Displaying publications 1 - 20 of 38 in total

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  1. A Comprehensive Review on L-Asparaginase and Its Applications
    Batool T, Makky EA, Jalal M, Yusoff MM
    Appl Biochem Biotechnol, 2016 Mar;178(5):900-23.
    PMID: 26547852 DOI: 10.1007/s12010-015-1917-3
    L-asparaginase (LA) catalyzes the degradation of asparagine, an essential amino acid for leukemic cells, into ammonia and aspartate. Owing to its ability to inhibit protein biosynthesis in lymphoblasts, LA is used to treat acute lymphoblastic leukemia (ALL). Different isozymes of this enzyme have been isolated from a wide range of organisms, including plants and terrestrial and marine microorganisms. Pieces of information about the three-dimensional structure of L-asparaginase from Escherichia coli and Erwinia sp. have identified residues that are essential for catalytic activity. This review catalogues the major sources of L-asparaginase, the methods of its production through the solid state (SSF) and submerged (SmF) fermentation, purification, and characterization as well as its biological roles. In the same breath, this article explores both the past and present applications of this important enzyme and discusses its future prospects.
  2. A heat capacity model of T3/2 dependence for quantum dots
    Roslee AE, Muzakir SK, Ismail J, Yusoff MM, Jose R
    Phys Chem Chem Phys, 2016 Dec 21;19(1):408-418.
    PMID: 27905607 DOI: 10.1039/c6cp07173b
    This article addresses the heat capacity of quantum dots (QDs) using density functional theory (DFT). By analyzing the evolution of phonon density of states and heat capacity as CdSe clusters grow from a molecular cluster into larger quantum confined solids, we have shown that their heat capacity does not fit very well with the Debye T3 model. We observed that the number of phonon modes, which is discrete, increases as the particles grow, and the dispersion relation shows a quadratic behavior in contrast to the bulk solids whose dispersion relation is linear and equal to the sound velocity. The phonon density of states showed a square root variation with respect to frequency whereas that of the bulk is a quadratic variation of frequency. From the observed variation in the phonon density of states and holding the fact that the atomic vibrations in solids are elastically coupled, we have re-derived the expression for total energy of the QDs and arrive at a T3/2 model of heat capacity, which fits very well to the observed heat capacity data. These results give promising directions in the understanding of the evolution of the thermophysical properties of solids.
  3. Fulltext Antidiabetic Effect of Oral Borapetol B Compound, Isolated from the Plant Tinospora crispa, by Stimulating Insulin Release
    Lokman FE, Gu HF, Wan Mohamud WN, Yusoff MM, Chia KL, Ostenson CG
    Evid Based Complement Alternat Med, 2013;2013:727602.
    PMID: 24319481 DOI: 10.1155/2013/727602
    Aims. To evaluate the antidiabetic properties of borapetol B known as compound 1 (C1) isolated from Tinospora crispa in normoglycemic control Wistar (W) and spontaneously type 2 diabetic Goto-Kakizaki (GK) rats. Methods. The effect of C1 on blood glucose and plasma insulin was assessed by an oral glucose tolerance test. The effect of C1 on insulin secretion was assessed by batch incubation and perifusion experiments using isolated pancreatic islets. Results. An acute oral administration of C1 improved blood glucose levels in treated versus placebo groups with areas under glucose curves 0-120 min being 72 ± 17 versus 344 ± 10 mmol/L (P < 0.001) and 492 ± 63 versus 862 ± 55 mmol/L (P < 0.01) in W and GK rats, respectively. Plasma insulin levels were increased by 2-fold in treated W and GK rats versus placebo group at 30 min (P < 0.05). C1 dose-dependently increased insulin secretion from W and GK isolated islets at 3.3 mM and 16.7 mM glucose. The perifusions of isolated islets indicated that C1 did not cause leakage of insulin by damaging islet beta cells (P < 0.001). Conclusion. This study provides evidence that borapetol B (C1) has antidiabetic properties mainly due to its stimulation of insulin release.
  4. Application of polymerized multiporous nanofiber of SnO2 for designing a bienzyme glucose biosensor based on HRP/GOx
    Alim S, Kafi AKM, Rajan J, Yusoff MM
    Int J Biol Macromol, 2019 Feb 15;123:1028-1034.
