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Samuel K. Kwofie
Department of Biomedical Engineering, School of Engineering Sciences, College of Basic and Applied Sciences, University of Ghana, Accra, Ghana

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Original article
Published: 05 August 2021 in Molecular Diversity
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Schistosomiasis is a neglected tropical disease caused by helminths of the Schistosoma genus. Despite its high morbidity and socio-economic burden, therapeutics are just a handful with praziquantel being the main drug. Praziquantel is an old drug registered for human use in 1982 and has since been administered en masse for chemotherapy, risking the development of resistance, thus the need for new drugs with different mechanisms of action. This review examines the use of machine learning (ML) in this era of big data to aid in the prediction of novel antischistosomal molecules. It first discusses the challenges of drug discovery in schistosomiasis. Explanations are then offered for big data, its characteristics and then, some open databases where large biochemical data on schistosomiasis can be obtained for ML model development are examined. The concepts of artificial intelligence, ML, and deep learning and their drug applications are explored in schistosomiasis. The use of binary classification in predicting antischistosomal compounds and some algorithms that have been applied including random forest and naive Bayesian are discussed. For this review, some deep learning algorithms (deep neural networks) are proposed as novel algorithms for predicting antischistosomal molecules via binary classification. Databases specifically designed for housing bioactivity data on antischistosomal molecules enriched with functional genomic datasets and ontologies are thus urgently needed for developing predictive ML models. This shows the application of machine learning techniques for the discovery of novel antischistosomal small molecules via binary classification in the era of big data.

ACS Style

Samuel K. Kwofie; Kwasi Agyenkwa-Mawuli; Emmanuel Broni; Whelton A. Miller Iii; Michael D. Wilson. Prediction of antischistosomal small molecules using machine learning in the era of big data. Molecular Diversity 2021, 1 -11.

AMA Style

Samuel K. Kwofie, Kwasi Agyenkwa-Mawuli, Emmanuel Broni, Whelton A. Miller Iii, Michael D. Wilson. Prediction of antischistosomal small molecules using machine learning in the era of big data. Molecular Diversity. 2021; ():1-11.

Chicago/Turabian Style

Samuel K. Kwofie; Kwasi Agyenkwa-Mawuli; Emmanuel Broni; Whelton A. Miller Iii; Michael D. Wilson. 2021. "Prediction of antischistosomal small molecules using machine learning in the era of big data." Molecular Diversity , no. : 1-11.

Review
Published: 14 July 2021 in Natural Products and Bioprospecting
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Despite advancements in the areas of omics and chemoinformatics, potent novel biotherapeutic molecules with new modes of actions are needed for leishmaniasis. The socioeconomic burden of leishmaniasis remains alarming in endemic regions. Currently, reports from existing endemic areas such as Nepal, Iran, Brazil, India, Sudan and Afghanistan, as well as newly affected countries such as Peru, Bolivia and Somalia indicate concerns of chemoresistance to the classical antimonial treatment. As a result, effective antileishmanial agents which are safe and affordable are urgently needed. Natural products from both flora and fauna have contributed immensely to chemotherapeutics and serve as vital sources of new chemical agents. This review focuses on a systematic cross-sectional view of all characterized anti-leishmanial compounds from natural sources over the last decade. Furthermore, IC50/EC50, cytotoxicity and suggested mechanisms of action of some of these natural products are provided. The natural product classification includes alkaloids, terpenes, terpenoids, and phenolics. The plethora of reported mechanisms involve calcium channel inhibition, immunomodulation and apoptosis. Making available enriched data pertaining to bioactivity and mechanisms of natural products complement current efforts geared towards unraveling potent leishmanicides of therapeutic relevance. Graphic Abstract

ACS Style

Patrick O. Sakyi; Richard K. Amewu; Robert N. O. A. Devine; Emahi Ismaila; Whelton A. Miller; Samuel K. Kwofie. The Search for Putative Hits in Combating Leishmaniasis: The Contributions of Natural Products Over the Last Decade. Natural Products and Bioprospecting 2021, 1 -56.

AMA Style

Patrick O. Sakyi, Richard K. Amewu, Robert N. O. A. Devine, Emahi Ismaila, Whelton A. Miller, Samuel K. Kwofie. The Search for Putative Hits in Combating Leishmaniasis: The Contributions of Natural Products Over the Last Decade. Natural Products and Bioprospecting. 2021; ():1-56.

Chicago/Turabian Style

Patrick O. Sakyi; Richard K. Amewu; Robert N. O. A. Devine; Emahi Ismaila; Whelton A. Miller; Samuel K. Kwofie. 2021. "The Search for Putative Hits in Combating Leishmaniasis: The Contributions of Natural Products Over the Last Decade." Natural Products and Bioprospecting , no. : 1-56.

Journal article
Published: 29 April 2021 in Biomolecules
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Severely ill coronavirus disease 2019 (COVID-19) patients show elevated concentrations of pro-inflammatory cytokines, a situation commonly known as a cytokine storm. The p38 MAPK receptor is considered a plausible therapeutic target because of its involvement in the platelet activation processes leading to inflammation. This study aimed to identify potential natural product-derived inhibitory molecules against the p38α MAPK receptor to mitigate the eliciting of pro-inflammatory cytokines using computational techniques. The 3D X-ray structure of the receptor with PDB ID 3ZS5 was energy minimized using GROMACS and used for molecular docking via AutoDock Vina. The molecular docking was validated with an acceptable area under the curve (AUC) of 0.704, which was computed from the receiver operating characteristic (ROC) curve. A compendium of 38,271 natural products originating from Africa and China together with eleven known p38 MAPK inhibitors were screened against the receptor. Four potential lead compounds ZINC1691180, ZINC5519433, ZINC4520996 and ZINC5733756 were identified. The compounds formed strong intermolecular bonds with critical residues Val38, Ala51, Lys53, Thr106, Leu108, Met109 and Phe169. Additionally, they exhibited appreciably low binding energies which were corroborated via molecular mechanics Poisson–Boltzmann surface area (MM-PBSA) calculations. The compounds were also predicted to have plausible pharmacological profiles with insignificant toxicity. The molecules were also predicted to be anti-inflammatory, kinase inhibitors, antiviral, platelet aggregation inhibitors, and immunosuppressive, with probable activity (Pa) greater than probable inactivity (Pi). ZINC5733756 is structurally similar to estradiol with a Tanimoto coefficient value of 0.73, which exhibits anti-inflammatory activity by targeting the activation of Nrf2. Similarly, ZINC1691180 has been reported to elicit anti-inflammatory activity in vitro. The compounds may serve as scaffolds for the design of potential biotherapeutic molecules against the cytokine storm associated with COVID-19.

