UDOM IR :: Browsing by Author "Sahini, Mtabazi G."

Browsing by Author "Sahini, Mtabazi G."

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Abrogating the nsp10–nsp16 switching mechanisms in SARS-CoV-2 by phytochemicals from Withania somnifera: a molecular dynamics study
(Taylor & Francis, 2021) Vuai, Said A. H.; Onokaa, Isaac; Sahini, Mtabazi G.; Swai, Hulda S.; Shadrack, Daniel M.
The search for therapeutic small molecules and vaccines for Covid-19 treatment is an urgent but evolving topic. The virus has claimed over 3,782,490 lives (as of 12 June 2021), with the figure expected to rise due to the high versatility of the SAR-CoV-2 variant. Therapeutic options based on SARS-CoV-2 inhibitor are essential. Withanolides have a long history in traditional medicines with versatile biological properties including antiviral activities. In this study, the inhibitory potential of withanolides from Withania somnifera (Ashwagandha) against SARS-CoV-2 non-structural protein 10 (nsp10) was investigated by employing atomistic in silico methods viz molecular docking, molecular dynamics and binding free energy calculations. Investigated Withania somnifera compounds demonstrated binding affinity to the nsp10 and in its complex form, that is, nsp10-nsp16 heterodimer. Two withanolides; withanoside IV and withanoside V isolated from the roots of Withania somnifera demonstrated strong inhibition with binding free energies of −29.5 and −29.1 kJ/mol, respectively. Molecular dynamics and binding free energy ascertained the stability of withanoside IV. Water molecules, although known to play an important role in mediating biological systems, herein, water was found to have a repulsive binding effect to some residues, suggesting that the binding of withanoside IV would require dewetting of the nsp10 or displacing the water to bulk solvents. Interestingly, residues in the nsp10 that are responsible for forming stable interaction at the nsp10–nsp16 were found to be strongly interacting with withanoside IV, hence weakening the nsp10–nsp16 interaction and recognition. Further in vitro and in vivo experiments are recommended to validate the anti-SARS-COV-2 potential of these phytochemicals.
Abrogating the nsp10–nsp16 switching mechanisms in SARS-CoV-2 by phytochemicals from Withania somnifera: a molecular dynamics study
(Taylor & Francis, 2021) Vuai, Said A. H.; Onoka, Isaac; Sahini, Mtabazi G.; Swai, Hulda S.; Shadrack, Daniel M.
The search for therapeutic small molecules and vaccines for Covid-19 treatment is an urgent but evolving topic. The virus has claimed over 3,782,490 lives (as of 12 June 2021), with the figure expected to rise due to the high versatility of the SAR-CoV-2 variant. Therapeutic options based on SARS-CoV-2 inhibitor are essential. Withanolides have a long history in traditional medicines with versatile biological properties including antiviral activities. In this study, the inhibitory potential of withanolides from Withania somnifera (Ashwagandha) against SARS-CoV-2 non-structural protein 10 (nsp10) was investigated by employing atomistic in silico methods viz molecular docking, molecular dynamics and binding free energy calculations. Investigated Withania somnifera compounds demonstrated binding affinity to the nsp10 and in its complex form, that is, nsp10-nsp16 heterodimer. Two withanolides; withanoside IV and withanoside V isolated from the roots of Withania somnifera demonstrated strong inhibition with binding free energies of −29.5 and −29.1 kJ/mol, respectively. Molecular dynamics and binding free energy ascertained the stability of withanoside IV. Water molecules, although known to play an important role in mediating biological systems, herein, water was found to have a repulsive binding effect to some residues, suggesting that the binding of withanoside IV would require dewetting of the nsp10 or displacing the water to bulk solvents. Interestingly, residues in the nsp10 that are responsible for forming stable interaction at the nsp10–nsp16 were found to be strongly interacting with withanoside IV, hence weakening the nsp10–nsp16 interaction and recognition. Further in vitro and in vivo experiments are recommended to validate the anti-SARS-COV-2 potential of these phytochemicals.
Approaches to mitigation of hydrogen sulfide during anaerobic digestion process – A review
(Heliyon, 2023) Mutegoa, Eric; Sahini, Mtabazi G.
