Displaying publications 1 - 20 of 107 in total

  1. Lee SY, Kamarul T
    Int J Biol Macromol, 2014 Mar;64:115-22.
    PMID: 24325858 DOI: 10.1016/j.ijbiomac.2013.11.039
    In this study, a chitosan co-polymer scaffold was prepared by mixing poly(vinyl alcohol) (PVA), NO, carboxymethyl chitosan (NOCC) and polyethylene glycol (PEG) solutions to obtain desirable properties for chondrocyte cultivation. Electron beam (e-beam) radiation was used to physically cross-link these polymers at different doses (30 kGy and 50 kGy). The co-polymers were then lyophilized to form macroporous three-dimensional (3-D) matrix. Scaffold morphology, porosity, swelling properties, biocompatibility, expression of glycosaminoglycan (GAG) and type II collagen following the seeding of primary chondrocytes were studied up to 28 days. The results demonstrate that irradiation of e-beam at 50 kGy increased scaffold porosity and pore sizes subsequently enhanced cell attachment and proliferation. Scanning electron microscopy and transmission electron microscopy revealed extensive interconnected microstructure of PVA-PEG-NOCC, demonstrated cellular activities on the scaffolds and their ability to maintain chondrocyte phenotype. In addition, the produced PVA-PEG-NOCC scaffolds showed superior swelling properties, and increased GAG and type II collagen secreted by the seeded chondrocytes. In conclusion, the results suggest that by adding NOCC and irradiation cross-linking at 50 kGy, the physical and biological properties of PVA-PEG blend can be further enhanced thereby making PVA-PEG-NOCC a potential scaffold for chondrocytes.
  2. Lee SY, Shaari K
    Phytochem Anal, 2021 Sep 07.
    PMID: 34490671 DOI: 10.1002/pca.3084
    INTRODUCTION: Stevia is known for its sweet taste, attributed to the presence of steviol glycosides. Although reports on the dynamic changes of steviol glycosides during development of stevia are available, the data are mainly focused on stevioside and rebaudioside A. Information concerning the comprehensive metabolite profile of stevia in relation to different developmental stages is still lacking.

    OBJECTIVE: This study investigated the metabolite changes along the developmental stages of a local stevia cultivar.

    METHODOLOGY: Stevia leaves were harvested at 4 different developmental stages (early vegetative, late vegetative, budding, and flowering). Samples were then subjected to LC-MS metabolomics analysis to determine the metabolite variations.

    RESULTS: A total of 55 metabolites, comprising phenolic acids, flavonoids, and terpenoids were identified by MS/MS analysis of the stevia leaf extracts, revealing a metabolite profile which was comparatively similar with those of cultivars grown in other countries. PLS-DA differentiated the early vegetative stage stevia leaf samples from those of the later stages by higher content of phenolic acids. The leaf metabolomes of the later 3 stages (late vegetative, budding, and flowering) were collectively richer in flavonoids. Meanwhile, the content of steviol glycosides is highest during the late vegetative and budding stages.

    CONCLUSION: The present study provided, for the first time, a general overview of the metabolite variations with regard to the different developmental stages of stevia. The information may facilitate decision making of suitable harvesting times for higher yields of steviol glycosides or a more balanced metabolite profile in terms of pharmacologically useful metabolites.

  3. Loh SY, Lee SY, Murray L
    Asian Pac J Cancer Prev, 2014;15(19):8127-34.
    PMID: 25338995
    BACKGROUND: Qigong is highly favoured among Asian breast cancer survivors for enhancing health. This study examined the hypothesis that quality of life (QoL) in the Qigong group is better than the placebo (aerobic) or usual care group.

    MATERIALS AND METHODS: A total of 197 participants were randomly assigned to either the 8-week Kuala Lumpur Qigong Trial or control groups in 2010-2011. Measurement taken at baseline and post- intervention included QoL, distress and fatigue. Analysis of covariance (ANCOVA) and Kruskal Wallis were used to examine for differences between groups in the measurements.

    RESULTS: There were 95 consenting participants in this 8week trial. The adherence rates were 63% for Qigong and 65% for the placebo group. The Qigong group showed significant marginal improvement in Quality of life scores compared to placebo (mean difference=7.3 unit; p=0.036), compared to usual care (mean difference=6.7 unit; p=0.048) on Functional Assessment Cancer Therapy-Breast measure. There were no significant changes between the placebo and usual care groups in fatigue or distress at post intervention (8-week).

    CONCLUSIONS: Cancer survivors who participated in the Qigong intervention showed slightly better QOL. Follow up studies are greatly needed to evaluate which subgroups may best benefit from Qigong. With a steep rise of cancer survivors, there is an urgent need to explore and engage more cultural means of physical activity to fight side effects of treatment and for cancer control in developing countries.