ACS Style

Seth Asiedu; Samuel Kwofie; Emmanuel Broni; Michael Wilson. Computational Identification of Potential Anti-Inflammatory Natural Compounds Targeting the p38 Mitogen-Activated Protein Kinase (MAPK): Implications for COVID-19-Induced Cytokine Storm. Biomolecules 2021, 11, 653 .

AMA Style

Seth Asiedu, Samuel Kwofie, Emmanuel Broni, Michael Wilson. Computational Identification of Potential Anti-Inflammatory Natural Compounds Targeting the p38 Mitogen-Activated Protein Kinase (MAPK): Implications for COVID-19-Induced Cytokine Storm. Biomolecules. 2021; 11 (5):653.

Chicago/Turabian Style

Seth Asiedu; Samuel Kwofie; Emmanuel Broni; Michael Wilson. 2021. "Computational Identification of Potential Anti-Inflammatory Natural Compounds Targeting the p38 Mitogen-Activated Protein Kinase (MAPK): Implications for COVID-19-Induced Cytokine Storm." Biomolecules 11, no. 5: 653.

Review article
Published: 24 April 2021 in Journal of Parasitic Diseases
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The mortality rate of leishmaniasis is increasing at an alarming rate and is currently second to malaria amongst the other neglected tropical diseases. Unfortunately, many governments and key stakeholders are not investing enough in the development of new therapeutic interventions. The available treatment options targeting different pathways of the parasite have seen inefficiencies, drug resistance, and toxic side effects coupled with longer treatment durations. Numerous studies to understand the biochemistry of leishmaniasis and its pathogenesis have identified druggable targets including ornithine decarboxylase, trypanothione reductase, and pteridine reductase, which are relevant for the survival and growth of the parasites. Another plausible target is the sterol biosynthetic pathway; however, this has not been fully investigated. Sterol biosynthesis is essential for the survival of the Leishmania species because its inhibition could lead to the death of the parasites. This review seeks to evaluate how critical the enzymes involved in sterol biosynthetic pathway are to the survival of the leishmania parasite. The review also highlights both synthetic and natural product compounds with their IC50 values against selected enzymes. Finally, recent advancements in drug design strategies targeting the sterol biosynthesis pathway of Leishmania are discussed.

ACS Style

Patrick O. Sakyi; Richard K. Amewu; Robert N. O. A. Devine; Alfred K. Bienibuor; Whelton A. Miller; Samuel K. Kwofie. Unravelling the myth surrounding sterol biosynthesis as plausible target for drug design against leishmaniasis. Journal of Parasitic Diseases 2021, 1 -20.

AMA Style

Patrick O. Sakyi, Richard K. Amewu, Robert N. O. A. Devine, Alfred K. Bienibuor, Whelton A. Miller, Samuel K. Kwofie. Unravelling the myth surrounding sterol biosynthesis as plausible target for drug design against leishmaniasis. Journal of Parasitic Diseases. 2021; ():1-20.

Chicago/Turabian Style

Patrick O. Sakyi; Richard K. Amewu; Robert N. O. A. Devine; Alfred K. Bienibuor; Whelton A. Miller; Samuel K. Kwofie. 2021. "Unravelling the myth surrounding sterol biosynthesis as plausible target for drug design against leishmaniasis." Journal of Parasitic Diseases , no. : 1-20.

Review article
Published: 10 April 2021 in The Scientific World Journal
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Background. Till date, there is no known antidote to cure diabetes mellitus despite the discovery and development of diverse pharmacotherapeutic agents many years ago. Technological advancement in natural product chemistry has led to the isolation of analogs of vitexin and isovitexin found in diverse bioresources. These compounds have been extensively studied to explore their pharmacological relevance in diabetes mellitus. Aim of the Study. The present review was to compile results from in vitro and in vivo studies performed with vitexin and isovitexin derivatives relating to diabetes mellitus and its complications. A systematic online literature query was executed to collect all relevant articles published up to March 2020. Results. In this piece, we have collected data and presented it in a one-stop document to support the multitargeted mechanistic actions of vitexin and isovitexin in controlling diabetes mellitus and its complications. Conclusion. Data collected hint that vitexin and isovitexin work by targeting diverse pathophysiological and metabolic pathways and molecular drug points involved in the clinical manifestations of diabetes mellitus. This is expected to provide a deeper understanding of its actions and also serve as a catapult for clinical trials and application research.

ACS Style

Ibrahim Luru Abdulai; Samuel Kojo Kwofie; Winfred Seth Gbewonyo; Daniel Boison; Joshua Buer Puplampu; Michael Buenor Adinortey. Multitargeted Effects of Vitexin and Isovitexin on Diabetes Mellitus and Its Complications. The Scientific World Journal 2021, 2021, 1 -20.

AMA Style

Ibrahim Luru Abdulai, Samuel Kojo Kwofie, Winfred Seth Gbewonyo, Daniel Boison, Joshua Buer Puplampu, Michael Buenor Adinortey. Multitargeted Effects of Vitexin and Isovitexin on Diabetes Mellitus and Its Complications. The Scientific World Journal. 2021; 2021 ():1-20.

Chicago/Turabian Style

Ibrahim Luru Abdulai; Samuel Kojo Kwofie; Winfred Seth Gbewonyo; Daniel Boison; Joshua Buer Puplampu; Michael Buenor Adinortey. 2021. "Multitargeted Effects of Vitexin and Isovitexin on Diabetes Mellitus and Its Complications." The Scientific World Journal 2021, no. : 1-20.

