Pusat Pengajian Sains Kimia - Tesis

Browse

Now showing 1 - 20 of 102

Anti-Diabetic Activity Of Chemical Constituents Isolated From Kopsia Teoi And Catharanthus Roseus (Apocynaceae), And Corrosion Inhibition Studies Of Its Extracts
(2025-05)
Jaf, Muhammad Tahir Muhammad Al
This research involved extracting dried ground bark from kopsia teoi (k. Teoi) and catharanthus roseus (c. Roseus) using n-hexane, dichloromethane (dcm), and methanol (meoh) solvents to produce the crude extracts. Alkaloids were isolated from dragendorff-positive dcm extracts via acid-base extraction with hcl and nh4oh, yielding a dcm alkaloid extract. Fractionation by cc and analysis by tlc led to further purification, isolating alkaloids. From k. Teoi, ten compounds were isolated, including four new compounds: 16-epi-deacetylakuammiline n(4)-methylene chloride (602), n(1)-methoxycarbonyl-11-methoxy-12-hydroxy-δ14‒17-kopsinine (603), n(1)-methoxycarbonyl-11,12-methylenedioxy-δ14‒17-kopsinine (604), and n(4)-hydroxymethyl-kopsinine (605). Additionally, known compounds were isolated, including leuconolam (301), kopsiloscine g (413), e-akuammidine (132), n(1)-methoxycarbonyl-12-methoxy-δ16,17-kopsinine (302), kopsininate (312), and n(1)-methoxycarbonyl-11,12-methylenedioxy-δ16,17-kopsinine (383). Meanwhile, from c. Roseus, five compounds were isolated, including one new compound: 16-epi-deacetylakuammiline-7-methyl-n(4)-methylene chloride (606), and four known compounds, namely: β-amyrin (590), ursolic acid (591), dodecanoic acid (596), and oleic acid (598). The isolated compounds were characterised using ft-ir (atr), 1d- and 2d- nmr, uv spectroscopy, and high-resolution electrospray ionisation mass spectroscopy (hresims), with comparison to literatures data.
Binary And Ternary Complexes Of Β-Cyclodextrin With Isoniazid And Ethambutol: Characterization And Molecular Modeling Studies
(2023-09)
Goh, Soen Qeng
Long term intake of antituberculosis drugs will lead to severe adverse reactions that will ultimately deteriorate a patient’s health and well-being. Presently, it is known that supramolecular macrocycles such as cyclodextrins (CDs) are useful to enhance drug solubility and targeting mechanism while reducing drug dosage by providing many therapeutic benefits. With that, the possibility of formation of drug-CDs ternary inclusion complex was explored, whereby β-cyclodextrin (β-CD) was chosen as the supramolecular host carrier to accommodate two kinds of first-line antituberculosis guest drug molecules simultaneously, namely isoniazid (INH) and ethambutol (ETB). The inclusion complex of β-CD/INH/ETB was prepared using solvent evaporation method. Fourier transform infrared spectroscopy (FT-IR), proton nuclear magnetic resonance spectroscopy (1H-NMR), and 2-dimensional nuclear Overhauser effect spectroscopy (2D-NOESY) NMR were used to investigate the functional groups and structure of the complex. Scanning electron microscopy (SEM) and X-ray diffraction (XRD) were employed to study the surface morphology and crystallinity changes during complex formation. Thermogravimetric analysis (TGA) was performed to investigate the thermal properties of the complex. FT-IR and both types of NMR results had revealed the successful penetration of both the drug molecules into the β- CD cavity. SEM images and XRD spectra had shown a drastic change in surface structure and reduction in crystallinity during complex formation, which had indicated successful formation of a new compound.
