Browsing by Author "Bakr, Riham O"

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Anaerobic biodegradation of anthracene by oral Firmicutes isolates from smokers and its potential pathway
(Elsevier Ltd., 2023-04) Wasfi, Reham; Moussa, Hams A; Bakr, Riham O; Abdeltawab, Nourtan F; Megahed, Salwa A
Exposure to polycyclic aromatic hydrocarbons (PAHs) from tobacco smoke has been linked to many negative health effects. Studies on the biodegradation of PAHs by human microbiota and detailed pathways for their anaerobic biodegradation are scarce despite their importance in getting rid of these toxic compounds. In a previous study for our group, we determined the ability of oral bacterial isolates in the anaerobic biodegradation of anthracene as a model of PAHs. Three isolates with the highest anthracene degradation ability were selected for the present study which include Limosilactobacillus fermentum, Veillonella parvula, and Streptococcus anginosus. In this study, we aimed at exploring and elucidating the anthracene anaerobic biodegradation pathways in selected Firmicutes oral isolates. Metabolites throughout the pathway were detected by gas chromatography coupled with mass spectroscopy (GC-MS) using anthracene as sole source of carbon. After incubation for 3 days, anthracene was undetected in the supernatant of L. fermentum and V. parvula, while a residual of 3% of anthracene was detected in presence of S. anginosus. Results revealed that anaerobic biodegradation by L. fermentum and V. parvula started with hydroxylation and dehydrogenation producing 9,10- anthraquinone and ended up with simpler structures such as catechol, while S. anginosus hydroxylation for anthracene resulted in the production of 1,2-anthracenediol and ended up with catechol and phthalic acid. The biodegradation of anthracene by oral bacteria could convert it to other toxic metabolites such as anthraquinone and catechol which were reported to have potential carcinogenic effects. Moreover, fatty acids detected as biodegradation metab- olites could be one of the causes of smokers’ heart-related diseases. Thus, this study explored oral metabolites resulting from smoking under anaerobic conditions towards elucidating the role of oral microbiota in health and disease states.
Antiviral potential of rosuvastatin and hesperidin in combination with favipiravir liposomal nanoformulations in targeting the main protease (M pro) of SARS-CoV-2: Molecular docking, molecular dynamics and in-vitro studies
(Editions de Sante, 2024-05) Elimam, Hanan; El-Sawy, Hossam S; Fayed, Marwa A.A; Mahmoud, Sara H; Bakr, Riham O; Saleh, Rasha M; Mostafa, Ahmed; Elshal, Mohamed F
Favipiravir (Fav) is a drug utilized to treat coronavirus disease 2019 (COVID-19) due its capacity to expedite the clearance of the SARS-CoV-2 virus through binding to its main protease (Mpro). However, the use of Fav has been associated with some adverse health effects. Meanwhile, numerous studies have highlighted the potential antiviral activities of specific phytochemicals and statins. Consequently, we thought to explore drug combination strategies involving certain statins and phytochemicals and their liposome nanoformulations either alone or with Fav, aiming to augment its efficacy and mitigate potential adverse effects. The molecular docking and molecular dynamic simulations analyses have revealed that hesperidin (HES) and rosuvastatin (ROS) have the best targeting potential for Mpro protein out of 10 phytochemicals and 6 statin compounds. The selected compounds were elaborated alone or with FAV into six nanoformulations FAV, ROS, HES, FAV/ROS, FAV/HES, and FAV/ ROS/HES-loaded liposomes. Light and electron microscope evaluations confirmed the vesicular shape of all liposomal dispersions. The entrapment capacity and release extent from FAV/ROS/HES-loaded liposomes was the lowest compared to other nanoformulations. In vitro, the FAV/HES or FAV/ROS-loaded liposomes displayed the highest capacity to impede the replication of SARS-CoV-2 with IC50 of 0.738 and 3.28 μg/mL, respectively. These results confirmed the potential of hesperidin and rosuvastatin as adjuvant medications with Favipiravir to combat COVID-19 and suggest the preference of the combinatory treatments. Finally, our findings provide a rational for further in-vivo studies to evaluate the potential activities of these drug combinations to mitigate the adverse events of favipiravir and to boost its SARS-CoV-2 clearance efficacy.