Journal article
Published: 18 March 2021 in Biomolecules
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The huge burden of leishmaniasis caused by the trypanosomatid protozoan parasite Leishmania is well known. This illness was included in the list of neglected tropical diseases targeted for elimination by the World Health Organization. However, the increasing evidence of resistance to existing antimonial drugs has made the eradication of the disease difficult to achieve, thus warranting the search for new drug targets. We report here studies that used computational methods to identify inhibitors of receptors from natural products. The cell division cycle-2-related kinase 12 (CRK12) receptor is a plausible drug target against Leishmania donovani. This study modelled the 3D molecular structure of the L. donovani CRK12 (LdCRK12) and screened for small molecules with potential inhibitory activity from African flora. An integrated library of 7722 African natural product-derived compounds and known inhibitors were screened against the LdCRK12 using AutoDock Vina after performing energy minimization with GROMACS 2018. Four natural products, namely sesamin (NANPDB1649), methyl ellagic acid (NANPDB1406), stylopine (NANPDB2581), and sennecicannabine (NANPDB6446) were found to be potential LdCRK12 inhibitory molecules. The molecular docking studies revealed two compounds NANPDB1406 and NANPDB2581 with binding affinities of −9.5 and −9.2 kcal/mol, respectively, against LdCRK12 which were higher than those of the known inhibitors and drugs, including GSK3186899, amphotericin B, miltefosine, and paromomycin. All the four compounds were predicted to have inhibitory constant (Ki) values ranging from 0.108 to 0.587 μM. NANPDB2581, NANPDB1649 and NANPDB1406 were also predicted as antileishmanial with Pa and Pi values of 0.415 and 0.043, 0.391 and 0.052, and 0.351 and 0.071, respectively. Molecular dynamics simulations coupled with molecular mechanics Poisson–Boltzmann surface area (MM/PBSA) computations reinforced their good binding mechanisms. Most compounds were observed to bind in the ATP binding pocket of the kinase domain. Lys488 was predicted as a key residue critical for ligand binding in the ATP binding pocket of the LdCRK12. The molecules were pharmacologically profiled as druglike with inconsequential toxicity. The identified molecules have scaffolds that could form the backbone for fragment-based drug design of novel leishmanicides but warrant further studies to evaluate their therapeutic potential.

ACS Style

Emmanuel Broni; Samuel Kwofie; Seth Asiedu; Whelton Miller; Michael Wilson. A Molecular Modeling Approach to Identify Potential Antileishmanial Compounds Against the Cell Division Cycle (cdc)-2-Related Kinase 12 (CRK12) Receptor of Leishmania donovani. Biomolecules 2021, 11, 458 .

AMA Style

Emmanuel Broni, Samuel Kwofie, Seth Asiedu, Whelton Miller, Michael Wilson. A Molecular Modeling Approach to Identify Potential Antileishmanial Compounds Against the Cell Division Cycle (cdc)-2-Related Kinase 12 (CRK12) Receptor of Leishmania donovani. Biomolecules. 2021; 11 (3):458.

Chicago/Turabian Style

Emmanuel Broni; Samuel Kwofie; Seth Asiedu; Whelton Miller; Michael Wilson. 2021. "A Molecular Modeling Approach to Identify Potential Antileishmanial Compounds Against the Cell Division Cycle (cdc)-2-Related Kinase 12 (CRK12) Receptor of Leishmania donovani." Biomolecules 11, no. 3: 458.

Journal article
Published: 12 March 2021 in Computation
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Buruli ulcer caused by Mycobacterium ulcerans (M. ulcerans) is identified by a pain-free cyst or edema which develops into a massive skin ulcer if left untreated. There are reports of chemoresistance, toxicity, noncompliance, and poor efficacy of current therapeutic options. Previously, we used cheminformatics approaches to identify potential antimycobacterial compounds targeting major receptors in M. ulcerans. In this paper, we sought to identify potential bioactive compounds by targeting Cystathionine gamma-synthase (CGS) MetB, a key receptor involved in methionine synthesis. Inhibition of methionine synthesis restricts the growth of M. ulcerans. Two potent inhibitors Juglone (IC50 0.7 +/− 0.7 µmol/L) and 9-hydroxy-alpha-lapachone (IC50 0.9 +/− 0.1 µmol/L) were used to generate 3D chemical feature pharmacophore model via LigandScout with a score of 0.9719. The validated model was screened against a pre-filtered library of 2530 African natural products. Compounds with fit scores above 66.40 were docked against the structure of CGS to generate hits. Three compounds, namely Gentisic 5-O glucoside (an isolate of African tree Alchornea cordifolia), Isoscutellarein (an isolate of Theobroma plant) and ZINC05854400, were identified as potential bioactive molecules with high binding affinities of −7.1, −8.4 and −8.4 kcal/mol against CGS, respectively. Novel structural insight into the binding mechanisms was elucidated using LigPlot+ and molecular dynamics simulations. All three molecules were predicted to possess antibacterial, anti-ulcerative, and dermatological properties. These compounds have the propensity to disrupt the methionine synthesis mechanisms with the potential of stagnating the growth of M. ulcerans. As a result of reasonably good pharmacological profiling, the three drug-like compounds are potential novel scaffolds that can be optimized into antimycobacterial molecules.

ACS Style

Samuel Kwofie; Nigel Dolling; Emmanuel Donkoh; Godwin Laryea; Lydia Mosi; Whelton Miller; Michael Adinortey; Michael Wilson. Pharmacophore-Guided Identification of Natural Products as Potential Inhibitors of Mycobacterium ulcerans Cystathionine γ-Synthase MetB. Computation 2021, 9, 32 .

AMA Style

Samuel Kwofie, Nigel Dolling, Emmanuel Donkoh, Godwin Laryea, Lydia Mosi, Whelton Miller, Michael Adinortey, Michael Wilson. Pharmacophore-Guided Identification of Natural Products as Potential Inhibitors of Mycobacterium ulcerans Cystathionine γ-Synthase MetB. Computation. 2021; 9 (3):32.

Chicago/Turabian Style

Samuel Kwofie; Nigel Dolling; Emmanuel Donkoh; Godwin Laryea; Lydia Mosi; Whelton Miller; Michael Adinortey; Michael Wilson. 2021. "Pharmacophore-Guided Identification of Natural Products as Potential Inhibitors of Mycobacterium ulcerans Cystathionine γ-Synthase MetB." Computation 9, no. 3: 32.

Journal article
Published: 14 January 2021 in Molecules
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The coronavirus disease 2019 (COVID-19) pandemic caused by the severe acute respiratory syndrome virus 2 (SARS-CoV-2) has impacted negatively on public health and socioeconomic status, globally. Although, there are currently no specific drugs approved, several existing drugs are being repurposed, but their successful outcomes are not guaranteed. Therefore, the search for novel therapeutics remains a priority. We screened for inhibitors of the SARS-CoV-2 main protease and the receptor-binding domain of the spike protein from an integrated library of African natural products, compounds generated from machine learning studies and antiviral drugs using AutoDock Vina. The binding mechanisms between the compounds and the proteins were characterized using LigPlot+ and molecular dynamics simulations techniques. The biological activities of the hit compounds were also predicted using a Bayesian-based approach. Six potential bioactive molecules NANPDB2245, NANPDB2403, fusidic acid, ZINC000095486008, ZINC0000556656943 and ZINC001645993538 were identified, all of which had plausible binding mechanisms with both viral receptors. Molecular dynamics simulations, including molecular mechanics Poisson-Boltzmann surface area (MM/PBSA) computations revealed stable protein–ligand complexes with all the compounds having acceptable free binding energies <−15 kJ/mol with each receptor. NANPDB2245, NANPDB2403 and ZINC000095486008 were predicted as antivirals; ZINC000095486008 as a membrane permeability inhibitor; NANPDB2403 as a cell adhesion inhibitor and RNA-directed RNA polymerase inhibitor; and NANPDB2245 as a membrane integrity antagonist. Therefore, they have the potential to inhibit viral entry and replication. These drug-like molecules were predicted to possess attractive pharmacological profiles with negligible toxicity. Novel critical residues identified for both targets could aid in a better understanding of the binding mechanisms and design of fragment-based de novo inhibitors. The compounds are proposed as worthy of further in vitro assaying and as scaffolds for the development of novel SARS-CoV-2 therapeutic molecules.