Bio-Based Graphene From The Oil Palm Empty Fruit Bunches As A Fluid Loss Additive In The Water-Based Drilling Mud
(2024-04)
Safian, Muhammad Taqi-Uddeen
One of the most serious issues encountered during drilling operations is the loss of drilling fluid through the well formation, which is referred to as fluid loss, resulting in dry drilling fluid and increasing the likelihood of the drill being stuck. To prevent this scenario, a fluid loss additive was added to the drilling mud. The effectiveness of bio-based graphene (BG) prepared from oil palm (Elaeis guineensis) empty fruit bunches biomass as a fluid loss additive for water-based drilling mud (WBM) was investigated. To accomplish this, BG was exfoliated from lignin extracted through a soda pulping process. The BG exfoliation process consisted of a combination of thermal treatment via pyrolysis at 300, 600, 800, and 1000 °C with a reaction time of 60 minutes under an argon atmosphere, followed by a mechanical exfoliation using a homogenizer with a shear rate of 12400 rpm for 1 hour. Ultraviolet-visible spectroscopy (UV-Vis), thermogravimetric analysis (TGA), Fourier-transform infrared spectroscopy (FTIR), Raman spectroscopy, transmission electron microscopy (TEM), scanning electron microscopy (SEM), atomic force microscopy (AFM), and x-ray photoelectron spectroscopy (XPS) were used to characterize each prepared sample. The Raman analysis confirmed the graphene formation based on the I2D/IG value similar to the commercial graphene, i.e., 0.91. The FTIR analysis revealed that the BG structure has a less functional group than GO, which has been confirmed using XPS as the C/O ratio of BG is less than GO.
Bioassay-Guided Isolation, Characterisation And Molecular Docking Study Of Acetylcholinesterase And Butyrylcholinesterase Inhibitors From Horsfieldia Polyspherula And Horsfieldia Tomentosa
(2025-01)
Mohammed, Idriss
Alzheimer’s disease (ad) is a neurodegenerative disorder associated with ageing. It is characterised by beta-amyloid deposition, aggregation of neurofibrillary tangles, oxidative stress and decreased acetylcholine levels. Horsfieldia species, known for their medicinal properties, have yielded secondary metabolites with various health benefits. This research highlighted the emergence of various secondary metabolites coupled with a considerable amount of phenolic and flavonoid constituents in the extracts of h. Polyspherula and h. Tomentosa. A total of seventeen unique compounds were isolated, ten of which were from the ethyl acetate (etoac) extract of the bark of h. Polyspherula, while another seven from the etoac extract of h. Tomentosa fruit. Hence, the isolated compounds from h. Polyspherula are; 3,4-dihydroxybenzoic acid (85), 16-phenylhexadecanoic acid (86), undecylbenzene (87), lauric acid (88), myristic acid (89), pentadecanoic acid (90), 1-tridecene (91), trimyristin (92), δ-tocotrienol (93) and stigmasterol (94). Meanwhile, for h. Tomentosa, the isolated compounds include trimyristin (92), (-)-sesamin (95), 1-(2,4,6-trihydroxyphenyl)decan-1-one (96), 1-(2,4,6-trihydroxyphenyl)-12-phenyl-dodecan-one (97), 1-(2,6-dihydroxy-4-(octylo-xy)phenyl)-11-undecan-1-one (98), 9-octyl-sesamin (99) and methyl myristate (100), three of which 97-99 are new.
Bis-, Tris-, And Tetrakisbenzimidazolium Salts And Their Silver(I) Complexes: Synthesis, Characterization And Biological Applications
(2024-09)
Abdurrahman, Nuraddeen
This research describes the synthesis, characterization, crystal structure and cytotoxicity activity of several new bis-, tris- and tetrakis-benzimidazolium salts, (1- 24) and their respective silver(I)-benzimidazol-2-ylidene complexes, (Ag1-Ag24). All the compounds synthesized were new based on literature reviewed, it was achieved by changing the either the alkyl or aryl substituents on the benzimidazolium systems and or the bridging ligands related to the previously reported compounds. The salts were synthesized by nucleophilic substitution reaction and were categorized into five series. The salts were 1-5, 6-9, 10-14, 15-19, 20-24 as first, second, third, fourth and fifth series respectively. The synthesized salts were utilized for the synthesis of their respective silver(I)-benzimidazol-2-ylidene complexes, by in-situ deprotonation method in the presence of silver(I)oxide. The cytotoxicity potential of the synthesized compounds was carried out by MTT assay method, in which the breast and cervical cancer cell lines were used. Salt 1-5, 6-9, 15-19, and their silver(I)-benzimidazol-2-ylidene complexes, (Ag1-Ag5, Ag6 -Ag9, Ag15-Ag19) were tested against breast cancer cell lines, while salts, 10-14, 20-24, and their silver(I)-benzimidazol-2-ylidene complexes, (Ag10-Ag14, Ag20-Ag24) were tested against cervical cancer cell lines. The positive control used for the breast cancer cell was tamoxifen and etoposide for the cervical cancer cell. All the salts and their respective silver(I)-benzimidazol-2-ylidene complexes synthesized were characterized using various characterization techniques including FTIR, 1H, 13C NMR, elemental analysis, and single crystal X-ray diffraction method. Physical properties were accessed by melting point analysis, and solubility tests in various organic solvents. From structural elucidation, it was confirmed that Ag2 was dinuclear silver(I)-benzimidazol-2-ylidene complex, with two PF6 anions as counterions balancing the charges of the entire molecule. Complex Ag13 confirmed to be a cylinder-like trinuclear silver(I)-benzimidazol-2-ylidene complex containing three silver(I) ions bridged by two disc-like ligands.