Anaerobic digestion (AD) is the primary technology for energy production from wet biomass under a limited oxygen supply. Various wastes rich in organic content have been renowned for enhancing the process of biogas production. However, several other intermediate unwanted products such as hydrogen sulfide, ammonia, carbon dioxide, siloxanes and halogens have been generated during the process, which tends to lower the quality and quantity of the harvested biogas. The removal of hydrogen sulfide from wastewater, a potential substrate for anaerobic digestion, using various technologies is covered in this study. It is recommended that microaeration would increase the higher removal efficiency of hydrogen sulfide based on a number of benefits for the specific method. The process is primarily accomplished by dosing smaller amounts of oxygen in the digester, which increases the system's oxidizing capacity by rendering the sulfate reducing bacteria responsible for converting sulfate ions to hydrogen sulfide inactive. This paper reviews physicochemical and biological methods that have been in place to eliminate the effects of hydrogen sulfide from wastewater treated anaerobically and future direction to remove hydrogen sulfide from biogas produced.
Approaches to mitigation of hydrogen sulfide during anaerobic digestion process – A review
(Elsevier BV, 2023) Mutegoa, Eric; Sahini, Mtabazi G.
Anaerobic digestion (AD) is the primary technology for energy production from wet biomass under a limited oxygen supply. Various wastes rich in organic content have been renowned for enhancing the process of biogas production. However, several other intermediate unwanted products such as hydrogen sulfide, ammonia, carbon dioxide, siloxanes and halogens have been generated during the process, which tends to lower the quality and quantity of the harvested biogas. The removal of hydrogen sulfide from wastewater, a potential substrate for anaerobic digestion, using various technologies is covered in this study. It is recommended that microaeration would increase the higher removal efficiency of hydrogen sulfide based on a number of benefits for the specific method. The process is primarily accomplished by dosing smaller amounts of oxygen in the digester, which increases the system's oxidizing capacity by rendering the sulfate reducing bacteria responsible for converting sulfate ions to hydrogen sulfide inactive. This paper reviews physicochemical and biological methods that have been in place to eliminate the effects of hydrogen sulfide from wastewater treated anaerobically and future direction to remove hydrogen sulfide from biogas produced.
Cation inter-diffusion and formation of intermediate phases in CoO and La2NiO4+δ diffusion couples
(Elsevier, 2022) Sahini, Mtabazi G.; Wiik, Kjell; Grande, Tor
Cation interdiffusion between La2NiO4+δ (LN) and CoO diffusion couples was investigated by thermal annealing in ambient air at 1200 °C for 48 and 168 h, and analysis of the cross sections by scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS). Co diffusion into the LN layer was significant, while Ni diffusion into the CoO layer was minor. Formation of LaCoO3, LaCo0.5Ni0.5O3, and La3(Ni0.8Co0.2)2O7 were observed in the LN layer at increasing distance from the boundary.
Cation–π interactions drive hydrophobic self-assembly and aggregation of niclosamide in water †
(The Royal Society of Chemistry, 2021) Vuai, Said A. H.; Sahini, Mtabazi G.; Onoka, Isaac; Kiruri, Lucy W.; Shadrack, Daniel M.
The beneficial medicinal effects of niclosamide have been reported to be hampered by poor aqueous solubility and so a higher concentration dosage is required. In this work, we have studied the aggregation properties of niclosamide in water by varying the number of monomers. We have employed all-atom classical molecular dynamics simulation in order to explore such properties. The equilibrium structure exists in an aggregated state with structural rearrangements of the stacking units. Niclosamide monomers tend to form clusters in an orderly manner and tend to aggregate in parallel and antiparallel orientations of the phenyl rings as the monomers are increased in number from 4 to 9. Upon increasing the size from 9 to 14, and from 49 to 150, a considerable dominance of the metastable parallel arrangement is observed, resulting in the formation of a closely packed cluster with hydrophobic contacts. The metastable conformation self-arranges to a T-shape before forming a stable planar antiparallel displaced conformation. The aggregated π–π parallel and cation–π antiparallel clusters in water exist in a β-conformer. We further observed that formation of a stable cluster aggregate entails the formation of an intermediate metastable cluster that disperses in solution forming a large stable cluster. We also discovered that movement of the water is faster in less aggregated clusters and as the cluster size increases, the mobility rate becomes much slower.
Ethnomedicinal uses, phytochemistry and pharmacological study of Ocimum americanum L.: A review
(Elsevier, 2023) Luanda, Amos; Ripanda, Asha; Sahini, Mtabazi G.; Makangara, John J.