ACS Style

Samuel Kwofie; Emmanuel Broni; Seth Asiedu; Gabriel Kwarko; Bismark Dankwa; Kweku Enninful; Elvis Tiburu; Michael Wilson. Cheminformatics-Based Identification of Potential Novel Anti-SARS-CoV-2 Natural Compounds of African Origin. Molecules 2021, 26, 406 .

AMA Style

Samuel Kwofie, Emmanuel Broni, Seth Asiedu, Gabriel Kwarko, Bismark Dankwa, Kweku Enninful, Elvis Tiburu, Michael Wilson. Cheminformatics-Based Identification of Potential Novel Anti-SARS-CoV-2 Natural Compounds of African Origin. Molecules. 2021; 26 (2):406.

Chicago/Turabian Style

Samuel Kwofie; Emmanuel Broni; Seth Asiedu; Gabriel Kwarko; Bismark Dankwa; Kweku Enninful; Elvis Tiburu; Michael Wilson. 2021. "Cheminformatics-Based Identification of Potential Novel Anti-SARS-CoV-2 Natural Compounds of African Origin." Molecules 26, no. 2: 406.

Original research article
Published: 25 May 2020 in Frontiers in Pharmacology
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Leishmania is a parasitic protozoon responsible for the neglected tropical disease Leishmaniasis. Approximately, 350 million people are susceptible and close to 70,000 death cases globally are reported annually. The lack of effective leishmanicides, the emergence of drug resistance and toxicity concerns necessitate the pursuit for effective antileishmanial drugs. Natural compounds serve as reservoirs for discovering new drugs due to their chemical diversity. Hardwickiic acid (HA) isolated from the stembark of Croton sylvaticus was evaluated for its leishmanicidal potential against Leishmania donovani and L. major promastigotes. The susceptibility of the promastigotes to HA was determined using the 3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyltetrazolium bromide/phenazine methosulfate colorimetric assay with Amphotericin B serving as positive control. HA showed a significant antileishmanial activity on L. donovani promastigotes with an IC50 value of 31.57± 0.06 µM with respect to the control drug, amphotericin B with IC50 of 3.35 ± 0.14 µM). The cytotoxic activity was observed to be CC50 = 247.83 ± 6.32 µM against 29.99 ± 2.82 µM for curcumin, the control, resulting in a selectivity index of SI = 7.85. Molecular modeling, docking and dynamics simulations of selected drug targets corroborated the observed antileishmanial activity of HA. Novel insights into the mechanisms of binding were obtained for trypanothione reductase (TR), pteridine reductase 1 (PTR1), and glutamate cysteine ligase (GCL). The binding affinity of HA to the drug targets LmGCL, LmPTR1, LdTR, LmTR, LdGCL, and LdPTR1 were obtained as -8.0, -7.8, -7.6, -7.5, -7.4 and -7.1 kcal/mol, respectively. The role of Lys16, Ser111, and Arg17 as critical residues required for binding to LdPTR1 was reinforced. HA was predicted as a Caspase-3 stimulant and Caspase-8 stimulant, implying a possible role in apoptosis, which was shown experimentally that HA induced parasite death by loss of membrane integrity. HA was also predicted as antileishmanial molecule corroborating the experimental activity. Therefore, HA is a promising antileishmanial molecule worthy of further development as a biotherapeutic agent.

ACS Style

Justice Afrifa Crentsil; Lauve Rachel Tchokouaha Yamthe; Barbara Zenabu Anibea; Emmanuel Broni; Samuel Kojo Kwofie; John Kweku Amissah Tetteh; Dorcas Osei-Safo. Leishmanicidal Potential of Hardwickiic Acid Isolated From Croton sylvaticus. Frontiers in Pharmacology 2020, 11, 1 .

AMA Style

Justice Afrifa Crentsil, Lauve Rachel Tchokouaha Yamthe, Barbara Zenabu Anibea, Emmanuel Broni, Samuel Kojo Kwofie, John Kweku Amissah Tetteh, Dorcas Osei-Safo. Leishmanicidal Potential of Hardwickiic Acid Isolated From Croton sylvaticus. Frontiers in Pharmacology. 2020; 11 ():1.

Chicago/Turabian Style

Justice Afrifa Crentsil; Lauve Rachel Tchokouaha Yamthe; Barbara Zenabu Anibea; Emmanuel Broni; Samuel Kojo Kwofie; John Kweku Amissah Tetteh; Dorcas Osei-Safo. 2020. "Leishmanicidal Potential of Hardwickiic Acid Isolated From Croton sylvaticus." Frontiers in Pharmacology 11, no. : 1.

Journal article
Published: 23 May 2020 in Computers in Biology and Medicine
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The outer membrane protein A (OmpATb) of Mycobacterium tuberculosis is a virulence factor that neutralizes the host pH to impede the uptake of hydrophilic antitubercular drugs. Identifying natural compounds with the potential to inhibit OmpATb could allow circumvention of the porin-like activities of OmpATb. Four potential leads comprising ZINC000003958185, ZINC000000157405, ZINC000000001392 and ZINC000034268676 were obtained by virtual screening of 6394 diverse natural products. Characterization of the binding interactions of the potential leads with OmpATb revealed nine critical residues comprising ARG86, LEU110, LEU113, LEU114, ALA115, PHE142, SER145, VAL146, and PHE151. Molecular dynamics simulations also revealed very stable protein-lead complexes. Most residues contributed lower binding energies to the overall molecular mechanics Poisson–Boltzmann surface area (MM-PBSA) binding free energies of the interactions between the molecules and OmpATb protein. Induced Fit Docking (IFD) of the compounds regenerated poses of the molecular docking using AutoDock Vina. These molecules could be starting templates for designing inhibitors to bypass the pore mediating activities of OmpATb. Based on structural similarity, ZINC000034268676 was suggested as a potential scaffold for designing efflux pump inhibitors of the gate mediating activities of OmpATb and may enhance the uptake of hydrophilic drugs to reduce the duration time of tuberculosis treatment. Furthermore, structurally similar compounds available in the DrugBank database with a similarity threshold of 0.7 have been reported to exhibit antitubercular and anti-mycobacterial activities. These biomolecules can be further characterized experimentally to corroborate their antitubercular activity. Also, the skeletons of the molecules can be adopted as sub-structures for the design of future anti-mycobacterial drugs.