    PMID: 30465828 DOI: 10.1016/j.ijbiomac.2018.11.171
    This work reports on a novel glucose biosensor based on co-immobilization of glucose oxidase (GOx) and horseradish peroxidase with polymerized multiporous nanofiber (MPNFs) of SnO2 onto glassy carbon electrode with chitosan. Multiporous nanofibers of SnO2 were synthesized by electrospinning method from the tin precursor which possesses high surface area good electrical conductivity, and the nanofibers were polymerized with polyaniline (PANI). GOx and HRP were then co-immobilized with the nanofibers on the surface of the glassy carbon electrode by using chitosan. The polymerized nanofibers play a significant role in facilitating the direct electron transfer between the electroactive center of the immobilized enzyme and the electrode surface. The morphology of the nanofiber and polymerized nanofiber has been evaluated by field emission scanning electron microscopy (FESEM). Cyclic Voltammetry and amperometry were employed to study and optimize the performance of the fabricated biosensor. The PANI/SnO2-NF/GOx-HRP/Ch/GC biosensor displayed a linear amperometric response towards the glucose concentration range from 5 to 100 μM with a detection limit of 1.8 μM (S/N = 3). Also, the anti-interference study and real sample analysis was investigated. Furthermore, the biosensor reported in this work exhibited excellent stability, reproducibility, and repeatability.
  5. Fulltext Assessing the role of urban green spaces for human well-being: a systematic review
    Jabbar M, Yusoff MM, Shafie A
    GeoJournal, 2021 Jul 20.
    PMID: 34305268 DOI: 10.1007/s10708-021-10474-7
    Human has been evolving in a natural environment over a long time; thus, he is habitual to adapt it. Green spaces are obligatory landscapes in an urban structure that provide a natural environment and accelerate other life events. In contrast, unplanned urbanization, and conversion from green to grey structures have damaged natural environmental resources. Studies through different angles have highlighted the importance of urban green spaces for human well-being but now need to identify their role according to the potential. The demands of urban green spaces may differ with the change of population size, types of grey structure, urban expansion, the altitude of the place, and geographical location. Therefore, this systematic review aims to analyse the significance of urban green spaces for human well-being. The study opted for a systematic process during the selection and organization of studies for this review. After analysing, 46 studies were finalized with the consensus of three review authors. Accordingly, literature was analysed under the central theme of "Urban Green Spaces for Human Well-being." Human Well-being was assessed under six sub-themes; physical, psychological, mental, social, subjective, and environmental well-being. The review concluded that urban green spaces are the primary pillar for a sustainable urban place and human well-being due to highly positive and positive correlations. Moreover, the study did not find any demarcation line between green spaces and grey structures according to any specific need. Therefore, the study suggested that the role of urban green spaces for human well-being should be analysed according to their potential and required optimal ratio under different communities' urban specific environments and social behaviour.
  6. Bio-waste corn-cob cellulose supported poly(hydroxamic acid) copper complex for Huisgen reaction: Waste to wealth approach
    Mandal BH, Rahman ML, Yusoff MM, Chong KF, Sarkar SM
    Carbohydr Polym, 2017 Jan 20;156:175-181.
    PMID: 27842811 DOI: 10.1016/j.carbpol.2016.09.021
    Corn-cob cellulose supported poly(hydroxamic acid) Cu(II) complex was prepared by the surface modification of waste corn-cob cellulose through graft copolymerization and subsequent hydroximation. The complex was characterized by IR, UV, FESEM, TEM, XPS, EDX and ICP-AES analyses. The complex has been found to be an efficient catalyst for 1,3-dipolar Huisgen cycloaddition (CuAAC) of aryl/alkyl azides with a variety of alkynes as well as one-pot three-components reaction in the presence of sodium ascorbate to give the corresponding cycloaddition products in up to 96% yield and high turn over number (TON 18,600) and turn over frequency (TOF 930h-1) were achieved. The complex was easy to recover from the reaction mixture and reused six times without significant loss of its catalytic activity.
  7. Fulltext Biosynthesis of metallic nanoparticles using plant derivatives and their new avenues in pharmacological applications - An updated report
    Kuppusamy P, Yusoff MM, Maniam GP, Govindan N
    Saudi Pharm J, 2016 Jul;24(4):473-84.
