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Your search keyword '"Ahmed R. Hamed"' showing total 4 results
Start Over Author "Ahmed R. Hamed" Publisher mdpi ag
4 results on '"Ahmed R. Hamed"'

1. Euphosantianane A–D: Antiproliferative Premyrsinane Diterpenoids from the Endemic Egyptian Plant Euphorbia Sanctae-Catharinae

Author

Mohamed-Elamir F. Hegazy, Ahmed R. Hamed, Mahmoud A. A. Ibrahim, Zienab Talat, Eman H. Reda, Nahla S. Abdel-Azim, Faiza M. Hammouda, Seikou Nakamura, Hisashi Matsuda, Eman G. Haggag, Paul W. Paré, and Thomas Efferth

Subjects
Euphorbia sanctae-catharinae, Euphorbiaceae, diterpenes, flavonoids, TDDTF-ECD, tumor anti-proliferative activity, Organic chemistry, QD241-441
Abstract

Euphorbia species are rich in diterpenes. A solvent extraction of Euphorbia sanctae-catharinae, a species indigenous to the Southern Sinai of Egypt, afforded several premyrsinane diterpenoids (1–4) as well as previously reported metabolites (5–13) that included three flavonoids. Isolated compounds were chemically characterized by spectroscopic analysis. Identified compounds were bioassayed for anti-proliferative activity in vitro against colon (Caco-2) and lung (A549) tumor cell lines. Compound 9 exhibited robust anti-proliferative activity against A549 cells (IC50 = 3.3 µM). Absolute configurations for 8 versus 9 were determined by experimental and TDDFT-calculated electronic circular dichorism (ECD) spectra.

Published
2018
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2. Cembrene Diterpenoids with Ether Linkages from Sarcophyton ehrenbergi: An Anti-Proliferation and Molecular-Docking Assessment

Author

Mohamed-Elamir F. Hegazy, Abdelsamed I. Elshamy, Tarik A. Mohamed, Ahmed R. Hamed, Mahmoud A. A. Ibrahim, Shinji Ohta, and Paul W. Paré

Subjects
Sarcophyton ehrenbergi, soft coral, terpenes, cembranoids, cytotoxic activity, molecular docking, Biology (General), QH301-705.5
Abstract

Three new cembrene diterpenoids, sarcoehrenbergilid A–C (1–3), along with four known diterpenoids, sarcophine (4), (+)-7α,8β-dihydroxydeepoxysarcophine (5), sinulolide A (6), and sinulolide B (7), and one steroid, sardisterol (8), were isolated and characterized from a solvent extract of the Red Sea soft coral Sarcophyton ehrenbergi. Chemical structures were elucidated by NMR and MS analyses with absolute stereochemistry determined by X-ray analysis. Since these isolated cembrene diterpenes contained 10 or more carbons in a large flexible ring, conformer stabilities were examined based on density functional theory calculations. Anti-proliferative activities for 1–8 were evaluated against three human tumor cell lines of different origins including the: lung (A549), colon (Caco-2), and liver (HepG2). Sardisterol (8) was the most potent of the metabolites isolated with an IC50 of 27.3 µM against the A549 cell line. Since an elevated human-cancer occurrence is associated with an aberrant receptor function for the epidermal growth factor receptor (EGFR), molecular docking studies were used to examine preferential metabolite interactions/binding and probe the mode-of-action for metabolite-anti tumor activity.

Published
2017
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3. Euphosantianane A–D: Antiproliferative Premyrsinane Diterpenoids from the Endemic Egyptian Plant Euphorbia Sanctae-Catharinae

Author

Thomas Efferth, Eman G. Haggag, Hisashi Matsuda, Paul W. Paré, Faiza Hammouda, Mahmoud A. A. Ibrahim, Ahmed R. Hamed, Seikou Nakamura, Eman H. Reda, Mohamed-Elamir F. Hegazy, Nahla S. Abdel-Azim, and Zienab Talat