ACS Style

Samuel K. Kwofie; Courage Adobor; Erasmus Quansah; Joana Bentil; Michael Ampadu; Whelton A. Miller; Michael D. Wilson. Molecular docking and dynamics simulations studies of OmpATb identifies four potential novel natural product-derived anti-Mycobacterium tuberculosis compounds. Computers in Biology and Medicine 2020, 122, 103811 .

AMA Style

Samuel K. Kwofie, Courage Adobor, Erasmus Quansah, Joana Bentil, Michael Ampadu, Whelton A. Miller, Michael D. Wilson. Molecular docking and dynamics simulations studies of OmpATb identifies four potential novel natural product-derived anti-Mycobacterium tuberculosis compounds. Computers in Biology and Medicine. 2020; 122 ():103811.

Chicago/Turabian Style

Samuel K. Kwofie; Courage Adobor; Erasmus Quansah; Joana Bentil; Michael Ampadu; Whelton A. Miller; Michael D. Wilson. 2020. "Molecular docking and dynamics simulations studies of OmpATb identifies four potential novel natural product-derived anti-Mycobacterium tuberculosis compounds." Computers in Biology and Medicine 122, no. : 103811.

Journal article
Published: 28 August 2019 in Computers in Biology and Medicine
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The impact of Ebola virus disease (EVD) is devastating with concomitant high fatalities. Currently, various drugs and vaccines are at different stages of development, corroborating the need to identify new therapeutic molecules. The VP24 protein of the Ebola virus (EBOV) plays a key role in the pathology and replication of the EVD. The VP24 protein interferes with the host immune response to viral infections and promotes nucleocapsid formation, thus making it a viable drug target. This study sought to identify putative lead compounds from the African flora with potential to inhibit the activity of the EBOV VP24 protein using pharmacoinformatics and molecular docking. An integrated library of 7675 natural products originating from Africa obtained from the AfroDB and NANPDB databases, as well as known inhibitors were screened against VP24 (PDB ID: 4M0Q) utilising AutoDock Vina after energy minimization using GROMACS. The top 19 compounds were physicochemically and pharmacologically profiled using ADMET Predictor™, SwissADME and DataWarrior. The mechanisms of binding between the molecules and EBOV VP24 were characterised using LigPlot+. The performance of the molecular docking was evaluated by generating a receiver operating characteristic (ROC) by screening known inhibitors and decoys against EBOV VP24. The prediction of activity spectra for substances (PASS) and machine learning-based Open Bayesian models were used to predict the anti-viral and anti-Ebola activity of the molecules, respectively. Four natural products, namely, ZINC000095486070, ZINC000003594643, ZINC000095486008 and sarcophine were found to be potential EBOV VP24-inhibitiory molecules. The molecular docking results showed that ZINC000095486070 had high binding affinity of −9.7 kcal/mol with EBOV VP24, which was greater than those of the known VP24-inhibitors used as standards in the study including Ouabain, Nilotinib, Clomiphene, Torimefene, Miglustat and BCX4430. The area under the curve of the generated ROC for evaluating the performance of the molecular docking was 0.77, which was considered acceptable. The predicted promising molecules were also validated using induced-fit docking with the receptor using Schrödinger and molecular mechanics Poisson-Boltzmann surface area (MM-PBSA) calculations. The molecules had better binding mechanisms and were pharmacologically profiled to have plausible efficacies, negligible toxicity as well as suitable for designing anti-Ebola scaffolds. ZINC000095486008 and sarcophine (NANPDB135) were predicted to possess anti-viral activity, while ZINC000095486070 and ZINC000003594643 to be anti-Ebola compounds. The identified compounds are potential inhibitors worthy of further development as EBOV biotherapeutic agents. The scaffolds of the compounds could also serve as building blocks for designing novel Ebola inhibitors.

ACS Style

Samuel K. Kwofie; Emmanuel Broni; Joshua Teye; Erasmus Quansah; Ibrahim Issah; Michael D. Wilson; Whelton Miller; Elvis K. Tiburu; Joseph H.K. Bonney. Pharmacoinformatics-based identification of potential bioactive compounds against Ebola virus protein VP24. Computers in Biology and Medicine 2019, 113, 103414 .

AMA Style

Samuel K. Kwofie, Emmanuel Broni, Joshua Teye, Erasmus Quansah, Ibrahim Issah, Michael D. Wilson, Whelton Miller, Elvis K. Tiburu, Joseph H.K. Bonney. Pharmacoinformatics-based identification of potential bioactive compounds against Ebola virus protein VP24. Computers in Biology and Medicine. 2019; 113 ():103414.

Chicago/Turabian Style

Samuel K. Kwofie; Emmanuel Broni; Joshua Teye; Erasmus Quansah; Ibrahim Issah; Michael D. Wilson; Whelton Miller; Elvis K. Tiburu; Joseph H.K. Bonney. 2019. "Pharmacoinformatics-based identification of potential bioactive compounds against Ebola virus protein VP24." Computers in Biology and Medicine 113, no. : 103414.