    PMID: 27330378 DOI: 10.1016/j.jsps.2014.11.013
    The field of nanotechnology mainly encompasses with biology, physics, chemistry and material sciences and it develops novel therapeutic nanosized materials for biomedical and pharmaceutical applications. The biological syntheses of nanoparticles are being carried out by different macro-microscopic organisms such as plant, bacteria, fungi, seaweeds and microalgae. The biosynthesized nanomaterials have been effectively controlling the various endemic diseases with less adverse effect. Plant contains abundant natural compounds such as alkaloids, flavonoids, saponins, steroids, tannins and other nutritional compounds. These natural products are derived from various parts of plant such as leaves, stems, roots shoots, flowers, barks, and seeds. Recently, many studies have proved that the plant extracts act as a potential precursor for the synthesis of nanomaterial in non-hazardous ways. Since the plant extract contains various secondary metabolites, it acts as reducing and stabilizing agents for the bioreduction reaction to synthesized novel metallic nanoparticles. The non-biological methods (chemical and physical) are used in the synthesis of nanoparticles, which has a serious hazardous and high toxicity for living organisms. In addition, the biological synthesis of metallic nanoparticles is inexpensive, single step and eco-friendly methods. The plants are used successfully in the synthesis of various greener nanoparticles such as cobalt, copper, silver, gold, palladium, platinum, zinc oxide and magnetite. Also, the plant mediated nanoparticles are potential remedy for various diseases such as malaria, cancer, HIV, hepatitis and other acute diseases.
  8. Carbonyl Functionalized Single-Walled Carbon Nanotube-Hb Crosslinked Network: A Novel Platform for Studying Bio-Electrochemistry and Electrocatalysis of Hemoglobin
    Kafi AKM, Yam CCL, Azmi NS, Yusoff MM
    J Nanosci Nanotechnol, 2018 Apr 01;18(4):2422-2428.
    PMID: 29442911 DOI: 10.1166/jnn.2018.14327
    In this work, the direct electrochemistry of hemoglobin (Hb), which was immobilized on carbonyl functionalized single walled carbon nanotube (SWCNT) and deposited onto a gold (Au) electrode has been described. The synthesis of the network of crosslinked SWCNT/Hb was done with the help of crosslinking agent EDC (1-ethyl-3-(3-dimethylaminopropyl) carbodiimide). The UV-Vis and FTIR spectroscopy of SWCNT/Hb networks showed that Hb maintained its natural structure and kept good stability. In addition with this, scanning electron microscopy (SEM) illustrated that SWCNT/Hb networks had a featured layered structure and Hb being strongly liked with SWCNT surface. Cyclic voltammetry (CV) was used to study and to optimize the performance of the resulting modified electrode. The cyclic voltammetric (CV) responses of SWCNT/Hb networks in pH 7.0 exhibit prominent redox couple for the FeIII/II redox process with a midpoint potential of -0.46 V and -0.34, cathodic and anodic respectively. Furthermore, SWCNT/Hb networks are utilized for the detection of hydrogen peroxide (H2O2). Electrochemical measurements reveal that the resulting SWCNT/Hb electrodes display high electrocatalytic activity to H2O2 with high sensitivity, wide linear range, and low detection limit. Overall, the electrochemical results are due to excellent biocompatibility and excellent electron transport efficiency of CNT as well as high Hb loading and synergistic catalytic effect of the modified electrode toward H2O2.
  9. Chemical characterization and antimicrobial activity of rhizome essential oils of very closely allied Zingiberaceae species endemic to Borneo: Alpinia ligulata K. Schum. and Alpinia nieuwenhuizii Val
    Yusoff MM, Ibrahim H, Hamid NA
    Chem Biodivers, 2011 May;8(5):916-23.
    PMID: 21560240 DOI: 10.1002/cbdv.201000270
    Two poorly studied, morphologically allied Alpinia species endemic to Borneo, viz., A. ligulata and A. nieuwenhuizii, were investigated here for their rhizome essential oil. The oil compositions and antimicrobial activities were compared with those of A. galanga, a better known plant. A fair number of compounds were identified in the oils by GC-FID and GC/MS analyses, with large differences in the oil composition between the three species. The rhizome oil of A. galanga was rich in 1,8-cineole (29.8%), while those of A. ligulata and A. nieuwenhuizii were both found to be extremely rich in (E)-methyl cinnamate (36.4 and 67.8%, resp.). The three oils were screened for their antimicrobial activity against three Gram-positive and three Gram-negative bacteria and two fungal species. The efficiency of growth inhibition of Staphylococcus aureus var. aureus was found to decline in the order of A. nieuwenhuizii>A. ligulata ∼ A. galanga, while that of Escherichia coli decreased in the order of A. galanga>A. nieuwenhuzii ∼ A. ligulata. Only the A. galanga oil inhibited the other bacteria and the fungi tested.
