Pusat Penyelidikan Biokimia Analisis - Tesis

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    Microwave-Assisted Extraction Of Polysaccharide From Cinnamomum Cassia With Anti-Hyperpigmentation Properties
    (2023-06)
    Al Ajalein Alhareth Abdulraheem Salem
    Polysaccharides with anti-hyperpigmentation properties have not been reported elsewhere. The current study extracted the polysaccharides from Cinnamomum cassia bark using microwave-assisted approach, and optimized the extraction parameters (i.e. microwave power, irradiation time and buffer-to-sample (B:S) ratio) based on Box-Behnken design to obtain polysaccharides with high anti-hyperpigmentation activities, antioxidant activity, sun protection factor (SPF) as well as the extraction yield.
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    Elucidation And Comparison Of Proteome Profiles In Normal, Precancerous And Cervical Cancer Tissues
    (2024-04)
    Gaayathri A/P Kumarasamy
    The aim of this study was to determine the protein profiles and differentially expressed proteins in the normal cervix, HPV-associated squamous intraepithelial lesion (SIL) which is precancerous and cervical cancer, extracted from formalin-fixed paraffin-embedded (FFPE) tissues.
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    Identification Of Bioactive Peptide From Chicken Ovalbumin Using An Integrated Bioinformatics-assisted Approach And Determining Their Functional Significance
    (Universiti Sains Malaysia., 2021-10)
    Mohd Adam Salim Mohd Salim
    complete integrated bioinformatics approach was developed to identify angiotensin-converting enzyme (ACE) and dipeptidyl peptidase-4 (DPP-4) inhibitory peptides from chicken ovalbumin (OVA). This approach involved PeptideCutter, Peptide Ranker and Pepsite2 in order to hydrolyse OVA protein sequence into smaller peptides, to identify the probability of the peptides being bioactive and to investigate the interaction between the peptides and target enzymes (i.e. ACE and DPP-4), respectively. OVA sequence was initially hydrolysed using PeptideCutter. Pepsin (P), Chymotrypsin (C) and Trypsin (T) were used in 7 different OVA (O) hydrolysis combination (OP, OC, OT, OCT, OPC, OPT and OPCT), thus, producing 71 peptides. Top ten novel bioactive peptides (i.e. CF, KM, ELPF, AM, ADHPH, LPR, PR, FR, PRM and GR) were then successfully identified and selected based on the amino acid sequences as well as the peptide interactions with ACE and DPP-4. Against ACE, IC50 of CF, KM, ELPF, AM, ADHPH, LPR, PR, FR, PRM and GR were 1.82, 1.89, 4.24, 3.07, 3.54, 1.30, 5.47, 4.35, 5.22 and 3.11 mM, respectively. These results were comparable to commercial inhibitor for ACE, captopril (IC50 = 3.98 mM). While against DPP-4, however, inhibitory activities were only comparable to other reported DPP-4 inhibitory peptides such as EK (IC50 = 3.22 mM) and GL (IC50 = 2.62 mM), as the peptides were able to achieve 2.99, 2.22, 9.92, 2.79, 1.66, 1.43, 4.11, 2.47, 2.50 and 2.83 mM, respectively
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    Characterisation And Crystallisation Of Deptor
    (Universiti Sains Malaysia, 2021-02)
    Yeap, Kean Heng
    The mechanistic target of rapamycin (mTOR) signalling pathway integrates wide varieties of nutrients to regulate important cellular processes related to cell growth. mTOR is a huge serine/threonine protein kinase and exists in two distinct complexes, mTORC1 and mTORC2. DEPTOR is an endogenous inhibitor of mTOR and consists of two DEP domains in tandem arrangement and a PDZ domain. The Escherichia coli expression system was used for cloning and expression experiments. Here, besides the full-length protein, various truncated mutants were designed as well to gain insights into the characteristics and architectures of the protein. Four truncated mutants were constructed to represent the first DEP domain (DEP1), the second DEP domain (DEP2), both DEP domains (DEP12) and the PDZ domain. DEPTOR, DEP1, DEP2 and DEP12 were expressed as soluble proteins but PDZ was insoluble.
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    Choline Chloride – Citric Acid Monohydrate Based Deep Eutectic Solvents As Alternative Media For Averrhoa Bilimbi Pectin (Abp) Extraction And As Plasticizers For Abp Bioplastic
    (Universiti Sains Malaysia, 2021-03)
    Shafie, Muhammad Hakimin
    Averrhoa bilimbi is an abundance and underutilized fruit. The extraction of pectin using strong acids and mineral acids produce hazardous effluents and low yield, respectively. Therefore, A. bilimbi fruit was suggested to be a good source of pectin whereas the deep eutectic solvent (DES) was suggested to be an environmental friendly and highly efficient medium for A. bilimbi pectin (ABP) extraction and as an alternative plasticizer for bioplastic (BP) production. The choline chloride – citric acid monohydrate based DES at different molar ratios (i.e. 3:1, 2:1, 1:1, 1:2 and 1:3) were successfully synthesized and DES 1:1 was found to meet the eutectic point. Results showed that increasing the molar ratio of citric acid monohydrate in DES, higher values of viscosity, surface tension and density were observed. Subsequently, these DESs were used as a medium for extraction of ABP. The result showed that DES-assisted extraction process required shorter time (30 minutes less) than citric acid monohydrate and the yield was higher (4.96% more) with optimal condition of 3.74% (w/v) of DES, an extraction temperature of 80 °C, and extraction time of 2.5 h. Apart from that, ABP-CAM was found lower in linearity with higher branch size of the pectin than ABP-DES. It was also observed that using DES as the extraction medium had improved the water and oil holding capacities (4.25 and 101.69%, respectively), foaming capacity (6.19%) and 2,2-diphenyl-1-picrylhydrazyl (DPPH) scavenging activity (43.56%) compared to ABP-CAM. Results also demonstrated that different molar ratios of DES components had significantly affected the structural properties of the extracted ABPs (i.e. linearity of pectin and branch size). Thus, affecting the functional properties. The potential of ABP as a source of biopolymer for BP production was also explored. The BP-ABP3:1, which was produced from ABP with large branch size, showed a higher value of melting temperature (175.30 °C), tensile stress (7.32 MPa) and modulus (33.64 MPa) due to the interaction of pectin chains was stronger. The BP-ABP3:1 also showed better barrier properties by obtaining the lowest water vapor transmission rates (1.10 – 1.18 mg/m2.s) and moisture absorption values (2.61 – 32.13%) depending on the relative humidity compared to other BP-ABPs that have linear structure with smaller branch size. Besides that, the influence of different molar ratios of components in DES as a plasticizer was investigated on the BP properties. It should be highlighted that DES at its eutectic point (molar ratio 1:1) exhibited minimal plasticizing effect due to the self-interaction of choline chloride and citric acid monohydrate. Also, the plasticizing effect increased when the molar ratio of citric acid monohydrate was higher. Furthermore, the selected BP-DES1:1 showed potential application as a capsule material by exhibiting its capability to withstand digestion in artificial saliva and fully dissolved in simulated gastric fluid, not cytotoxic, as well as provide delayed action in the fish oil oxidation process. In conclusion, this DES is a good alternative for pectin extraction, and as a plasticizer for BP production. These findings demonstrated that pectin extracted from A. bilimbi could be explored as novel promising natural pharmacological biopolymer and/or potential functional food ingredient.