Subjects
Pharmaceutical Science, Tumor cells, 01 natural sciences, Analytical Chemistry, TDDTF-ECD, lcsh:QD241-441, tumor anti-proliferative activity, lcsh:Organic chemistry, Drug Discovery, Physical and Theoretical Chemistry, Solvent extraction, A549 cell, Euphorbia, biology, Traditional medicine, 010405 organic chemistry, Chemistry, Organic Chemistry, Euphorbiaceae, diterpenes, Euphorbia sanctae-catharinae, biology.organism_classification, 0104 chemical sciences, 010404 medicinal & biomolecular chemistry, Chemistry (miscellaneous), flavonoids, Molecular Medicine
Abstract

Euphorbia species are rich in diterpenes. A solvent extraction of Euphorbia sanctae-catharinae, a species indigenous to the Southern Sinai of Egypt, afforded several premyrsinane diterpenoids (1&ndash, 4) as well as previously reported metabolites (5&ndash, 13) that included three flavonoids. Isolated compounds were chemically characterized by spectroscopic analysis. Identified compounds were bioassayed for anti-proliferative activity in vitro against colon (Caco-2) and lung (A549) tumor cell lines. Compound 9 exhibited robust anti-proliferative activity against A549 cells (IC50 = 3.3 &micro, M). Absolute configurations for 8 versus 9 were determined by experimental and TDDFT-calculated electronic circular dichorism (ECD) spectra.

Published
2018

4. Curcumin-Loaded Solid Lipid Nanoparticles Bypass P-Glycoprotein Mediated Doxorubicin Resistance in Triple Negative Breast Cancer Cells

Author

Carlo Zuddas, Barbara Rolando, Ahmed R. Hamed, Sohair R. Fahmy, Marina Gallarate, Daniela Chirio, Dimas Carolina Belisario, Chiara Riganti, Simona Sapino, Abdel-Hamid Zaki Abdel-Hamid, Elena Peira, Joanna Kopecka, Gamal-Eldein Fathy Abd-Ellatef, Elena Gazzano, and Mohamed-Assem S. Marie

Subjects
Curcumin, Combination therapy, Doxorubicin resistance, P-glycoprotein, Solid lipid nanoparticles, Triple negative breast cancer, lcsh:RS1-441, Pharmaceutical Science, Article, lcsh:Pharmacy and materia medica, 03 medical and health sciences, chemistry.chemical_compound, 0302 clinical medicine, Solid lipid nanoparticle, medicine, Doxorubicin, Triple-negative breast cancer, 030304 developmental biology, 0303 health sciences, biology, Chemistry, Multiple drug resistance, 030220 oncology & carcinogenesis, Toxicity, Cancer research, biology.protein, medicine.drug
Abstract

Multidrug resistance (MDR) is a critical hindrance to the success of cancer chemotherapy. The main thing responsible for MDR phenotypes are plasma-membranes associated with adenosine triphosphate (ATP) Binding Cassette (ABC) drug efflux transporters, such as the P-glycoprotein (Pgp) transporter that has the broadest spectrum of substrates. Curcumin (CURC) is a Pgp inhibitor, but it is poorly soluble and bioavailable. To overcome these limitations, we validated the efficacy and safety of CURC, loaded in biocompatible solid lipid nanoparticles (SLNs), with or without chitosan coating, with the goal of increasing the stability, homogeneous water dispersibility, and cellular uptake. Both CURC-loaded SLNs were 5&ndash, 10-fold more effective than free CURC in increasing the intracellular retention and toxicity of doxorubicin in Pgp-expressing triple negative breast cancer (TNBC). The effect was due to the decrease of intracellular reactive oxygen species, consequent inhibition of the Akt/IKK&alpha, &beta, /NF-kB axis, and reduced transcriptional activation of the Pgp promoter by p65/p50 NF-kB. CURC-loaded SLNs also effectively rescued the sensitivity to doxorubicin against drug-resistant TNBC tumors, without signs of systemic toxicity. These results suggest that the combination therapy, based on CURC-loaded SLNs and doxorubicin, is an effective and safe approach to overcome the Pgp-mediated chemoresistance in TNBC.

Published
2020
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