Journal article
Published: 21 June 2019 in Molecules
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Buruli ulcer is a neglected tropical disease caused by the bacterium Mycobacterium ulcerans. Its virulence is attributed to the dermo-necrotic polyketide toxin mycolactone, whose synthesis is regressed when its iron acquisition system regulated by the iron-dependent regulator (ideR) is deactivated. Interfering with the activation mechanism of ideR to inhibit the toxin's synthesis could serve as a possible cure for Buruli ulcer. The three-dimensional structure of the ideR for Mycobacterium ulcerans was generated using homology modeling. A library of 832 African natural products (AfroDB), as well as five known anti-mycobacterial compounds were docked against the metal binding site of the ideR. The area under the curve (AUC) values greater than 0.7 were obtained for the computed Receiver Operating Characteristics (ROC) curves, validating the docking protocol. The identified top hits were pharmacologically profiled using Absorption, Distribution, Metabolism, Elimination and Toxicity (ADMET) predictions and their binding mechanisms were characterized. Four compounds with ZINC IDs ZINC000018185774, ZINC000095485921, ZINC000014417338 and ZINC000005357841 emerged as leads with binding energies of -7.7 kcal/mol, -7.6 kcal/mol, -8.0 kcal/mol and -7.4 kcal/mol, respectively. Induced Fit Docking (IFD) was also performed to account for the protein's flexibility upon ligand binding and to estimate the best plausible conformation of the complexes. Results obtained from the IFD were consistent with that of the molecular docking with the lead compounds forming interactions with known essential residues and some novel critical residues Thr14, Arg33 and Asp17. A hundred nanoseconds molecular dynamic simulations of the unbound ideR and its complexes with the respective lead compounds revealed changes in the ideR's conformations induced by ZINC000018185774. Comparison of the lead compounds to reported potent inhibitors by docking them against the DNA-binding domain of the protein also showed the lead compounds to have very close binding affinities to those of the potent inhibitors. Interestingly, structurally similar compounds to ZINC000018185774 and ZINC000014417338, as well as analogues of ZINC000095485921, including quercetin are reported to possess anti-mycobacterial activity. Also, ZINC000005357841 was predicted to possess anti-inflammatory and anti-oxidative activities, which are relevant in Buruli ulcer and iron acquisition mechanisms, respectively. The leads are molecular templates which may serve as essential scaffolds for the design of future anti-mycobacterium ulcerans agents.

ACS Style

Samuel K. Kwofie; Kweku S. Enninful; Jaleel A. Yussif; Lina A. Asante; Mavis Adjei; Kwabena Kan-Dapaah; Elvis K. Tiburu; Wilhelmina A. Mensah; Whelton A. Miller; Lydia Mosi; Michael D. Wilson. Molecular Informatics Studies of the Iron-Dependent Regulator (ideR) Reveal Potential Novel Anti-Mycobacterium ulcerans Natural Product-Derived Compounds. Molecules 2019, 24, 2299 .

AMA Style

Samuel K. Kwofie, Kweku S. Enninful, Jaleel A. Yussif, Lina A. Asante, Mavis Adjei, Kwabena Kan-Dapaah, Elvis K. Tiburu, Wilhelmina A. Mensah, Whelton A. Miller, Lydia Mosi, Michael D. Wilson. Molecular Informatics Studies of the Iron-Dependent Regulator (ideR) Reveal Potential Novel Anti-Mycobacterium ulcerans Natural Product-Derived Compounds. Molecules. 2019; 24 (12):2299.

Chicago/Turabian Style

Samuel K. Kwofie; Kweku S. Enninful; Jaleel A. Yussif; Lina A. Asante; Mavis Adjei; Kwabena Kan-Dapaah; Elvis K. Tiburu; Wilhelmina A. Mensah; Whelton A. Miller; Lydia Mosi; Michael D. Wilson. 2019. "Molecular Informatics Studies of the Iron-Dependent Regulator (ideR) Reveal Potential Novel Anti-Mycobacterium ulcerans Natural Product-Derived Compounds." Molecules 24, no. 12: 2299.

Journal article
Published: 25 March 2019 in Toxins
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Ulcers due to infections with Mycobacterium ulcerans are characterized by complete lack of wound healing processes, painless, an underlying bed of host dead cells and undermined edges due to necrosis. Mycolactone, a macrolide produced by the mycobacterium, is believed to be the toxin responsible. Of interest and relevance is the knowledge that Buruli ulcer (BU) patients remember experiencing trauma previously at the site of the ulcers, suggesting an impairment of wound healing processes, the plausible effect due to the toxin. Wound healing processes involve activation of the blood platelets to release the contents of the dense granules mainly serotonin, calcium ions, and ADP/ATP by exocytosis into the bloodstream. The serotonin release results in attracting more platelets and mast cells to the wound site, with the mast cells also undergoing degranulation, releasing compounds into the bloodstream by exocytosis. Recent work has identified interference in the co-translational translocation of many secreted proteins via the endoplasmic reticulum and cell death involving Wiskott-Aldrich syndrome protein (WASP), Sec61, and angiotensin II receptors (AT2R). We hypothesized that mycolactone by being lipophilic, passively crosses cell membranes and binds to key proteins that are involved in exocytosis by platelets and mast cells, thus inhibiting the initiation of wound healing processes. Based on this, molecular docking studies were performed with mycolactone against key soluble n-ethylmaleimide-sensitive factor attachment protein receptor (SNARE) proteins and regulators, namely Vesicle-associated membrane protein (VAMP8), Synaptosomal-associated protein (SNAP23, syntaxin 11, Munc13-4 (its isoform Munc13-1 was used), and Munc18b; and also against known mycolactone targets (Sec61, AT2R, and WASP). Munc18b was shown to be a plausible mycolactone target after the molecular docking studies with binding affinity of −8.5 kcal/mol. Structural studies and molecular mechanics Poisson-Boltzmann surface area (MM-PBSA) binding energy calculations of the mycolactone and Munc18b complex was done with 100 ns molecular dynamics simulations using GROMACS. Mycolactone binds strongly to Munc18b with an average binding energy of −247.571 ± 37.471 kJ/mol, and its presence elicits changes in the structural conformation of the protein. Analysis of the binding interactions also shows that mycolactone interacts with Arg405, which is an important residue of Munc18b, whose mutation could result in impaired granule exocytosis. These findings consolidate the possibility that Munc18b could be a target of mycolactone. The implication of the interaction can be experimentally evaluated to further understand its role in granule exocytosis impairment in Buruli ulcer.

ACS Style

Samuel K. Kwofie; Bismark Dankwa; Kweku S. Enninful; Courage Adobor; Emmanuel Broni; Alfred Ntiamoah; Michael D. Wilson. Molecular Docking and Dynamics Simulation Studies Predict Munc18b as a Target of Mycolactone: A Plausible Mechanism for Granule Exocytosis Impairment in Buruli Ulcer Pathogenesis. Toxins 2019, 11, 181 .

AMA Style

Samuel K. Kwofie, Bismark Dankwa, Kweku S. Enninful, Courage Adobor, Emmanuel Broni, Alfred Ntiamoah, Michael D. Wilson. Molecular Docking and Dynamics Simulation Studies Predict Munc18b as a Target of Mycolactone: A Plausible Mechanism for Granule Exocytosis Impairment in Buruli Ulcer Pathogenesis. Toxins. 2019; 11 (3):181.

Chicago/Turabian Style

Samuel K. Kwofie; Bismark Dankwa; Kweku S. Enninful; Courage Adobor; Emmanuel Broni; Alfred Ntiamoah; Michael D. Wilson. 2019. "Molecular Docking and Dynamics Simulation Studies Predict Munc18b as a Target of Mycolactone: A Plausible Mechanism for Granule Exocytosis Impairment in Buruli Ulcer Pathogenesis." Toxins 11, no. 3: 181.