  10. Chemical composition of volatile oils of Aquilaria malaccensis (Thymelaeaceae) from Malaysia
    Tajuddin SN, Yusoff MM
    Nat Prod Commun, 2010 Dec;5(12):1965-8.
    PMID: 21299133
    Volatile oils of Aquilaria malaccensis Benth. (Thymelaeaceae) from Malaysia were obtained by hydrodistillation and subjected to detailed GC-FID and GC/MS analyses to determine possible similarities and differences in their chemical composition in comparison with the commercial oil. A total of thirty-one compounds were identified compared with twenty-nine identified in the commercial oil. The major compounds identified were 4-phenyl-2-butanone (32.1%), jinkoh-eremol (6.5%) and alpha-guaiene (5.8%), while the major compounds in the commercial oil were alpha-guaiene (10.3%), caryophellene oxide (8.6%), and eudesmol (3.2%). The results of the present study showed that more than nine sesquiterpene hydrocarbons were present, which is more than previously reported. Analysis also showed that the number of oxygenated sesquiterpenes in this study were much less than previously reported. Among the compounds detected were alpha-guaiene, beta-agarofuran, alpha-bulnesene, jinkoh-eremol, kusunol, selina-3,11-dien-9-one, oxo-agarospirol and guaia-1 (10), 11-dien-15,2-olide.
  11. Comparative analysis of antioxidant and antiproliferative activities of Rhodomyrtus tomentosa extracts prepared with various solvents
    Abd Hamid H, Mutazah R, Yusoff MM, Abd Karim NA, Abdull Razis AF
    Food Chem Toxicol, 2017 Oct;108(Pt B):451-457.
    PMID: 27725206 DOI: 10.1016/j.fct.2016.10.004
    Rhodomyrtus tomentosa (Aiton) Hassk. has a wide spectrum of pharmacological effects and has been used to treat wounds, colic diarrhoea, heartburns, abscesses and gynaecopathy. The potential antiproliferative activities of R. tomentosa extracts from different solvents were evaluated in vitro on HepG2, MCF-7 and HT 29 cell lines while antioxidant activity was monitored by radical scavenging assay (DPPH), copper reducing antioxidant capacity (CUPRAC) and β-carotene bleaching assay. Extracts from R. tomentosa show the viability of the cells in concentration-dependent manner. According to the IC50 obtained, the ethyl acetate extracts showed significant antiproliferative activity on HepG2 (IC50 11.47 ± 0.280 μg/mL), MCF-7 (IC50 2.68 ± 0.529 μg/mL) and HT 29 (IC50 16.18 ± 0.538 μg/mL) after 72 h of treatment. Bioassay guided fractionation of the ethyl acetate extract led to the isolation of lupeol. Methanol extracts show significant antioxidant activities in DPPH (EC50 110.25 ± 0.005 μg/ml), CUPRAC (EC50 53.84 ± 0.004) and β-carotene bleaching (EC50 58.62 ± 0.001) due to the presence of high total flavonoid and total phenolic content which were 110.822 ± 0.017 mg butylated hydroxytoluene (BHT)/g and 190.467 ± 0.009 mg gallic acid (GAE)/g respectively. Taken together, the results extracts show the R. tomentosa as a potential source of antioxidant and antiproliferative efficacy.
  12. Fulltext Comparison of high pressure and thermal pasteurization on the quality parameters of strawberry products: a review
    Nawawi NIM, Ijod G, Senevirathna SSJ, Aadil RM, Yusof NL, Yusoff MM, et al.
    Food Sci Biotechnol, 2023 May;32(6):729-747.
    PMID: 37041805 DOI: 10.1007/s10068-023-01276-3
    Strawberry (Fragaria ananassa) is rich in bioactive compounds with high antioxidant activity. High pressure processing (HPP) is an efficient alternative to preserve these bioactive compounds in terms of microbial inactivation and shelf-life stability. This review compares the effects of pasteurization methods using high pressure or thermal pasteurization (TP) on the quality parameters of various strawberry-based products. To summarize, most of the high pressure-treated products are microbiologically stable and showed minimum degradation of thermolabile compounds than TP-treated ones. However, some studies reported that high pressure did not have an advantage over TP especially in the preservation of phenolic phytochemicals during storage. The insufficient enzyme inactivation and high residual activity of enzymes after high pressure treatment could cause anthocyanins degradation thus affecting the product quality. Overall, this review could be valuable to potential processors in evaluating the effective commercialization of high pressure-treated strawberry products.