Background: Ocimum americanum L., commonly known as Hoary basil, is a wild aromatic shrub traditionally used to treat different ailments. Its leaves, flowers and aerial parts have been widely studied to evaluate its medicinal potential such as lowering blood pressure, treatment of microbial infections, malaria, cold, liver and eye problems. Purpose: This study aims to provide an in-depth review of ethnomedicinal uses, phytochemistry, and pharmacological activities of O. americanum, to evaluate its benefits, challenges and potential future prospects. Methods: All the information about O. americanum was collected from various platforms, including google scholar, PubMed, ScienceDirect, plants of the world online and Research4Life. The acceptance criteria of the collected information based on the PICOS model. The GRADE approach was used to analyze and evaluate the quality of the collected information. Results: This study showed that O. americanum has tremendous therapeutic potential to be integrated into mainstream medical practice to manage various medical conditions. The inconsistence of the phytoconstituents among the plant parts resulted in a significant variation of pharmacological activities. Plant originality, genetic variability and extraction techniques are among the factors contributing to the variation of phytoconstituents that are responsible for pharmacological activities. Conclusion: This study revealed that O. americanum is a potential medicinal plant for mitigating various medical conditions. However, future study should continue to focus on the bioactive compounds and their mechanisms of action. Additionally, the utilization of the O. americanum for the development of drugs as well as quality evaluation in clinical settings are highly recommended.
Polylactic acid (PLA)-based materials: a review on the synthesis and drug delivery applications
(Springer Science and Business Media LLC, 2023) Sahini, Mtabazi G.
Controlled drug release is an important aspect of biomedical applications of polymer materials. Polylactic acid (PLA)-based materials have been thoroughly researched for biomedical applications, owing to their attractive properties. Here, the advancements in the preparation and application of PLA-based polymers for drug delivery are reviewed. In addition to discussing the potentials of the PLA-based materials for drug delivery, the production techniques and various geometries of the drug carriers are also covered. The review has established that several drugs, including ibuprofen, amphotericin B, paclitaxel, 5-fluorouracil, doxorubicin, ketoprofen, rifampicin, salinomycin, ciprofloxacin, and ornidazole, have been successfully loaded into and released from PLA-based materials. Due to the hydrophobic nature of PLA, its modification to accommodate both the hydrophobic and hydrophilic drugs is emphasized in the literature.
Polylactic acid (PLA)-based materials: a review on the synthesis and drug delivery applications
(Springer Science and Business Media LLC, 2023) Sahini, Mtabazi G.
Controlled drug release is an important aspect of biomedical applications of polymer materials. Polylactic acid (PLA)-based materials have been thoroughly researched for biomedical applications, owing to their attractive properties. Here, the advancements in the preparation and application of PLA-based polymers for drug delivery are reviewed. In addition to discussing the potentials of the PLA-based materials for drug delivery, the production techniques and various geometries of the drug carriers are also covered. The review has established that several drugs, including ibuprofen, amphotericin B, paclitaxel, 5-fluorouracil, doxorubicin, ketoprofen, rifampicin, salinomycin, ciprofloxacin, and ornidazole, have been successfully loaded into and released from PLA-based materials. Due to the hydrophobic nature of PLA, its modification to accommodate both the hydrophobic and hydrophilic drugs is emphasized in the literature.
Relaxed complex scheme and molecular dynamics simulation suggests small molecule inhibitor of human TMPRSS2 for combating COVID-19
(Taylor & Francis, 2021) Vuai, Said A. H.; Ogedjo, Marcelina M.; Isaac, Onoka; Sahini, Mtabazi G.; Swai, Hulda S.; Shadrack, Daniel M.
As the coronavirus disease 19 (COVID-19) pandemic continues to pose a health and economic crisis worldwide, the quest for drugs and/or vaccines against the virus continues. The human transmembrane protease serine 2 (TMPRSS2) has attracted attention as a target for drug discovery, as inhibition of its catalytic reaction would result in the inactivation of the proteolytic cleavage of the SARS-CoV-2 S protein. As a result, the inactivation prevents viral cell entry to the host’s cell. In this work, we screened and identified two potent molecules that interact and inhibit the catalytic reaction by using computational approaches. Two docking screening experiments were performed utilizing the crystal structure and holo ensemble structure obtained from molecular dynamics in bound form. There is enhancement and sensitivity of docking results to the holo ensemble as compared to the crystal structure. Compound 1 demonstrated a similar inhibition value to nafamostat by interacting with catalytic triad residues His296 and Ser441, thereby disrupting the already established hydrogen bond interaction. The stability of the ligand–TMPRSS2 complexes was studied by molecular dynamics simulation, and the binding energy was re-scored by using molecular mechanics Poisson-Boltzmann surface area (MM-PBSA) binding free energy. The obtained compounds may serve as an initial point toward the discovery of potent TMPRSS2 inhibitors upon further in vivo validation.
Superparamagnetic iron oxide nanoparticles for drug delivery applications
(Elsevier, 2023) Sahini, Mtabazi G.; Banyikwa, Andrew T.