Journal article
Published: 20 March 2019 in Biosensors
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Dioclea reflexa bioactive compounds have been shown to contain antioxidant properties. The extracts from the same plant are used in traditional medical practices to treat various diseases with impressive outcomes. In this study, ionic mobility in Saccharomyces cerevisiae cells in the presence of D. reflexa seed extracts was monitored using electrochemical detection methods to link cell death to ionic imbalance. Cells treated with ethanol, methanol, and water extracts were studied using cyclic voltammetry and cell counting to correlate electrochemical behavior and cell viability, respectively. The results were compared with cells treated with pore-forming Amphotericin b (Amp b), as well as Fluconazole (Flu) and the antimicrobial drug Rifampicin (Rif). The D. reflexa seed water extract (SWE) revealed higher anodic peak current with 58% cell death. Seed methanol extract (SME) and seed ethanol extract (SEE) recorded 31% and 22% cell death, respectively. Among the three control drugs, Flu revealed the highest cell death of about 64%, whereas Amp b and Rif exhibited cell deaths of 35% and 16%, respectively, after 8 h of cell growth. It was observed that similar to SWE, there was an increase in the anodic peak current in the presence of different concentrations of Amp b, which also correlated with enhanced cell death. It was concluded from this observation that Amp b and SWE might follow similar mechanisms to inhibit cell growth. Thus, the individual bioactive compounds from the water extracts of D. reflexa seeds could further be purified and tested to validate their potential therapeutic application. The strategy to link electrochemical behavior to biochemical responses could be a simple, fast, and robust screening technique for new drug targets and to understand the mechanism of action of such drugs against disease models.

ACS Style

Patrick Kobina Arthur; Anthony Boadi Yeboah; Ibrahim Issah; Srinivasan Balapangu; Samuel K. Kwofie; Bernard O. Asimeng; E. Johan Foster; Elvis K. Tiburu. Electrochemical Response of Saccharomyces cerevisiae Corresponds to Cell Viability upon Exposure to Dioclea reflexa Seed Extracts and Antifungal Drugs. Biosensors 2019, 9, 45 .

AMA Style

Patrick Kobina Arthur, Anthony Boadi Yeboah, Ibrahim Issah, Srinivasan Balapangu, Samuel K. Kwofie, Bernard O. Asimeng, E. Johan Foster, Elvis K. Tiburu. Electrochemical Response of Saccharomyces cerevisiae Corresponds to Cell Viability upon Exposure to Dioclea reflexa Seed Extracts and Antifungal Drugs. Biosensors. 2019; 9 (1):45.

Chicago/Turabian Style

Patrick Kobina Arthur; Anthony Boadi Yeboah; Ibrahim Issah; Srinivasan Balapangu; Samuel K. Kwofie; Bernard O. Asimeng; E. Johan Foster; Elvis K. Tiburu. 2019. "Electrochemical Response of Saccharomyces cerevisiae Corresponds to Cell Viability upon Exposure to Dioclea reflexa Seed Extracts and Antifungal Drugs." Biosensors 9, no. 1: 45.

Review
Published: 10 January 2019 in Current Topics in Medicinal Chemistry
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Malaria is a major global health concern with the majority of cases reported in regions of South-East Asia, Eastern Mediterranean, Western Pacific, the Americas, and Sub-Saharan Africa. The World Health Organization (WHO) estimated 216 million worldwide reported cases of malaria in 2016. It is an infection of the red blood cells by parasites of the genus Plasmodium with most severe and common forms caused by Plasmodium falciparum (P. falciparum or Pf) and Plasmodium vivax (P. vivax or Pv). Emerging parasite resistance to available antimalarial drugs poses great challenges to treatment. Currently, the first line of defense includes artemisinin combination therapies (ACTs), increasingly becoming less effective and challenging to combat new occurrences of drug-resistant parasites. This necessitates the urgent need for novel antimalarials that target new molecular pathways with a different mechanism of action from the traditional antimalarials. Several new inhibitors and potential drug targets of the parasites have been reported over the years. This review focuses on the malarial aspartic proteases known as plasmepsins (Plms) as novel drug targets and antimalarials targeting Plms. It further discusses inhibitors of hemoglobin-degrading plasmepsins Plm I, Plm II, Plm IV and Histo-aspartic proteases (HAP), as well as HIV protease inhibitors of plasmepsins.

ACS Style

Whelton A. Miller Iii; Joshua Teye; Angela O. Achieng; Reagan M. Mogire; Hoseah Akala; John M. Ong'echa; Brijesh Rathi; Ravi Durvasula; Prakasha Kempaiah; Samuel K. Kwofie; Whelton Miller; John M. Ong`cha. Antimalarials: Review of Plasmepsins as Drug Targets and HIV Protease Inhibitors Interactions. Current Topics in Medicinal Chemistry 2019, 18, 2022 -2028.

AMA Style

Whelton A. Miller Iii, Joshua Teye, Angela O. Achieng, Reagan M. Mogire, Hoseah Akala, John M. Ong'echa, Brijesh Rathi, Ravi Durvasula, Prakasha Kempaiah, Samuel K. Kwofie, Whelton Miller, John M. Ong`cha. Antimalarials: Review of Plasmepsins as Drug Targets and HIV Protease Inhibitors Interactions. Current Topics in Medicinal Chemistry. 2019; 18 (23):2022-2028.

Chicago/Turabian Style

Whelton A. Miller Iii; Joshua Teye; Angela O. Achieng; Reagan M. Mogire; Hoseah Akala; John M. Ong'echa; Brijesh Rathi; Ravi Durvasula; Prakasha Kempaiah; Samuel K. Kwofie; Whelton Miller; John M. Ong`cha. 2019. "Antimalarials: Review of Plasmepsins as Drug Targets and HIV Protease Inhibitors Interactions." Current Topics in Medicinal Chemistry 18, no. 23: 2022-2028.

