correlation] methods. It is interesting to note that crenatoside (1) is the first phenylpropanoid glycoside that contains, besides the glycosidic linkage, an ether linkage between a glucose moiety and a 3,4-dihydroxyphenylethanol moiety. References

Zagazig Journal of Pharmaceutical Sciences, Dec 1, 2002

Life Sciences, 2022

Aim Liver cirrhosis is the result of a vicious cycle of both chronic oxidative stress and inflamm... more Aim Liver cirrhosis is the result of a vicious cycle of both chronic oxidative stress and inflammation. NADPH oxidase-4 (NOX4) and its companion, NOD-like receptor protein 3 (NLRP3) inflammasome, are emerging as therapeutic targets of liver fibrosis. MAIN METHODS Baicalin (BA), a natural flavone, has been investigated for its therapeutic potential against cirrhosis induced by thioacetamide (TAA) (200 mg/kg, twice/week) for 12 weeks in Sprague-Dawley rats. Two doses of BA were administered (25 and 75 mg/kg/day, orally, a week after TAA was stopped and continued for 4 weeks). KEY FINDINGS BA was able to reduce fibrosis visualized by Masson trichrome and immunohistochemical staining of the hepatic α-smooth muscle actin (α-SMA) and transforming growth factor-β1. Moreover, BA was able to ameliorate inflammation by reducing hepatic NLRP3 inflammasome subunits, NLRP3 and caspase-1, both parts of the complex responsible for the activation of different interleukins (IL), measured as IL-1β. In addition, BA was able to reduce hepatic nuclear factor kappa B (NF-κB)-driven inflammation through IL-6. BA targeted inflammation through its anti-oxidant ability evidenced by the enhancement of the hepatic superoxide dismutase (SOD) and reduced glutathione (GSH) activity and level, respectively, and the reduction of both hepatic malondialdehyde (MDA) and nitric oxide (NOx) contents. Treatment with BA significantly decreased TAA-induced elevation in hepatic NOX4, a key enzyme for reactive oxygen species (ROS) generation, as well as, inducible nitric oxide synthase (iNOS). SIGNIFICANCE therefore, the study could conclude, the anti-fibrotic effect of BA through TGF- β1/NOX4/NF-κB/NLRP3 pathway, exerting both anti-inflammatory and anti-oxidant effects.

A new homoisoflavan, identified as (3 R)-7-hydroxy-3′,4′-methylenedioxyhomoiso... more A new homoisoflavan, identified as (3 R)-7-hydroxy-3′,4′-methylenedioxyhomoisoflavan, was isolated from Dracaena cinnabari Balf. f. resin. The structure was elucidated by one- and two-dimensional NMR spectroscopy as well as high resolution mass spectrometry. In addition, a diverse group of flavonoids were isolated, representing homoisoflavans, flavans, flavanones, chalcones and dihydrochalcones. The compounds were evaluated for their α-glucosidase and COX-II inhibition activity. The obtained IC50 values of the tested flavonoids gave an insight about some key structural features to their α-glucosidase and COX-II inhibitory activity. For α-glucosidase inhibitory activity, a flavanone skeleton was favorable over a flavan. For COX-II inhibition, the introduction of a fused heterocyclic ring at the homoisoflavan skeleton enhanced the activity.

Natural Product Research, 2021

Abstract A new homoisoflavan, identified as (3 R)-7-hydroxy-3′,4′-methylenedioxyhomoisoflavan, wa... more Abstract A new homoisoflavan, identified as (3 R)-7-hydroxy-3′,4′-methylenedioxyhomoisoflavan, was isolated from Dracaena cinnabari Balf. f. resin. The structure was elucidated by one- and two-dimensional NMR spectroscopy as well as high resolution mass spectrometry. In addition, a diverse group of flavonoids were isolated, representing homoisoflavans, flavans, flavanones, chalcones and dihydrochalcones. The compounds were evaluated for their α-glucosidase and COX-II inhibition activity. The obtained IC50 values of the tested flavonoids gave an insight about some key structural features to their α-glucosidase and COX-II inhibitory activity. For α-glucosidase inhibitory activity, a flavanone skeleton was favorable over a flavan. For COX-II inhibition, the introduction of a fused heterocyclic ring at the homoisoflavan skeleton enhanced the activity.