Catalytic Dehydrogenation Of Hydrazine Borane Over Cu@Ni/Moo3 Core Shell Catalyst For Hydrogen Storage Application
(2025-08)
Lei, Yunfeng
Hydrogen energy is a promising clean energy source, and efficient hydrogen storage remains a critical challenge. Hydrazine borane (N2H4BH3, HB), with a high hydrogen content of 15.4 wt%, has attracted attention as a potential chemical hydrogen storage material. However, conventional methanolysis reactions typically utilize only the BH3 moiety, limiting hydrogen release. In this study, we developed a highly efficient MoO3-supported copper–nickel core–shell catalyst (Cu@Ni/MoO3) to enable complete hydrogen release from both the BH3 and N2H4 moieties. At 50 °C, the system achieved a yield of 5.5 moles of gas, the highest reported for HB methanolysis under mild conditions. Kinetic studies showed a low activation energy of 36.5 ± 3.5 kJ/mol for the second dehydrogenation step, indicating rapid hydrogen evolution at relatively low temperatures.
Characterization, Kinetics And Equilibrium Studies Of Paracetamol Adsorption On The Oil Palm Fronds (Opf) Cellulose Nanocrystals
(2022-02)
Idris, Nor Najhan
Pollution of water via pharmaceutical drugs such as paracetamol have been a highly concerning issue; and effective measures must be taken to treat these aquatic contaminants. Hence, the present study explored use of cellulose nanocrystals (CNC) isolated from oil palm fronds (OPF) through pre-treatments and acid hydrolysis as an environmental friendly adsorbent. The complementary analyses showed that the OPF CNC possesses a crystallinity index of 43.60 %, surface area (10.51 m2 g-1), and an aspect ratio of 19.98. Besides, the OPF CNC and OPF CNC-AC hydrogel beads have been successfully produced, optimised, and applied for paracetamol removal. The modification of OPF CNC-AC hydrogel beads with the commercial activated carbon (AC) has improved the BET surface area up to 85.19 m2 g-1. The adsorption studies of paracetamol onto OPF CNC and OPF CNC-AC hydrogel beads can be achieved at 60 g and 0.6 g of adsorbent dosage, respectively, at a pH 3 with a contact time of 170 min under room temperature. It was observed that the produced data fitted best with the pseudo-second order kinetic model and Freundlich isotherm model for characterising the adsorption of paracetamol onto OPF CNC hydrogel beads with a maximum adsorption capacity, qmax of 0.03 mg g-1. Meanwhile, for OPF CNC-AC hydrogel beads, the pseudo-second order kinetic model and Langmuir isotherm model showed the best correlation for the adsorption of paracetamol with a qmax value of 21.31 mg g-1. Therefore, the output from this study may suggest that OPF CNC and OPF CNC- xxiv AC hydrogel beads can be used as natural adsorbents for the removal of paracetamol waste.