  13. Enhanced direct electron transfer of redox protein based on multiporous SnO2 nanofiber-carbon nanotube nanocomposite and its application in biosensing
    Alim S, Kafi AKM, Jose R, Yusoff MM, Vejayan J
    Int J Biol Macromol, 2018 Jul 15;114:1071-1076.
    PMID: 29625222 DOI: 10.1016/j.ijbiomac.2018.03.184
    A novel third generation H2O2 biosensor is fabricated using multiporous SnO2 nanofiber/carbon nanotubes (CNTs) composite as a matrix for the immobilization of redox protein onto glassy carbon electrode. The multiporous nanofiber (MPNFs) of SnO2 is synthesized by electrospinning technique from the tin precursor. This nanofiber shows high surface area and good electrical conductivity. The SnO2 nanofiber/CNT composite increases the efficiency of biomolecule loading due to its high surface area. The morphology of the nanofiber has been evaluated by scanning electron microscopy (SEM). Cyclic Voltammetry and amperometry technique are employed to study and optimize the performance of the fabricated electrode. A direct electron transfer between the protein's redox centre and the glassy carbon electrode is established after fabrication of the electrode. The fabricated electrode shows excellent electrocatalytic reduction to H2O2. The catalysis currents increases linearly to the H2O2 concentration in a wide range of 1.0 10-6-1.4×10-4M and the lowest detection limit was 30nM (S/N=3). Moreover, the biosensor showed a rapid response to H2O2, a good stability and reproducibility.
  14. Environment-Modulated Crystallization of Cu2O and CuO Nanowires by Electrospinning and Their Charge Storage Properties
    Harilal M, G Krishnan S, Pal B, Reddy MV, Ab Rahim MH, Yusoff MM, et al.
    Langmuir, 2018 02 06;34(5):1873-1882.
    PMID: 29345940 DOI: 10.1021/acs.langmuir.7b03576
    This article reports the synthesis of cuprous oxide (Cu2O) and cupric oxide (CuO) nanowires by controlling the calcination environment of electrospun polymeric nanowires and their charge storage properties. The Cu2O nanowires showed higher surface area (86 m2 g-1) and pore size than the CuO nanowires (36 m2 g-1). Electrochemical analysis was carried out in 6 M KOH, and both the electrodes showed battery-type charge storage mechanism. The electrospun Cu2O electrodes delivered high discharge capacity (126 mA h g-1) than CuO (72 mA h g-1) at a current density of 2.4 mA cm-2. Electrochemical impedance spectroscopy measurements show almost similar charge-transfer resistance in Cu2O (1.2 Ω) and CuO (1.6 Ω); however, Cu2O showed an order of magnitude higher ion diffusion. The difference in charge storage between these electrodes is attributed to the difference in surface properties and charge kinetics at the electrode. The electrode also shows superior cyclic stability (98%) and Coulombic efficiency (98%) after 5000 cycles. Therefore, these materials could be acceptable choices as a battery-type or pseudocapacitive electrode in asymmetric supercapacitors.
  15. Fulltext Evaluation of in-vitro antioxidant and antibacterial properties of Commelina nudiflora L. extracts prepared by different polar solvents
    Kuppusamy P, Yusoff MM, Parine NR, Govindan N
    Saudi J Biol Sci, 2015 May;22(3):293-301.
    PMID: 25972750 DOI: 10.1016/j.sjbs.2014.09.016
    The study explored on the commonly available weed plant Commelina nudiflora which has potential in-vitro antioxidant and antimicrobial activity. The different polar solvents such as ethanol, chloroform, dichloromethane, hexane and aqueous were used for the soxhlet extraction. The extracts were identified pharmacologically as important bioactive compounds and their potential free radical scavenging activities, and antimicrobial properties were studied. C. nudiflora extracts were monitored on their in-vitro antioxidant ability by DPPH and ABTS radical scavenging assay. Aqueous extract shows significant free radical scavenging activity of 63.4 mg/GAE and 49.10 mg/g in DPPH and ABTS respectively. Furthermore, the aqueous crude extract was used in antibacterial studies, which shows the highest inhibitory activity against Pseudomonas aeruginosa, Escherichia coli and Salmonella typhi. Among all the extracts, aqueous extract of C. nudiflora has significant control over free radical scavenging activity and inhibition of the growth of food pathogenic bacteria. Also, the aqueous extract contains abundance of phenolics and flavonoids higher than other extracts. This study explored weed plant C. nudiflora as a potential source of antioxidant and antibacterial efficacy and identified various therapeutic value bioactive compounds from GC-MS analysis.