Egyptian journal of pharmaceutical sciences, 1990

Cadherins play pivotal roles in the toxicity of Bacillus thuringiensis Cry proteins. Here I teste... more Cadherins play pivotal roles in the toxicity of Bacillus thuringiensis Cry proteins. Here I tested and showed that an Aedes cadherin (AAEL007478) and an N-cadherin (AAEL000597) are involved in the in vivo toxicity of Cry11A toxin to Aedes aegypti. Aedes cadherin was stably expressed in a mosquito cell line and these cells showed increased sensitivity (37% death) to Cry11Aa toxin. These results show Aedes cadherin mediates Cry11Aa toxicity, but since high toxicity was not obtained, an additional secondary receptor may be needed for manifestation of full toxicity. Using a whole genome screen to identify genes that are altered during Cry11Aa intoxication, I identified an N-cadherin gene (AAEL000597) that was significantly down-regulated. An EGF-LamG fragment from this N-cadherin bound Cry11Aa with high affinity and competed with Cry11Aa binding to mosquito midgut membranes. Moreover, Ncadherin-silenced mosquitoes showed tolerance to Cry11Aa, implying that this cadherin is involved in mediating Cry11Aa toxicity. I also showed that this N-cadherin interacts with an amino acid on loop α-8 of Cry11Aa, which is different from that which interacts vii with the Aedes cadherin binding region. These data suggest that Cry11Aa probably has two different pathogenic pathways that act through two different cadherins in Ae. aegypti. I also established a Cry11A-resistant strain to determine which mode of action is involved in Aedes Cry11Aa resistance. Brush border membranes from this strain (G30) bound Cry11Aa less compared to the binding in the wild type (WT), implying Cry11Aa resistance resulted from altered receptor binding affinity, but not proteolytic activity since no change in the latter was observed. Using RNA-seq analyses, immunoblot assays and mass spectrometry, we found the N-cadherin (AAEL000597) and an alkaline phosphatase (ALP, AAEL003298) were down-regulated in Cry11A-resistant larvae midgut. These results strongly suggest that N-cadherin and ALP are associated with Cry11Aa resistance in Ae. aegypti. In summary, based on data in the literature and my work, I demonstrate that two different pathways of Cry11Aa toxicity are possible; one involving an N-cadherin and the other a combination of Aedes cadherin and an ALP in Ae. aegypti. Moreover, Ncadherin and ALP not only mediate Cry11Aa toxicity, but they were appear to be associated with Cry11Aa resistance. ALP has been proposed as a secondary receptor mediating Cry11Aa toxicity with Aedes cadherin, and hence attenuation of its expression can lead to Cry11A resistance. viii

Indian Journal of Science and Technology, 2020

Objectives: Searching for new antiviral compounds is important due to continuous appearance of ne... more Objectives: Searching for new antiviral compounds is important due to continuous appearance of new viral strains that resist the commonly used drugs and due to toxic side effects of some of these drugs. This current study was designed to investigate some herbs to discover new natural antiviral agents. Methods: Eight herbal extracts were screened for antiviral activities against Hepatitis A, Herpes Simplex-1 and Coxsackie viruses. Bio guided fractionation of the active extracts using different solvents and further investigation of the bioactive one using various chromatographic techniques including normal phase column chromatography, poly amide column and preparative TLC led to isolation and identification of twelve compounds. Structural elucidation of these compounds was done using different spectroscopic techniques including IR, HR-MS, 1D and 2D-NMR. The antiviral activities of the isolated compounds were assessed by MTT assay that depends on mixed treatment assay which test inactivation of virus particles in the virus suspension by samples. The concentration of samples which inactivate virus particles in virus suspension by 50% compared with untreated control was determined for each sample and was compared with IC 50 of positive control, Acyclovir. Findings: Twelve known compounds were isolated from the bioactive fractions of Cleome droserifolia and Lotus creticus. Nine compounds (1-9) from methylene chloride and ethyl acetate fractions of Cleome droserifolia and four compounds (10-13) from ethyl acetate and butanol fractions of Lotus creticus. Teuclatriol (4) was the most potent, with IC 50 value of 4.89 ±0.061µM against HSV-1 and a selective index (SI) value of 4.8. Moreover, the pentamethoxyflavone (3) was the most active against HAV with IC 50 value of 9.52±0.329 µM and SI of 3.4. The potent activity against Cox. B4 virus with IC 50 of 13.054 ±0.348 µM and SI of 3.4 exhibited by β-sitosterol 3-O-β-D-glucoside (6, 12). Novelty: The results highlight that these compounds are candidates for the development of new lead antiviral compounds. This is the first report for proving antiviral activities of these compounds.