Chemical Characterisation, Enantioselective Profiling And Bioactivites Of Malaysian Citrus Spp. Leaf Extracts
(2025-08)
Al Othman, Haneen Ibrahim Ahmad
Authentication and quality control of Citrus essential oils remain challenging due to their complex chemical composition, the presence of trace adulterants, and the lack of robust analytical methodologies. While Citrus-derived peel essential oils are widely recognized for their therapeutic and medicinal applications, systematic characterization of leaf-derived Citrus spp. essential oils rand their bioactivity remains underexplored. This study examined the volatile constituents of essential oil distilled from the leaves of Malaysian C. hystrix, C. limon, C. pyriformis, and C. microcarpa, using gas chromatography–quadrupole mass spectrometry. Additionally, headspace solid-phase microextraction (HS-SPME) was used to profile the biogenic volatile organic compounds emitted from the freshly collected leaves of these four Citrus spp. to allow near-real-time measurement of leaf volatiles without physicochemical stress.
Comparative Analysis Of The Bioethanol Yield And Components Of Sugar Extracted From Oil Palm Frond Under Different Prehydrolysis Treatments
(2021-11)
Dissanayake Mudiyanselage Rushan Lakshitha Bonuwan Diyanilla
this study was designed to produce a high bioethanol yield from OPF adopting eco-friendly and viable pretreatment methods, which are acid, autohydrolysis, alkaline, alkaline peroxide, and alkaline peroxide pretreatment coupled with acidified sodium chlorite (ASC) pretreatment
Computational Design And Investigation Of New Benzophenones And Benzophenone Imines Inhibitors For Breast Cancer
(2018-10)
Shtaiwi, Amneh Mohammad
The computational methods of protein-ligand interactions are core components in drug design and modem drug discovery. This study attempted to design and investigate the interactions of new human estrogen receptor (hERa) inhibitors to treat breast cancer cells using molecular modeling approach. The proposed inhibitors were designed by replacing the triarylethylene estrogenic scaffold found in the synthetic inhibitor 4-hydroxytamoxifen (4-0HT) with triarylimine Schiff bases.
Crystallization Study Of Silicoaluminophosphate Zeolites Templated Using Pyridinium Cations And Their Catalytic Behaviors In Esterification Reactions
(2025-06)
Mohammad, Al Issa Jehad Mohdfathi
This thesis presents three interconnected studies on the crystallization of SAPO zeolites. The first study investigates the crystallization of SAPO-11 under ionothermal conditions using 1-propylpyridinium bromide ([PPy]Br) as template. The effects of synthesis parameters are studied, and SAPO-11 with an acidic nature and high surface area is successfully synthesized after 133 h of heating at 150 °C. The second study explores the crystallization of SAPO-5 under hydrothermal conditions using 5-ethyl-2-methyl-1-propylpyridinium hydroxide ([empy]OH) new template, where H3PO4 and H4P2O7 are used as comparative P sources. Both crystallization processes are followed, and the effects of these P sources on the crystallization and structural properties of SAPO-5 are examined. The findings reveal that H3PO4 yields highly crystalline hierarchical SAPO-5 with high acidity, whereas H4P2O7 promotes nucleation, forming SAPO-5 nanoplates with textural mesoporosity. The third component focuses on the catalytic performance of synthesized SAPO zeolites.
Cycloketone And Coumarin-Based Chalcone And Pyrazoline Derivatives: Synthesis, In Silico Studies, Antioxidant And Cytotoxic Activities Against Mcf-7 Cell Line
(2025-06)
Sadiq, Abubakar
This study focuses on the synthesis, characterisation, in silico study and biological evaluation of cycloketone and coumarin-based chalcone and pyrazoline compounds, as potential antioxidant and anticancer agents. All these compounds were successfully synthesised through claisen-schmidt condensation and subsequent cyclo-condensation reaction. The structure of the compounds was confirmed using various spectroscopic techniques, including ftir and nmr. The molecular docking study was performed to predict the binding affinity of the synthesised compounds towards the target estrogen receptor alpha erα (3ert) protein involved in breast cancer pathways. The potential interactions suggest the effective binding of these compounds to the key amino acids associated with erα. The antioxidant activity of the compounds was evaluated using the dpph (2,2-diphenyl-1-picrylhydrazyl) radical scavenging assay, which serves as a preliminary screening method to identify potential free radical inhibitors. Compounds 2c (ic50 = 20.49 μm) and 3c (ic50 = 24.49 μm) showed a slightly better activity than trolox (ic50 = 30.83 μm), suggesting their potential as effective radical scavengers. Pyrazoline compounds in series 1 such as 1civ and 1div showed good antioxidant activity of ic50 29.70 and 20.74 μm, respectively, while pyrazoline compounds in series 2 namely 2di, 2dii and 2div showed the ic50 of 26.93, 27.49 and 24.68 μm, respectively.