Chemical profling and cytotoxic potential of the n-butanol fraction of Tamarix nilotica fowers
(BioMed Central Ltd., 2023-05) Fayed, Marwa A. A; Bakr, Riham O; Yosri, Nermeen; Khalifa, Shaden A. M; El‑Seedi, Hesham R; Hamdan, Dalia I; Refaey, Mohamed S; El‑Seedi, Hesham R; Hamdan, Dalia I; Refaey, Mohamed S
Background Cancer represents one of the biggest healthcare issues confronting humans and one of the big chal‑ lenges for scientists in trials to dig into our nature for new remedies or to develop old ones with fewer side efects. Halophytes are widely distributed worldwide in areas of harsh conditions in dunes, and inland deserts, where, to cope with those conditions they synthesize important secondary metabolites highly valued in the medical feld. Several Tamarix species are halophytic including T.nilotica which is native to Egypt, with a long history in its tradition, found in its papyri and in folk medicine to treat various ailments. Methods LC–LTQ–MS–MS analysis and 1 H-NMR were used to identify the main phytoconstituents in the n- butanol fraction of T.nilotica fowers. The extract was tested in vitro for its cytotoxic efect against breast (MCF-7) and liver cell carcinoma (Huh-7) using SRB assay. Results T.nilotica n-butanol fraction of the fowers was found to be rich in phenolic content, where, LC–LTQ–MS– MS allowed the tentative identifcation of thirty-nine metabolites, based on the exact mass, the observed spectra fragmentation patterns, and the literature data, varying between tannins, phenolic acids, and favonoids. 1 H-NMR confrmed the classes tentatively identifed. The in-vitro evaluation of the n-butanol fraction showed lower activ‑ ity on MCF-7 cell lines with IC50>100 µg/mL, while the higher promising efect was against Huh-7 cell lines with an IC50= 37 µg/mL. Conclusion Our study suggested that T.nilotica fowers’n-butanol fraction is representing a promising cytotoxic can‑ didate against liver cell carcinoma having potential phytoconstituents with variable targets and signaling pathways.
Evaluation of the hepatoprotective activity of Pulicaria incisa subspecies candolleana and in silico screening of its isolated phenolics
(Elsevier, 01/12/2021) Bakr, Riham O; Shahat, Esraa A; Elissawy, Ahmed E; Fayez, Ahmed M; Eldahshan, Omayma A
Ethnopharmacological relevance Pulicaria incisa sub. candolleana E. Gamal-Eldin (Asteraceae) was traditionally used by Bedouins as a refreshing tea and as hypoglycemic, in gastrointestinal ailments, sinusitis and headache. Recently a great correlation has been established between liver cirrhosis and gastrointestinal dysfunction reflected by abdominal bloating, pain, diarrhea, constipation, besides decreased food intake. So far, the hepatoprotective effect of P. incisa sub. candolleana E. Gamal-Eldin was not studied before although other Pulicaria species have previously shown hepatoprotective and antioxidant effects. Aim of the study In this study, we aimed to identify the phytochemical constituents of the P. incisa sub. candolleana E. Gamal-Eldin hydroethanolic extract (PICE), as well as to evaluate the hepatoprotective, anti-inflammatory and antioxidant activities in methotrexate (MTX)- intoxicated rats. Besides, the molecular interaction between the isolated compounds and cyclooxygenase-2 (COX-2) and phospholipase 2 (PLA-2) were assessed by in-silico screening. Material and Methods The main phytoconstituents were characterized using liquid chromatography-tandem mass spectrometry (LC-MS-MS). Vacuum liquid chromatography (VLC) aided by preparative high-performance liquid chromatography (HPLC) were also used to isolate the major phenolics from the hydroethanolic extract. Their structures were elucidated using different spectroscopic analysis methods, including 1D and 2D nuclear magnetic resonance (NMR) and electrospray ionization mass spectrometry (ESI/MS). The hepatoprotective activity of three doses (100, 250, 500 mg/kg) of PICE in MTX-intoxicated rats was assessed and compared to silymarin as a standard. Additionally, in silico docking study on cyclooxygenase-2 (COX-2) and phospholipase 2 (PLA-2) was performed to justify the anti-inflammatory activity of the isolated compounds. Results Thirteen compounds were tentatively identified, including flavonoids and phenolic acids. Four main isolated compounds were identified as, eugenol-1-O-β-glucoside, 5-O-caffeoylquinic acid, 3, 5-di-O-caffeoylquinic acid and quercetin-3-O-β-glucoside. Treatment of MTX-intoxicated rats with the 250 mg/kg extract reversed the altered levels of biochemical markers of liver damage, ameliorated the oxidant status and reduced the inflammatory mediators, similar to treatment with silymarin. Quercetin-3-O-β-glucoside showed the best docking energy score of -19.12 kcal/mol against COX-2, forming four binding interactions with residues Leu 353, Arg 121, Tyr 356 and Ala 528, followed by 3,5-di-O-caffeoylquinic acid (-18.01 kcal/mol). Conclusion This study reveals P. incisa sub. candolleana as a rich source of phenolics including flavonoids, supporting its anti-inflammatory and hepatoprotective effects and suggesting its usage as a promising candidate in inflammatory conditions.
