Theses (MSc in Analytical and Pharmaceutical Chemistry)

Labdane diterpenoids are phytochemicals which have been reported effectively against acetylcholinesterase inhibition. Butyrylcholinesterase is another enzyme involved in hydrolysis of acetylcholine in the brain. Both enzymes are regarded as important therapeutic target for Alzheimer’s disease. Nonetheless, study on the effect of labdane diterpenoids towards butyrylcholinesterase inhibition is scarce. This project aimed to study the pharmacokinetic profiles of labdane diterpenoids of Alpinia genus via in silico methods and to evaluate their binding interactions in the active site of butyrylcholinesterase through molecular docking. A series of thirty labdane diterpenoids from Alpinia genus were investigated for their physicochemical properties using Molinspiration server and the pharmacokinetics profiles using pkCSM. Docking systems consisting of butyrylcholinesterase protein (PDB ID: 4BDS) and labdane diterpenoids were subjected to docking studies using AutoDockTools. Protein-Ligand Interaction Profiler was used to analyse the docking outputs; LigPlot Plus was used to illustrate the binding interactions between butyrylcholinesterase protein and labdane diterpenoids. A total of twenty labdane diterpenoids met the requirement of Lipinski’s rule and complied to Veber rule. Several labdane diterpenoids in the present study have exhibited drug likeness, good oral bioavailability as well as considerable drug distribution and blood-brain-barrier penetration based on in silico prediction. All compounds were shown to have relatively good binding within the binding site of butyrylcholinesterase from the docking studies in comparison to the co-crystallised ligand, tacrine based on the binding energy; their binding energies ranged from -17.70 kcal/mol to -7.3 kcal/mol versus that of tacrine with binding energy of -7.71 kcal/mol. Hydrogen bonding and hydrophobic interactions were found as the main binding interactions between the binding site residues and labdane diterpenoids. Amongst the compounds, ligand no. 1 showed the highest binding energy of -16.00 kcal/mol and the lowest estimated Ki of 1.86 pM. In conclusion, several labdane diterpenoids in the present study have demonstrated good pharmacokinetic profiles based on the in silico prediction. These compounds were also shown to have relatively good binding within the binding site of butyrylcholinesterase based on the molecular docking studies. Keywords: Labdane diterpenoids, butyrylcholinesterase, Alzheimer’s disease, pharmacokinetics, molecular docking

Tocotrienols (T3), a subfamily of vitamin E, are gaining recognition for their potent antioxidant, anti-inflammatory, and neuroprotective properties. However, their use in functional foods and medicinal products faces challenges such as low water solubility, instability under environmental conditions, and susceptibility to oxidative degradation. This study aims to address these challenges by using spray drying as an encapsulation technique to convert liquid nano emulsions of T3 into stable, dry powders. The process is guided by the Quality by Design (QbD) methodology, which optimises the spray drying parameters and the selection of wall materials to enhance the stability of nano-T3 powders. The results indicate that the combination of sodium caseinate and fibersol as wall materials effectively encapsulated T3, preserving its chemical integrity during processing. The optimised spray drying conditions produced nano-sized particles with ideal characteristics such as excellent flowability (10.71 ± 1.12%), wettability (93.07 ± 6.01%), low moisture content (1.79 ± 0.02%), particle size (100.42 ± 48.05 nm) and Vitamin E content (579.00 ± 233.39 mg/g). However, stability testing revealed that while the nano-T3 powder retained its chemical stability, moisture absorption over time led to particle aggregation and a decrease in T3 content. This indicates a need for further optimisation to improve moisture resistance and long-term stability. The study highlights the significant impact of wall materials and spray-drying parameters on the properties of nano-T3 powders and provides valuable insights into enhancing their stability and efficacy. Future research should focus on refining the encapsulation matrix and exploring the incorporation of antioxidants to mitigate degradation, thereby improving the stability and functional applications of nano-T3 in pharmaceuticals, nutraceuticals, and functional foods. In conclusion, this study demonstrates the potential of spray-dried nano-T3 as a stable, bioactive ingredient for diverse applications, with room for improvement in moisture resistance to enhance long-term stability.

The emergence and re-emergence of viral pathogens such as SARS-CoV-2, human immunodeficiency virus (HIV-1), hepatitis C virus (HCV), Zika virus (ZIKV), and dengue virus (DENV) continue to pose significant global health challenges. Viral proteases play a central role in viral replication through polyprotein processing and therefore represent attractive targets for antiviral drug development. This dissertation investigates the identification of synthetic viral protease inhibitors using an integrated in silico approach comprising Structure-Based Pharmacophore Modelling (SBPM), virtual screening, molecular docking, and pharmacokinetic prediction. High-resolution crystal structures of five disease-specific viral proteases (PDB IDs: 8HUR, 4WF8, 3SPK, 2FOM, and 5H4I) were analyzed to generate validated structure-based pharmacophore models using the Pharmit platform. These models were applied to virtually screen large compound libraries, including ZINC and MolPort, to identify molecules exhibiting key interaction features within protease active sites. The top-ranked virtual hits were further evaluated through molecular docking simulations using iGEMDOCK to predict binding conformations, interaction profiles, and relative binding affinities. Drug-likeness and ADMET properties were assessed using the SwissADME web tool. Several chemically diverse lead scaffolds, including triazine, indazole, and isoquinoline cores, demonstrated favorable hydrogen bonding, π–π stacking, and hydrophobic interactions with conserved catalytic residues across multiple viral proteases. Notably, some compounds exhibited multi-target binding potential, indicating suitability for broad-spectrum antiviral development. Overall, this study demonstrates that SBPM integrated with molecular docking provides an efficient and cost-effective computational framework for antiviral lead identification and establishes a strong foundation for future experimental validation and optimization. Keywords: viral proteases; structure-based drug design; pharmacophore modelling; virtual screening