Cytotoxic Activity Of Isolated Alkaloids From The Bark Of Kopsia Terengganensis (Apocynaceae) And Corrosion Inhibition Studies Of Its Extract
(2023-09)
Hanafi, Wan Nur Huda Wan
The use of natural products in developing chemotherapy agents has shown a positive impact in the oncology field. Besides, they also showed a significant result as a corrosion inhibitor. Hence, this study aims to evaluate the cytotoxic activity and corrosion inhibition potential of the crude extract and isolated alkaloids from Kopsia terengganensis (K. terengganensis). The experimental involved extraction and isolation of alkaloids using different chromatographic methods, structural elucidation using various chromatographic techniques and evaluation of cytotoxic activity on HT-29 colorectal adenocarcinoma. Meanwhile, corrosion inhibition studies included weight loss studies, electrochemical studies, and surface analysis. The extraction and isolation process resulted in seven alkaloid compounds: eburnamine (90), isoeburnamine (58), eburnaminol (99), larutensine (100), eburnamenine (114), eburnamonine (56) and quebrachamine (148). In the cytotoxic activity, only compound 99 was able to suppress the growth of HT-29 with moderate activity (IC50 =75.8± 3.06 μM). For the corrosion inhibition potential, the alkaloid crude showed significant results (80-90% inhibition efficiency) in both weight loss and electrochemical studies. The inhibitor followed the Langmuir adsorption isotherm and the formation of an inhibitive film on the mild steel surface was proved in the surface analysis. In conclusion, the alkaloids from K. terengganensis were noteworthy to be investigated in both cancer and corrosion inhibition studies as it gives a positive result in the toxicity towards cancer cells and also mitigated the mild steel corrosion.
Design, Synthesis, Biological Evaluation, And Molecular Docking Studies Of Ortho-Carboxamido Stilbenes As Anti-Diabetic And Anti-Proliferative Agents
(2022-09)
Norhadi Bin Mohamad
A total of eleven ortho-carboxamido stilbenes (50a-50k) in 63-83 % yield have been synthesized using our modified Heck coupling method, and characterized using FT-IR, NMR, and HRMS. The research started with the Wittig reaction of 3,5-dimethoxybenzaldehyde (45) and methyltriphenylphosphonium iodide to form 3,5-dimethoxystyrene (46) followed by the Heck reaction with amide derivatives (49) under basic conditions to provide the corresponding (E)-stilbene derivatives (50a-50k). Five ortho-carboxamido stilbenes (50a-50e) were subjected to anti-diabetic studies on α-amylase and α-glucosidase enzymes.
Design, Synthesis, Molecular Docking And Cytotoxic Activity Of New Ortho-Hydroxy Chalcone And Pyrazoline Derivatives
(2019-06)
Luhaibi, Maadh Jumaah Owaid
This study focused on the design and synthesis of new compounds with anticancer activity. The compounds were constructed using the structure-based drug design, focusing on their binding capabilities to the Colchicine (PDB code: IS AO) active site in a bidentate manner, with the most energetically preferable binding modes using Autodock Vina 1.1.2 and Discovery studio 4.1. In the molecular docking analysis, the binding energy and interactions between protein receptors and ligands provide a better understanding of the biological functions to determine the amino acid residues which are crucial to docking interactions. The modification and replacement of the pyrazoline structure and chaicone led to the development of the structureactivity relationship and identified potent and selective inhibitors of drug design.
Development Of An Electrochemical Sensor Based On Molecularly Imprinted Go/Zno/Ppy Composites On Pencil Graphite Electrode For Determination Of Andrographolide
(2021-12)
Rabia Tasaduq Hussain
This research highlights the development of an electrochemical sensor based on graphene derivatives with a molecularly imprinted polypyyrole (PPy) layer on a pencil graphite electrode (PGE) to detect andrographolide, which is a bioactive component of an ancient plant known as Andrographis paniculata. Conventionally, andrographolide detection based on tedious and heavy instrumentation.
