Browsing by Author "Bakr, Riham O."

Now showing 1 - 4 of 4

Antimicrobial activity of Vitex agnus-castus Essential Oil and Molecular Docking Study of Its Major Constituents
(Taylor & Francis, 2/26/2020) Bakr, Riham O.; Fayed, Marwa A.A.; Wasfi, Reham; Sonousi, Amr; Hassan, Rasha A.; Zaghloul, Soumaya S.
Antimicrobial resistance represents a public health problem worldwide that is associated with high morbidity and mortality which rose up the need for natural products as being an effective alternative. This study aims to evaluate the antimicrobial activity of the Vitex agnus-cactus L. essential oil (EO) towards bacterial and fungal strains of economic importance, besides, correlating its chemical constituents to the observed antimicrobial and antifungal activity using molecular docking. The chemical composition of essential oil was analyzed by gas chromatography-mass spectroscopy (GC-MS), where oxygenated monoterpenes (44.98 %) and monoterpenes (32.2 %) represented the major classes. Molecular docking study was carried out for the major identified essential oil constituents against bacterial protein targets, where, sabinene, 1,8 cineole, and linalool (the major oil constituents) acted on multi targets and reflected the effective antibacterial activity. Additionally, caryophyllene and verticiol showed a high binding affinity to Candida’s Farnesyl pyrophosphate synthase, a critical enzyme responsible for cell membrane integrity. V. agnus-cactus L. oil demonstrated itself as a powerful anticandidal agent providing a possible candidate in the pharmaceutical formulations
New Adenosine Derivatives from Aizoon canariense L.: In Vitro Anticholinesterase, Antimicrobial, and Cytotoxic Evaluation of Its Extracts
(MDPI, 2/24/2021) Bakr, Riham O.; El-Behairy, Mohammed F; Elissawy, Ahmed; Elimam, Hanan; Fayed, Marwa A. A.
Aizoaceae is a large succulent family characterized by many psychoactive species. Aizoon canariense L., a wild neglected plant traditionally used in gastrointestinal ailments, has been the subject of a limited number of phytochemical and biological studies. Therefore, herein, we investigated the in vitro cytotoxic, antimicrobial, and anticholinesteraseactivity of the aerial parts of A. canariense L. and analyzed the phytochemical compositions of the lipoidal and alkaloidal fractions. Petroleum ether extract showed the presence of behenic and tricosylic acid, while an in-depth investigation of the alkaloidal fraction revealed the identification of new adenine based alkaloids (1–5), which were isolated and identified for the first time from Aizoon canariense L. Their structures were elucidated based on extensive spectroscopic analyses. The alkaloidal extract showed a powerful cytotoxic effect (IC50 14–28 μg/mL), with the best effect against colon carcinoma, followed by liver and breast carcinomas. The alkaloidal extract also had a potent effect against Candida albicans and Escherichia coli, with minimum inhibitory concentrations (MIC) values of 312.5 and 625 µg/mL. The in vitro anticholinesterase activity was potent, with IC50 < 200 ng/mL for the tested extracts compared with 27.29 ± 0.49 ng/mL for tacrine.
Pharmacophore based virtual screening for natural product database revealed possible inhibitors for SARS-COV-2 main protease
(Elsevier, 2022-05) El-Ashrey, Mohamed K; Bakr, Riham O.; Fayed, Marwa A.A; Refaey, Rana H; Nissan, Yassin M
The challenge continues globally triggered by the absence of an approved antiviral drug against COVID-19 virus infection necessitating global concerted efforts of scientists. Nature still provides a renewable source for drugs used to solve many health problems. The aim of this work is to provide new candidates from natural origin to overcome COVID-19 pandemic. A virtual screening of the natural compounds database (47,645 compounds) using structure-based pharmacophore model and molecular docking simulations reported eight hits from natural origin against SARS-CoV-2 main proteinase (Mpro) enzyme. The successful candidates were of terpenoidal nature including taxusabietane, Isoadenolin A & C, Xerophilusin B, Excisanin H, Macrocalin B and ponicidin, phytoconstituents isolated from family Lamiaceae and sharing a common ent-kaurane nucleus, were found to be the most successful candidates. This study suggested that the diterpene nucleus has a clear positive contribution which can represent a new opportunity in the development of SARS-CoV-2 main protease inhibitors
Phytochemical and Biological Investigation of Eugenia uniflora L. Cultivated in Egypt
(ACADEMIC JOURNALS, 2017) Bakr, Riham O.; Mohamed, Shaza A.; Waly, Nermien E
Eugenia uniflora L. (Myrtaceae) is a plant species used in folk medicine for treatment of various disorders. This study aims to quantify the phenolic and flavonoid contents of E. uniflora aqueous methanolic extract (AME), identification of its major constituents, as well as the evaluation of its biological activity. Quantification was performed using colorimetric assays. Column chromatographic separation was used for isolation of the major phenolic constituents while their structures were elucidated by 1D- and 2D Nuclear magnetic resonance spectroscopy (NMR) spectra. Alkaloids were identified using gas chromatography-mass spectrometry (GC-MS) analysis. The antidepressant activity of E. uniflora AME in mice was evaluated using the tail suspension test (TST). The weight control effect was evaluated by serial weighing. The results showed high phenolic and flavonoid contents of E. uniflora AME. The chromatographic investigation identified a new flavonoid, myricetin 3-O-(4'', 6''- digalloyl) glucopyranoside, for first time in this genus, along with four flavonoids and phenolic acids. Integerrimine alkaloid was identified through GC/MS analysis. Administration of E. uniflora AME significantly reduced the immobility time in mice (P value of < 0.0001) in a dose- dependent manner for doses of 1, 10, 50 and 100 mg/kg. Also, a non-significant weight reduction in mice chronically treated with the E. uniflora AME was observed. Our study reports the isolation of myricetin 3-O- (4'', 6''- digalloyl) glucopyranoside from E. uniflora. It confirms that E. uniflora leaf extract has an antidepressant and anti-obesity effect.