  4. Loh SY, Chew SL, Lee SY
    Asian Pac J Cancer Prev, 2011;12(6):1483-8.
    PMID: 22126486
    BACKGROUND: Many cancer survivors are still not active enough to reap the benefits of physical activity. This study aimed to explore the correlation between perceived barriers and participation in exercise among multi- ethnic Malaysian women with breast cancer.

    METHODS: A cross-sectional study using a pre-post questionnaire and a media-clip as a cancer control strategy was conducted on a random sample of women with breast cancer. The tools were structured questionnaires to collect socio-medical demographic and physical activity data (e.g. barriers, exercise self-efficacy).

    RESULTS: A statistically significant relationship between level of physical activity before and after diagnosis of breast cancer (n=51, χ2=70.14, p<0.01) was found, whereby participants who rated more hours of physical activity before diagnosis were likely to persevere with exercise after diagnosis, r(49)=0.73, p<01. Some 76.5% of women engaged in low level activity and 23.5% of the participants engaged in moderate level of physical activity.

    CONCLUSIONS: Despite the many benefits of physical activity, the majority of survivors in this study were not found to be physically active, and did not even consciously think of exercise participation. Lack of time is the main barrier amongst those survivors who are predominantly 40-50 year old housewives juggling with household chores, childcare and/or job commitments. Public health messages stressing that short bouts of exercise or some exercise are better than no exercise needs to be emphasised consistently.
  5. Loh SY, Chew SL, Lee SY
    Asian Pac J Cancer Prev, 2011;12(1):87-94.
    PMID: 21517237
    INTRODUCTION: Physical activity participation amongst cancer survivors is low. This potent modifiable host factor has been disregarded in the cancer treatment plan for decades, despite its role in cancer control. The purpose of this study was to explore perception of physical activity among women with breast cancer.
    METHODS: Focus group with purposive sampling methods were conducted on women at different cancer trajectory - ie. completed treatment (n = 6) and undergoing treatment (n = 8). The taped discussions were transcribed verbatim and analyzed using a grounded theory approach. Concepts were identified as unique or shared between the two groups, and ordered into subcategories.
    RESULTS AND DISCUSSION: Three key categories on barriers to exercise; facilitator/motivator towards exercise; and myths around exercise were highlighted. There were more myths and reservations about physical activity in the UT (undergoing treatment) group, than in the CT (completed-treatment) group. Facilitators included positive experience from physical activity engagement, easy-access to facility, and good social support.
    CONCLUSIONS: Although both groups expressed difficulties in engaging in physical activity, the newly diagnosed have more negative perception of physical activity engagement. Both groups did not note the significant role of physical activity and cancer prevention/ recurrence, which is a key strategy to promote the uptake of exercise and acceptance of active lifestyle for cancer survivors. Health care clinicians like occupational therapists need to play greater public health role in educating and counseling lifestyle redesign for survivors living with cancer.
  6. Lee SY, Turjaman M, Mohamed R
    Trop Life Sci Res, 2018 Jul;29(2):13-28.
    PMID: 30112138 MyJurnal DOI: 10.21315/tlsr2018.29.2.2
    Indonesia is home to several tree taxa that are harvested for agarwood. This highly valuable oleoresin ironically was the cause for some species to become vulnerable due to gluttonous human activity. However, information on the genetic diversity of these endangered trees is limited. In this study, 28 specimens representing eight species from two genera, Aquilaria and Gyrinops, were collected from ex-situ and in-situ populations in Indonesia. Phylogenetic analysis conducted on DNA sequences of the nuclear ribosomal internal transcribed spacer (ITS) and the trnL-trnF intergenic spacer regions, revealed that Aquilaria and Gyrinops are paraphyletic when Aquilaria cumingiana is excluded. The phylogenetic analysis for ITS and trnL-trnF showed capability to categorise agarwood-producing species based on their regions: East Indonesia and West Indonesia, using Wallace's Line as the divider. In addition, we discuss challenges in species identification and taxonomy of agarwood-producing genera, and their conservation efforts in Indonesia.
  7. Lee SY, Fazlina N, Tye GJ
    Anal Biochem, 2019 09 15;581:113352.
    PMID: 31260647 DOI: 10.1016/j.ab.2019.113352