South African Journal of Botany

Journal of Essential Oil Bearing Plants

Natural Product Research

A new Clinked chalcone-dihydrochalcone dimer, named dracidione, was isolated from the ethyl aceta... more A new Clinked chalcone-dihydrochalcone dimer, named dracidione, was isolated from the ethyl acetate extract of dragon's blood resin of Dracaena cinnabari Balf. f. Structure elucidation of the new compound was carried out by means of one-and two-dimensional NMR spectroscopy in addition to high resolution mass spectrometry. The unique structure incorporated a chalcone and a dihydrochalcone, which is reported for the first time from nature. Furthermore, dracidione showed moderate α-glucosidase inhibitory activity with IC 50 = 40.27 µg/ml.

Natural Product Sciences

The root-knot nematode, Meloidogyne incognita caused a serious damage to many plants. The phenoli... more The root-knot nematode, Meloidogyne incognita caused a serious damage to many plants. The phenolic components of the leaves of Schinus terebinthifolius were investigated as potential nematicidal agents for M. incognita. Nine compounds were isolated and characterized as viz., 1,2,3,4,6-pentagalloyl glucose (1), kaempferol-3-O-α-L-rhamnoside (Afzelin) (2), quercetin-3-O-α-L-rhamnoside (Quercetrin) (3), myricetin (4), myricetin-3-O-α-L-rhamnoside (Myricetrin) (5), methylgallate (6), protocatechuic acid (7), quercetin (8), and gallic acid (9) using nuclear magnetic resonance (NMR) spectroscopy. Compound 1 showed pronounced nematicidal activity compared to Oxamyl as a positive control. It showed the lowest eggs-hatchability (34%) and the highest mortality in nematode population (21% after 72 hours of treatment) at a concentration of 200 μg/mL. It exhibited the best suppressed total nematode population, root galling and number of eggmasses in infected tomato plants. The total carbohydrates and proteins were also significantly induced by 1 with reduction in total phenolics and increase in defense-related proteins. Thus, compound 1 could be a promising, more safe and effective natural nematicidal agent for the control of root-knot nematodes.

Phytochemistry, 1983

ABSTRACT Two further guaianolides were isolated from the aerial parts of Arctotis grandis.

Zeitschrift Fur Naturforschung C, 2008

8-beta-Hydroxypimar-15-en-19-oic acid (1), taxodione (2), 6,7-dehydro-8-hydrotaxodone (3), querce... more 8-beta-Hydroxypimar-15-en-19-oic acid (1), taxodione (2), 6,7-dehydro-8-hydrotaxodone (3), quercetin-3-O-beta-D-glucopyranoside (4), and shikimic acid (5) were isolated from the leaves of Taxodium distichum L. (Rich.) for the first time. Previously reported compounds [beta-sitosterol (6), isorhamnetin (7), quercetin (8), isorhamnetin-3-O-alpha-arabinofuranoside (9), quercetin-3-O-a-arabinofuranoside (10)] have also been isolated. The activity of taxodione as an inhibitor for hepatic stellate cells was determined. The antitumour activity of 2, 3, and 5 using a DNA affinity probe was examined.

A polyherbal formulation (PHF)consisting of Boswellia sacra gum, Nigella sativa L. seeds and Hord... more A polyherbal formulation (PHF)consisting of Boswellia sacra gum, Nigella sativa L. seeds and Hordium vulgare is used in folk medicine in Kingdom of Saudi Arabia for treatment of diabetes. The acute toxicity, median lethal dose (LD50), antidiabetic activity, liver and kidney function markers of each component as well as the PHF were evaluated. The highest antidiabetic activity was noticed with Boswellia sacra gum and the PHF. While Nigella sativa L. afforded moderate activity followed by Hordium vulgare. Liver and kidney functions did not altered by administration of any of the tested samples. Furthermore, some quality control parameters were conducted in order to establish the identity of the tested drugs.