  16. Flooding tolerance in Rice: adaptive mechanism and marker-assisted selection breeding approaches
    Haque MA, Rafii MY, Yusoff MM, Ali NS, Yusuff O, Arolu F, et al.
    Mol Biol Rep, 2023 Mar;50(3):2795-2812.
    PMID: 36592290 DOI: 10.1007/s11033-022-07853-9
    Natural and man-made ecosystems worldwide are subjected to flooding, which is a form of environmental stress. Genetic variability in the plant response to flooding involves variations in metabolism, architecture, and elongation development that are related with a low oxygen escape strategy and an opposing quiescence scheme that enables prolonged submergence endurance. Flooding is typically associated with a decrease in O2 in the cells, which is especially severe when photosynthesis is absent or limited, leading to significant annual yield losses globally. Over the past two decades, considerable advancements have been made in understanding of mechanisms of rice adaptation and tolerance to flooding/submergence. The mapping and identification of Sub1 QTL have led to the development of marker-assisted selection (MAS) breeding approach to improve flooding-tolerant rice varieties in submergence-prone ecosystems. The Sub1 incorporated in rice varieties showed tolerance during flash flood, but not during stagnant conditions. Hence, gene pyramiding techniques can be applied to combine/stack multiple resistant genes for developing flood-resilient rice varieties for different types of flooding stresses. This review contains an update on the latest advances in understanding the molecular mechanisms, metabolic adaptions, and genetic factors governing rice flooding tolerance. A better understanding of molecular genetics and adaptation mechanisms that enhance flood-tolerant varieties under different flooding regimes was also discussed.
  17. Functionalized core/shell nanofibers for the differentiation of mesenchymal stem cells for vascular tissue engineering
    Ezhilarasu H, Sadiq A, Ratheesh G, Sridhar S, Ramakrishna S, Ab Rahim MH, et al.
    Nanomedicine (Lond), 2019 01;14(2):201-214.
    PMID: 30526272 DOI: 10.2217/nnm-2018-0271
    AIM: Atherosclerosis is a common cardiovascular disease causing medical problems globally leading to coronary artery bypass surgery. The present study is to fabricate core/shell nanofibers to encapsulate VEGF for the differentiation of mesenchymal stem cells (MSCs) into smooth muscle cells to develop vascular grafts.

    MATERIALS & METHODS: The fabricated core/shell nanofibers contained polycaprolactone/gelatin as the shell, and silk fibroin/VEGF as the core materials.

    RESULTS: The results observed that the core/shell nanofibers interact to differentiate MSCs into smooth muscle cells by the expression of vascular smooth muscle cell (VSMC) contractile proteins α-actinin, myosin and F-actin.

    CONCLUSION: The functionalized polycaprolactone/gelatin/silk fibroin/VEGF (250 ng) core/shell nanofibers were fabricated for the controlled release of VEGF in a persistent manner for the differentiation of MSCs into smooth muscle cells for vascular tissue engineering.

  18. Fulltext GC-MS Based Metabolite Profiling, Antioxidant and Antimicrobial Properties of Different Solvent Extracts of Malaysian Plectranthus amboinicus Leaves
    Swamy MK, Arumugam G, Kaur R, Ghasemzadeh A, Yusoff MM, Sinniah UR
    Evid Based Complement Alternat Med, 2017;2017:1517683.