Journal article
Published: 27 June 2018 in Molecules
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Buruli ulcer (BU) is caused by Mycobacterium ulcerans and is predominant in both tropical and subtropical regions. The neglected debilitating disease is characterized by chronic necrotizing skin lesions attributed to a mycolactone, which is a macrolide toxin secreted by M. ulcerans. The preferred treatment is surgical excision of the lesions followed by a prolonged combination antibiotic therapy using existing drugs such as rifampicin and streptomycin or clarithromycin. These antibiotics appear not to be adequately potent and efficacious against persistent and late stage ulcers. In addition, emerging drug resistance to treatment poses great challenges. There is a need to identify novel natural product-derived lead compounds, which are potent and efficacious for the treatment of Buruli ulcer. Natural products present a rich diversity of chemical compounds with proven activity against various infectious diseases, and therefore, are considered in this study. This study sought to computationally predict natural product-derived lead compounds with the potential to be developed further into potent drugs with better therapeutic efficacy than the existing anti-buruli ulcer compounds. The three-dimensional (3D) structure of Isocitrate lyase (ICL) of Mycobacterium ulcerans was generated using homology modeling and was further scrutinized with molecular dynamics simulations. A library consisting of 885 compounds retrieved from the AfroDb database was virtually screened against the validated ICL model using AutoDock Vina. AfroDb is a compendium of “drug-like” and structurally diverse 3D structures of natural products originating from different geographical regions in Africa. The molecular docking with the ICL model was validated by computing a Receiver Operating Characteristic (ROC) curve with a reasonably good Area Under the Curve (AUC) value of 0.89375. Twenty hit compounds, which docked firmly within the active site pocket of the ICL receptor, were assessed via in silico bioactivity and pharmacological profiling. The three compounds, which emerged as potential novel leads, comprise ZINC38143792 (Euscaphic acid), ZINC95485880, and ZINC95486305 with reasonable binding energies (high affinity) of −8.6, −8.6, and −8.8 kcal/mol, respectively. Euscaphic acid has been reported to show minimal inhibition against a drug-sensitive strain of M. tuberculosis. The other two leads were both predicted to possess dermatological activity while one was antibacterial. The leads have shown promising results pertaining to efficacy, toxicity, pharmacokinetic, and safety. These leads can be experimentally characterized to assess their anti-mycobacterial activity and their scaffolds may serve as rich skeletons for developing anti-buruli ulcer drugs.

ACS Style

Samuel K. Kwofie; Bismark Dankwa; Emmanuel A. Odame; Francis E. Agamah; Lady P. A. Doe; Joshua Teye; Odame Agyapong; Whelton A. Miller; Lydia Mosi; Michael D. Wilson. In Silico Screening of Isocitrate Lyase for Novel Anti-Buruli Ulcer Natural Products Originating from Africa. Molecules 2018, 23, 1550 .

AMA Style

Samuel K. Kwofie, Bismark Dankwa, Emmanuel A. Odame, Francis E. Agamah, Lady P. A. Doe, Joshua Teye, Odame Agyapong, Whelton A. Miller, Lydia Mosi, Michael D. Wilson. In Silico Screening of Isocitrate Lyase for Novel Anti-Buruli Ulcer Natural Products Originating from Africa. Molecules. 2018; 23 (7):1550.

Chicago/Turabian Style

Samuel K. Kwofie; Bismark Dankwa; Emmanuel A. Odame; Francis E. Agamah; Lady P. A. Doe; Joshua Teye; Odame Agyapong; Whelton A. Miller; Lydia Mosi; Michael D. Wilson. 2018. "In Silico Screening of Isocitrate Lyase for Novel Anti-Buruli Ulcer Natural Products Originating from Africa." Molecules 23, no. 7: 1550.

Journal article
Published: 24 April 2018 in Polymers
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The sol-gel and cross-linking processes have been used by researchers to synthesize silica-based nanostructures and optimize their size and morphology by changing either the material or the synthesis conditions. However, the influence of the silica nanostructures on the overall physicochemical and mechanistic properties of organic biopolymers such as chitosan has received limited attention. The present study used a one-step synthetic method to obtain chitosan composites to monitor the uptake and release of a basic cationic dye (methylene blue) at two different pH values. Firstly, the composites were synthesized and characterized by Fourier Transform Infrared Spectroscopy (FTIR) and X-ray Diffraction (XRD) to ascertain their chemical identity. Adsorption studies were conducted suing methylene blue and these studies revealed that Acetic Acid-Chitosan (AA-CHI), Tetraethylorthosilicate-Chitosan (TEOS-CHI), Acetic Acid-Tetraethylorthosilicate-Chitosan (AA-TEOS-CHI), and Acetic Acid-Chitosan-Tetraethylorthosilicate (AA-CHI-TEOS) had comparatively lower percentage adsorbances in acidic media after 40 h, with AA-CHI adsorbing most of the methylene blue dye. In contrast, these materials recorded higher percentage adsorbances of methylene blue in the basic media. The release profiles of these composites were fitted with an exponential model. The R-squared values obtained indicated that the AA-CHI at pH ~ 2.6 and AA-TEOS-CHI at pH ~ 7.2 of methylene blue had steady and consistent release profiles. The release mechanisms were analyzed using Korsmeyer-Peppas and Hixson-Crowell models. It was deduced that the release profiles of the majority of the synthesized chitosan beads were influenced by the conformational or surface area changes of the methylene blue. This was justified by the higher correlation coefficient or Pearson’s R values (R ≥ 0.5) computed from the Hixson-Crowell model. The results from this study showed that two of the novel materials comprising acetic acid-chitosan and a combination of equimolar ratios of acetic acid-TEOS-chitosan could be useful pH-sensitive probes for various biomedical applications, whereas the other materials involving the two-step synthesis could be found useful in environmental remediation of toxic materials.

ACS Style

Thomas Y. A. Essel; Albert Koomson; Marie-Pearl O. Seniagya; Grace P. Cobbold; Samuel K. Kwofie; Bernard O. Asimeng; Patrick K. Arthur; Gordon Awandare; Elvis K. Tiburu. Chitosan Composites Synthesized Using Acetic Acid and Tetraethylorthosilicate Respond Differently to Methylene Blue Adsorption. Polymers 2018, 10, 466 .

AMA Style

Thomas Y. A. Essel, Albert Koomson, Marie-Pearl O. Seniagya, Grace P. Cobbold, Samuel K. Kwofie, Bernard O. Asimeng, Patrick K. Arthur, Gordon Awandare, Elvis K. Tiburu. Chitosan Composites Synthesized Using Acetic Acid and Tetraethylorthosilicate Respond Differently to Methylene Blue Adsorption. Polymers. 2018; 10 (5):466.

Chicago/Turabian Style

Thomas Y. A. Essel; Albert Koomson; Marie-Pearl O. Seniagya; Grace P. Cobbold; Samuel K. Kwofie; Bernard O. Asimeng; Patrick K. Arthur; Gordon Awandare; Elvis K. Tiburu. 2018. "Chitosan Composites Synthesized Using Acetic Acid and Tetraethylorthosilicate Respond Differently to Methylene Blue Adsorption." Polymers 10, no. 5: 466.