Because of their demonstrated biomedical application potentials, functional nanoparticles have been extensively studied. Among these, superparamagnetic iron oxide nanoparticles (SPIONs) have received a significant attention for diagnostic and therapeutic purposes. This chapter discusses the latest developments in the drug delivery applications of SPIONs. The concept of drug delivery and targeted drug delivery is introduced first. The properties of iron oxide, particularly magnetic properties, are presented in order for the reader to gain insight into the origins of superparamagnetism. The chapter also discusses common methods of synthesis and surface functionalization of SPIONs, as well as approaches for loading and release of drug, and some clinically approved SPIONs-based drugs. Despite the associated challenges, the therapeutic and diagnostic use of SPIONs is a promising technology that should be pursued further
Theoretical and conceptual framework to design D-π-A type organic dyes for application dye-sensitized solar cells
(Elsevier BV, 2024) Makangara, John J.; Sahini, Mtabazi G.; Babu, Numbury Surendra
The optimized structures and absorption spectra of five D-A-type organic dyes (M1, M2, M3, M4, and M5) were investigated using Density Functional Theory (DFT) and Time-Dependent Density Functional Theory (TD-DFT). These dyes contain the same electron acceptors and -spacers but distinct 3,6- and 2,7-carbazole electron-donating groups. The results showed coplanar geometries for the dyes, which implied strong conjugation. When intramolecular charge transfer was investigated, it was discovered that 3,6-carbazole had a better capacity to give electrons than 2,7-carbazole. These dyes' projected orbital energy levels indicate that excited dyes might successfully decrease by electrolyte while oxidized dyes could successfully inject electrons into semiconductor conduction bands. The study investigated the suitability of different dyes for use in dye-sensitized solar cells (DSSCs) and found that the M2 dye, which contains a thio group as the terminal electron donor, exhibited the most promising optoelectronic properties. In particular, M2 had a narrow energy gap, superior optical qualities, optimal FMO energy levels, the lowest total value, and greater GInject and GReg values compared to the other dyes tested. These factors contributed to M2's superior photosensitizing performance, suggesting that using M2 in DSSCs may lead to higher optoelectronic characteristics and total energy conversion efficiency compared to using other dyes.
Theoretical and conceptual framework to design D-π-A type organic dyes for application dye-sensitized solar cells
(Elsevier BV, 2024) Makangara, John J.; Sahini, Mtabazi G.; babu, Numbury Surendra
The optimized structures and absorption spectra of five D-A-type organic dyes (M1, M2, M3, M4, and M5) were investigated using Density Functional Theory (DFT) and Time-Dependent Density Functional Theory (TD-DFT). These dyes contain the same electron acceptors and -spacers but distinct 3,6- and 2,7-carbazole electron-donating groups. The results showed coplanar geometries for the dyes, which implied strong conjugation. When intramolecular charge transfer was investigated, it was discovered that 3,6-carbazole had a better capacity to give electrons than 2,7-carbazole. These dyes' projected orbital energy levels indicate that excited dyes might successfully decrease by electrolyte while oxidized dyes could successfully inject electrons into semiconductor conduction bands. The study investigated the suitability of different dyes for use in dye-sensitized solar cells (DSSCs) and found that the M2 dye, which contains a thio group as the terminal electron donor, exhibited the most promising optoelectronic properties. In particular, M2 had a narrow energy gap, superior optical qualities, optimal FMO energy levels, the lowest total value, and greater GInject and GReg values compared to the other dyes tested. These factors contributed to M2's superior photosensitizing performance, suggesting that using M2 in DSSCs may lead to higher optoelectronic characteristics and total energy conversion efficiency compared to using other dyes.
Towards attaining SDG 6: The opportunities available for capacitive deionization technology to provide clean water to the African population
(Elsevier, 2022) Sufiani, Omari; Sahini, Mtabazi G.; Elisadiki, Joyce
The unavailability of clean water caused by population growth, increased industrial activities, and global climate change is a major challenge in many communities. A number of desalination technologies including distillation, reverse osmosis and electrodialysis, have been used to supplement the available water resources. However, these technologies are energy intensive and demand a significant financial commitment. Capacitive deionization (CDI) is an emerging desalination technology which is promising to provide water at a reasonable cost, especially in societies with limited incomes such as those in Africa. The opportunities for CDI to provide clean water to the African population are discussed in this paper. These opportunities include electrosorption at low potential, low energy consumption, large quantities of agricultural wastes for the production of electrode materials, high sunshine irradiation throughout the year, suitability for disinfection and defluoridation and its applications in the removal of heavy metals and emerging pollutants. Due to the existence of numerous enabling conditions, the analysis from this paper demonstrates that CDI can be a dependable method to provide clean water in Africa.

Browsing by Author "Sahini, Mtabazi G."

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