The metabolomic analysis of five Mentha species: cytotoxicity, anti-Helicobacter assessment, and the development of polymeric micelles for enhancing the anti-Helicobacter activity
(Royal Society of chemistry, 1/13/2021) Bakr, Riham O; Tawfike, Ahmed; El-Gizawy, Heba A; Tawfik, Nashwa; Abdelmohsen, Usama Ramadan; Abdelwahab, Miada F.; Alshareef, Walaa A; Fayez, Sahar M.; El-Mancy, Shereen M. S; El-Fishawy, Ahlam M; Abdelkawy, Mostafa A; Fayed, Marwa A. A
Mentha species are medicinally used worldwide and remain attractive for research due to the diversity of their phytoconstituents and large therapeutic indices for various ailments. This study used the metabolomics examination of five Mentha species (M. suaveolens, M. sylvestris, M. piperita, M. longifolia, and M. viridis) to justify their cytotoxicity and their anti-Helicobacter effects. The activities of species were correlated with their phytochemical profiles by orthogonal partial least square discriminant analysis (OPLS-DA). Tentatively characterized phytoconstituents using liquid chromatography high-resolution electrospray ionization mass spectrometry (LC-HR-ESI-MS) included 49 compounds: 14 flavonoids, 10 caffeic acid esters, 7 phenolic acids, and other constituents. M. piperita showed the highest cytotoxicity to HepG2 (human hepatoma), MCF-7 (human breast adenocarcinoma), and CACO2 (human colon adenocarcinoma) cells using 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assays. OPLS-DA and dereplication studies predicted that the cytotoxic activity was related to benzyl glucopyranoside-sulfate, a lignin glycoside. Furthermore, M. viridis was effective in suppressing the growth of Helicobacter pylori at a concentration of 50 mg mL1. OPLS-DA predicted that this activity was related to a dihydroxytrimethoxyflavone. M. viridis extract was formulated with Pluronic® F127 to develop polymeric micelles as a nanocarrier that enhanced the anti-Helicobacter activity of the extract and provided minimum inhibitory concentrations and minimum bactericidal concentrations of 6.5 and 50 mg mL1, respectively. This activity was also correlated to tentatively identified constituents, including rosmarinic acid, catechins, carvone, and piperitone oxide.
Sterols from Centaurea pumilio L. with cell proliferative activity: In vitro and in silico studies
(2023-04) Fayed, Marwa A. A; Al-Wahaibi, Lamya H; Bakr, Riham O; Nour, Mai S; Basudan, Omer A; Parvez, Mohammad K; Al-Dosari, Mohammed S; Abdel-Mageed, Wael M
Numerous studies highlighted the impact of natural products, particularly phytosterols, in wound healing while providing less expensive alternatives to che- mically synthesized drugs, with less side effects. Centaurea pumilio L. (family Asteraceae) is a rare and endangered species of genus Centaurea with few reports concerning its chemistry. Our phytochemical investigation for the non-polar fraction of its aerial parts led to the isolation and identification of the new compound (6) identified as stigmast-1,5-dien-3-O-β-D-glucopyranoside along with five known sterols and triterpenes (1–5) identified as taraxas- terol, β-sitosterol, stigmasterol, β-sitosterol glucoside, and stigmasterol-3-O-β-D-glucopyranoside. Structures of the isolated compounds have been characterized using 1D, 2D NMR, and mass spectral analyses. The cell viability and proliferative activity of the isolated compounds were evaluated using an MTT assay on cultured human primary umbilical vein endothelial cells (HUVEC). None of the com- pounds exhibited any sign of cytotoxicity. Nonetheless, com- pounds 5 and 6 moderately enhanced the HUVEC cell growth by 14 and 16%, respectively, at the maximal tested dose (50 µg/mL). As inhibition of glycogen synthase kinase 3-β (GSK3-β) enzyme is important to enhance the wound healing process; therefore, molecular docking was per- formed to understand the possible interactions between bioactive compounds 5 and 6 and GSK-3β binding pocket active amino acid residues. Both compounds were able to bind to the substrate‑binding site of GSK-3β and poten- tially interact with the key active site residues, forming strong π and hydrogen interactions with the catalytic site residues, revealing lower binding energy (−7.185 and −6.303 kcal/mol, respectively) than that of indirubin-3- monooxime (−5.303 kcal/mol); thereby representing strong natural replacements candidates for GSK-3β inhibitors