Wound healing is a complex biological process requiring a coordinated response to restore damaged tissue. Traditional wound dressings such as gauze and bandages provide protection but lack bioactivity, delaying healing. In addition, drug-resistant bacteria are an ever-evolving issue that poses a problem. This limitation can lead to prolonged recovery times and increased susceptibility to infections. This study investigated sodium alginate-carboxymethyl cellulose composite hydrogels incorporating bioactive glass and alizarin for wound healing applications. Formulations made up of sodium alginate and sodium carboxymethyl cellulose, alizarin, and bioactive glass were prepared via lyophilisation. Fourier transform infrared spectroscopy confirmed the presence of sodium alginate, sodium carboxymethyl cellulose, alizarin, and bioactive glass and indicated successful incorporation of these components. Scanning electron microscopy explored the porosity of the samples and proved that alginate-carboxymethyl cellulose hydrogels have the most pores present to facilitate and house active components. Antioxidant assays showed alizarin’s dose-dependent radical scavenging activity. At the same time, drug-release studies indicated near-complete alizarin release within 168 hours. Degradation in PBS was slower in bioactive glass-rich formulations. Antibacterial studies against Staphylococcus aureus and Pseudomonas aeruginosa showed that samples with an equal ratio of bioactive glass and alizarin showed the highest reduction in the bacteria strains compared to the control. MTT assays indicated that alginate-carboxymethyl cellulose hydrogels and samples with bioactive glass only exhibited the highest number of living and healthy cells compared to alginate-carboxymethyl cellulose with alizarin incorporated. Finally, in scratch assays, the sample with equal alizarin and bioactive glass ratios displayed the most rapid wound closure, suggesting that a balance of components can significantly enhance wound healing. Overall, this study demonstrates that combining sodium alginate, sodium carboxymethyl cellulose, bioactive glass, and alizarin can produce hydrogels with promising antioxidant, antibacterial, and tissue-regenerative properties for wound-healing applications. However, further optimisation may be required to balance cytocompatibility and antibacterial efficacy.

Nanofibers have become a prominent research focus in wound dressing applications due to their exceptional material properties. The drug-loaded nanofibers can effectively eliminate the bacterial growth in the wound site. This study presents the formulation and fabrication of chitosan-gelatin (CS-GEL) nanofibers incorporated with curcumin and copper/zinc-based metal-organic framework (Cu/Zn-MOF) using the electrospinning method. The Cu/Zn-MOF was analysed using X-ray diffraction (XRD). The CS-GEL nanofibers loaded with curcumin and copper/zinc MOF were characterized with ATR-FTIR spectroscopy and scanning electron microscopy (SEM). The in-vitro antioxidant, anti-inflammatory, cytotoxicity, and antibacterial properties were also evaluated. The optimal conditions for smooth nanofiber production were identified as a polymer concentration of 3% (w/v) chitosan and 45% (w/v) gelatin, with a 30:70 chitosan-to-gelatin ratio. The optimized electrospinning parameters included an applied voltage of 18 kV, a flow rate of 0.8 mL/h, and a working distance of 15 cm. The optimized concentration of curcumin-Cu/Zn-MOF/CS-GEL nanofibers showed no toxic effects on HaCaT cells in 5% (w/v) of curcumin. Additionally, the 5CUR/10CuZn-MOF/CS-GEL nanofiber sample showed the highest percentage of DPPH radical scavenging (83.70%) for antioxidant activity. The highest percentage inhibition for the formulation of curcumin and MOF was 83.10%. The incorporation of curcumin and Cu/Zn-MOF effectively inhibited the growth of S. aureus and P. aeruginosa in antibacterial assays. The 5CUR/10CuZn-MOF/CS-GEL nanofiber sample was the most effective formulation against S. aureus and P. aeruginosa for antibacterial test. The 5CUR/10CuZn-MOF/CS-GEL nanofiber sample also showed the anti-biofilm effect against S. aureus. The 5CUR/1CuZn-MOF/CS-GEL, 5CUR/5CuZn-MOF/CS-GEL and 5CUR/10CuZn-MOF/CS-GEL nanofiber samples demonstrated potential applications for wound healing, as they were non-toxic to cells and exhibited antibacterial activity, which showed wound healing rate of 95.30%, 99.30% and 96.96%, respectively. The potential application of advanced wound dressings and nanotechnology lies in their ability to enhance healing rates and improve treatment outcomes.