Development Of Extraction And Separation Techniques For The Determination Of Fatty Acids And Phenolic Compounds In Stingless Bee And Tualang Honey
(2025-09)
Al Wade, Anass
Malaysian stingless bee honey (SBH) and Tualang honey (TH), have garnered increasing interest for their distinctive composition and pharmacological benefits. However, the accurate quantification of phenolic compounds (PCs) and fatty acids (FAs) in honey remains a significant analytical challenge due to their structural variability and sugar-rich honey matrix interference. Existing methods often lack the sensitivity, selectivity, and environmental sustainability required for modern analyses. This thesis addresses these limitations by developing and validating sample preparation methods with advanced separation techniques for the determination of PCs and FAs in SBH, TH and Apis mellifera honey.
Development Of Extraction And Separation Techniques For The Determination Of Polycyclic Aromatic Hydrocarbons And Biogenic Amines In Food
(2024-01)
Hor, Jia Yi
Polycyclic aromatic hydrocarbons (PAHs) and biogenic amines (BAs) are potential contaminants in various food products. Quantitative analysis of these contaminants in food is challenging due to their high physicochemical variability and complexity. This thesis describes the method developments for quantitative analysis of PAHs and BAs in selected food products.
Development Of Fatty Acid-Based Deep Eutectic Solvents In Liquid Phase Microextraction With Back Extraction For Determination Of Selected Organic Pollutants
(2024-04)
Sazali, Nur Hidayah
Environmental pollution has become a significant global issue in recent times. The primary sources of this pollution are human activities such as industrial processes, marine dumping, agricultural practices, and wastewater discharges. Some of the most concerning environmental pollutants are pesticides, herbicides, and polycyclic aromatic hydrocarbons (PAHs) due to their high toxicity and their persistence in the environment. These pollutants have harmful effects on human health and the ecosystem. Due to their high toxicity and trace amount in environment, developing an effective extraction method is essential. Deep eutectic solvent (DES) is a possible green alternative to the conventional solvent utilised in most extraction procedures in light of the increased demand for developing green extraction techniques. Microextraction-based DES fits favourably with the Green Analytical Chemistry (GAC) concept because of its rapid sample preparation time, low organic solvent usage, and straightforward procedure. In this study, an eco-friendly microextraction utilising hydrophobic deep eutectic solvents from fatty acids derived from the combination of lauric acid, which acted as a hydrogen bond acceptor (HBA), and pelargonic acid, which acted as a hydrogen bond donor (HBD), was prepared to determine herbicide mixtures using emulsification liquid-liquid microextraction with back extraction (ELLME-BE) method. In addition, a ferrofluid was developed by incorporating DES, a combination of lauric acid (HBA) and caprylic acid (HBD) with magnetic nanoparticles (MNP) to determine polycyclic aromatic hydrocarbons xxviii (PAHs) using liquid phase microextraction with back extraction (LPME-BE) method. Fourier transform infrared spectroscopy (FTIR), thermogravimetric analysis (TGA),
Development Of Magnetic Graphene Oxide-Deep Eutectic Solvent Based Ferrofluids For The Determination Of Selected Organophosphorus Pesticides In Water Samples
(2025-09)
Hamad, Alghodran Musab Ahmad
The widespread use of OPPs in agriculture has led to their persistence in aquatic environments, posing serious ecological and health concerns. Detecting organophosphorus pesticides (OPPs) at trace levels remains challenging due to matrix interferences and low concentrations, which necessitate the development of rapid, sensitive, and eco-friendly analytical methods. Therefore, this study aimed to develop and characterize MGO-DES FF, optimize its use in LPME, evaluate its adsorption behaviour, and validate its application for real water samples. In this study, a smart ferrofluid (FF) was developed for the extraction of OPPs. The FF was synthesized by incorporating magnetic graphene oxide (MGO) as a magnetic nanocomposite and a deep eutectic solvent (DES) as the carrier medium. The synthesized material was characterized using FTIR, TEM, SEM, XRD, TGA, and VSM. The adsorption performance of methidathion (MET), malathion (MAL), quinalphos (QUI) and diazinon (DIZ) was evaluated through kinetic, isotherm, and thermodynamic models.

Browse

Browsing Pusat Pengajian Sains Kimia - Tesis by Title

Results Per Page

Sort Options