    PMID: 28424737 DOI: 10.1155/2017/1517683
    This study evaluates the phytochemistry, antioxidant, and antimicrobial effects of Plectranthus amboinicus leaves extracted in different solvents. The methanol extract contained the highest total phenolic (94.37 ± 1.24 mg GAE/g) and flavonoid contents (26.90 ± 1.35 mg RE/g) and exhibited the highest DPPH scavenging activity (90.13 ± 3.32%) followed by the acetone extract (80.23 ± 3.26%) at 500 μg/mL concentration. Similarly, the highest ferric ion reduction potential (849.63 ± 30.95 μM of Fe (II)/g dry weight) was exhibited by the methanol extract followed by the acetone extract (695.92 ± 25.44 μM of Fe (II)/g dry weight). The methanol extract showed greater antimicrobial activity against all the tested pathogens (Bacillus subtilis, Methicillin-resistant Staphylococcus aureus, Pseudomonas aeruginosa, Escherichia coli, and Candida albicans). However, both hexane and acetone extracts failed to inhibit E. coli. S. aureus and C. albicans were more susceptible to all the extracts. Further, GC-MS analysis confirmed the occurrence of a total 46 phytocompounds in different solvent extracts. Some of the major compounds included carvacrol (37.7%), tetracontane (16.6%), squalene (15.6%), tetrapentacontane (13.7%), and Phytol (12.9%). In conclusion, extraction solvents influenced the recovery of phytocompounds and the highest pharmacological activities of the methanol extract could be correlated to the presence of additional bioactive compounds.
  19. Hemoglobin Immobilization on Multiporous Nanofibers of SnO₂ and Chitosan Composite for Hydrogen Peroxide Sensing
    Kafi AKM, Alim S, Jose R, Yusoff MM
    J Nanosci Nanotechnol, 2019 04 01;19(4):2027-2033.
    PMID: 30486943 DOI: 10.1166/jnn.2019.15465
    A multiporous nanofiber (MPNFs) of SnO₂ and chitosan has been used for the immobilization of a redox protein, hemoglobin (Hb), onto the surface of glassy carbon electrode (GCE). The multiporous nanofiber of SnO₂ that has very high surface area is synthesized by using electrospinning technique through controlling the tin precursor concentration. Since the constructed MPNFs of SnO₂ exposes very high surface area, it increases the efficiency for biomolecule-loading. The morphology of fabricated electrodes is examined by SEM observation and the absorbance spectra of Hb/(MPNFs) of SnO₂ are studied by UV-Vis analysis. Cyclic Voltammetry and amperometry are employed to study and optimize the performance of the resulting fabricated electrode. After fabrication of the electrode with the Hb and MPNFs of SnO₂, a direct electron transfer between the protein's redox centre and the glassy carbon electrode was established. The modified electrode has showed a couple of redox peak located at -0.29 V and -0.18 V and found to be sensitive to H₂O₂. The fabricated electrode also exhibited an excellent electrocatalytic activity towards the reduction of H₂O₂. The catalysis currents increased linearly to the H₂O₂ concentration in a wide range of 5.0×10-6-1.5×10-4 M. Overall experimental results show that MPNFs of SnO₂ has a role towards the enhancement of the electroactivity of Hb at the electrode surface. Thus the MPNFs of SnO₂ is a very promising candidate for future biosensor applications.
  20. Highly porous of hydroxyethyl cellulose biocomposite scaffolds for tissue engineering
    Zulkifli FH, Hussain FSJ, Harun WSW, Yusoff MM
    Int J Biol Macromol, 2019 Feb 01;122:562-571.
    PMID: 30365990 DOI: 10.1016/j.ijbiomac.2018.10.156
    This study is focusing to develop a porous biocompatible scaffold using hydroxyethyl cellulose (HEC) and poly (vinyl alcohol) (PVA) with improved cellular adhesion profiles and stability. The combination of HEC and PVA were synthesized using freeze-drying technique and characterized using SEM, ATR-FTIR, TGA, DSC, and UTM. Pore size of HEC/PVA (2-40 μm) scaffolds showed diameter in a range of both pure HEC (2-20 μm) and PVA (14-70 μm). All scaffolds revealed high porosity above 85%. The water uptake of HEC was controlled by PVA cooperation in the polymer matrix. After 7 days, all blended scaffolds showed low degradation rate with the increased of PVA composition. The FTIR and TGA results explicit possible chemical interactions and mass loss of blended scaffolds, respectively. The Tg values of DSC curved in range of HEC and PVA represented the miscibility of HEC/PVA blend polymers. Higher Young's modulus was obtained with the increasing of HEC value. Cell-scaffolds interaction demonstrated that human fibroblast (hFB) cells adhered to polymer matrices with better cell proliferation observed after 7 days of cultivation. These results suggested that biocompatible of HEC/PVA scaffolds fabricated by freeze-drying method might be suitable for skin tissue engineering applications.
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