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South African Journal of Science, 2022
We analysed four different Sudanese roselle samples for their potential as novel xanthine oxidase... more We analysed four different Sudanese roselle samples for their potential as novel xanthine oxidase (XO) inhibitors. Phytochemical screening showed the presence of polyphenols, flavonoids, organic acids, saponins and sterols in all samples. Liquid chromatography with tandem mass spectrometry (LC-MS/ MS) was used to identify and characterise five anthocyanins in all samples: cyanidin-3-glucoside (cy-3-glu), delphinidin-3-sambubioside (dp-3-sam), cyanidin-3-rhamnoside (cy-3-rhm), delphinidin-3‑rhamnoside (dp-3-rhm) and pelargonidin-3-glucoside (pg-3-glu). Identification of cy-3-rhm, dp-3-rhm and pg-3-glu confirmed the selectivity and sensitivity of LC-MS as a powerful technique for identifying anthocyanins. In silico studies of the identified anthocyanins were performed to explore their promising inhibitory activity toward XO. Interactions between the ligand and the enzyme were via the H-bond, and hydrophobic (π-alkyl, π-sigma and alkyl) and/or electrostatic (π-cation) bonds. Inhibition...
This study aims to identify anthocyanin pigments in Sudanese roselle and examine their inhibitory... more This study aims to identify anthocyanin pigments in Sudanese roselle and examine their inhibitory activity toward xanthine oxidase (XO) enzyme via in silico docking approach. A number of four samples of Sudanese roselle (red and white) from different regions of Sudan were investigated by high sensitive technique, i.e. LC-MS to identify anthocyanins. Four anthocyanins were identified in all samples; delphinidin-3-glucoside (Dp-3-glu), cyanidin-3-sambubioside (Cy-3-sam), pelargonidin chloride (Pg Chloride), and petuinidin-3-glucoside (Pt-3-glu); in addition to one flavanol; gossypetin (Goss). The anthocyanins of the white samples are suggested to be presented in the yellowish or colorless pseudo base structures. The identified anthocyanins were tested against the inhibition toward xanthine oxidase via molecular docking. All anthocyanins were found to be excellent XO inhibitors superior to the most recent commercially used hyperuricemia drug; i.e. topiroxostat. The binding energies of ...
Surface Science, 2013
ABSTRACT With the ultimate purpose of studying the properties of potassium clusters deposited on ... more ABSTRACT With the ultimate purpose of studying the properties of potassium clusters deposited on a surface, we have at first studied the energetic and structural properties of isolated potassium clusters with up to 20 atoms. The global total-energy-minima structures have been determined by using the Density Functional Tight Binding method (DFTB) combined with genetic algorithms. For the isolated clusters in the gas phase we analyze the binding energy as well as the stability function. Moreover, structural similarity is studied using so-called similarity functions. Also the overall shape of the clusters and the radial distribution of the atoms are studied. Subsequently, we study the changes in the structure when these clusters are deposited on one out of two different potassium surfaces. Finally, the energy related to the deposition is studied in detail.
South African Journal of Science, 2022
We analysed four different Sudanese roselle samples for their potential as novel xanthine oxidase... more We analysed four different Sudanese roselle samples for their potential as novel xanthine oxidase (XO) inhibitors. Phytochemical screening showed the presence of polyphenols, flavonoids, organic acids, saponins and sterols in all samples. Liquid chromatography with tandem mass spectrometry (LC-MS/ MS) was used to identify and characterise five anthocyanins in all samples: cyanidin-3-glucoside (cy-3-glu), delphinidin-3-sambubioside (dp-3-sam), cyanidin-3-rhamnoside (cy-3-rhm), delphinidin-3‑rhamnoside (dp-3-rhm) and pelargonidin-3-glucoside (pg-3-glu). Identification of cy-3-rhm, dp-3-rhm and pg-3-glu confirmed the selectivity and sensitivity of LC-MS as a powerful technique for identifying anthocyanins. In silico studies of the identified anthocyanins were performed to explore their promising inhibitory activity toward XO. Interactions between the ligand and the enzyme were via the H-bond, and hydrophobic (π-alkyl, π-sigma and alkyl) and/or electrostatic (π-cation) bonds. Inhibition...
This study aims to identify anthocyanin pigments in Sudanese roselle and examine their inhibitory... more This study aims to identify anthocyanin pigments in Sudanese roselle and examine their inhibitory activity toward xanthine oxidase (XO) enzyme via in silico docking approach. A number of four samples of Sudanese roselle (red and white) from different regions of Sudan were investigated by high sensitive technique, i.e. LC-MS to identify anthocyanins. Four anthocyanins were identified in all samples; delphinidin-3-glucoside (Dp-3-glu), cyanidin-3-sambubioside (Cy-3-sam), pelargonidin chloride (Pg Chloride), and petuinidin-3-glucoside (Pt-3-glu); in addition to one flavanol; gossypetin (Goss). The anthocyanins of the white samples are suggested to be presented in the yellowish or colorless pseudo base structures. The identified anthocyanins were tested against the inhibition toward xanthine oxidase via molecular docking. All anthocyanins were found to be excellent XO inhibitors superior to the most recent commercially used hyperuricemia drug; i.e. topiroxostat. The binding energies of ...
Surface Science, 2013
ABSTRACT With the ultimate purpose of studying the properties of potassium clusters deposited on ... more ABSTRACT With the ultimate purpose of studying the properties of potassium clusters deposited on a surface, we have at first studied the energetic and structural properties of isolated potassium clusters with up to 20 atoms. The global total-energy-minima structures have been determined by using the Density Functional Tight Binding method (DFTB) combined with genetic algorithms. For the isolated clusters in the gas phase we analyze the binding energy as well as the stability function. Moreover, structural similarity is studied using so-called similarity functions. Also the overall shape of the clusters and the radial distribution of the atoms are studied. Subsequently, we study the changes in the structure when these clusters are deposited on one out of two different potassium surfaces. Finally, the energy related to the deposition is studied in detail.