    DNA-templated silver nanocluster (AgNC), a new promising fluorescence probe has gained importance in biosensing and bioimaging in recent years. We employed a label-free AgNC to detect an intracellular transcription factor known as forkhead box p3 (FOXP3), which is the master regulator of regulatory T cells (Tregs) suppressive function. We developed an optimized method for the detection of messenger ribonucleic acid (mRNA) of FOXP3 by hybridizing AgNC and G-rich to the target FOXP3 mRNA of a MCF-7 cells. MCF-7 cells are chosen as a model as it readily expresses FOXP3. The hybridized samples were examined with UV illuminator and further verified with fluorescence spectroscopy, fluorescence microscope and flow cytometry. The successful hybridization of a three-way junction with AgNC, G-rich and mRNA FOXP3 target generated an improved fluorescence intensity with a spectral shift. We have successfully delivered the green fluorescing AgNC and G-rich into MCF-7 cells, producing a shift to red fluorescing cells corroborated by flow cytometry results. In summary, our approach enables the detection of intracellular FOXP3 nucleic acid and holds considerable potential in establishing a non-lethal intracellular detection system which would be crucial for the isolation of regulatory T-cells (Tregs) when combined with other cell surface markers.
  8. Lee SY, Ferdinand V, Siow LF
    Front Pharmacol, 2022;13:1003209.
    PMID: 36408266 DOI: 10.3389/fphar.2022.1003209
    Chamomile (Matricaria chamomilla L.) is a traditional medicinal plant used to treat hay fever, inflammation, muscle spasms, menstrual disorders, insomnia ulcers, wounds, gastrointestinal disorders, rheumatic pain, and hemorrhoids. Dried chamomile flowers have a longer shelf life and the dried extract in form of powder offers much flexibility for new therapeutic formulations as it could be used as a replacement for liquid extract and serve as a shelf-stable ingredient in new applications. This study aims to determine the effect of drying methods, i.e., convection oven-drying at 45 °C, freeze-drying at -50°C, and spray-drying at 140°C at 10.5 and 12 ml/min, respectively) on powder yield, physicochemical properties (moisture content, water activity, and color attributes), and total polyphenol content of chamomile extract powder. Our findings showed that spray-drying conducted at 140°C, 12 ml/min resulted in the lowest yield of powder (16.67%) compared to convection oven-drying (90.17%) and freeze-drying (83.24%). Decreasing the feed flow rate to 10.5 ml/min during spraying caused an increase in powder yield to 26.99%. The moisture content of spray-dried chamomile extract powder obtained at 140°C, 10.5 ml/min was higher (11.00%) compared to that of convection oven-dried (8.50%) and freeze-dried (7.50%). Both convection oven-dried and freeze-dried chamomile extract powder displayed no significant difference (p > 0.05) in moisture content. The higher feed flow rate (12 ml/min) in spray-drying also led to an increase in the moisture content of chamomile extract powder to 12.00%. The higher residual moisture found in the spray-dried samples resulted in partial agglomeration of particles. In terms of water activity, freeze-dried chamomile extract powder was found to have the highest water activity (0.63) compared to that of convection oven-dried (0.52), spray-dried at 140°C, 10.5 ml/min (0.57), and spray-dried at 140°C, 12 ml/min (0.58). Spray-dried and freeze-dried chamomile extract powder with high moisture content and water activity could be highly susceptible to microbial growth. In terms of color attributes, higher drying temperature in spray-drying led to darker, redder, and more yellowish chamomile extract powder that could be caused by heat-induced Maillard reaction and caramelization. Since lower drying temperature was used in both convection oven-drying and freeze-drying, both convection oven-dried (56.94 mg GAE/g powder) and freeze-dried chamomile extract powder (55.98 mg GAE/g powder) were found to have higher total polyphenol content compared to those of spray-dried (42.79-46.79 mg GAE/g powder). The present findings allow us to understand the effect of drying methods on the properties of chamomile extract powder and provide a better drying option to dry chamomile extract. Due to higher powder yield with ideal powder properties such as low moisture content and water activity, desirable color, and high total polyphenol content obtained from convection oven-drying, convection oven-drying was a better option than freeze-drying and spray-drying for drying chamomile extract.
  9. Hassan R, Lee SY, Morni WZW
    ScientificWorldJournal, 2017;2017:1489360.
    PMID: 28695188 DOI: 10.1155/2017/1489360
    Sea star (class Asteroidea, phylum Echinodermata) is one of the most successful marine organisms inhabiting a wide range of habitats. As one of the key stone species, sea stars are responsible for maintaining much of the local diversity of species within certain communities. Malaysian Exclusive Economic Zone (EEZ) Resource Survey had been carried out from 16th Aug to 6th Nov 2015 and one of the invertebrate by-catch organisms is sea star Stellaster childreni Gray, 1840. This study documents morphological characters and diet of the sea star, besides providing brief descriptions of the habitats based on particle size analysis and vessel log data sheet. A total of 217 individuals had been examined throughout this study. Fragments of flora and fauna were found in the gut including Mollusca (gastropod, bivalves, and scaphopods), sponge seagrass, and seaweed as well as benthic Foraminifera. Stellaster childreni were found at depth of 45 m to 185 m in the South China Sea off Sarawak Malaysia, with various sea bottom substrata. Approximately 41% of S. childreni were found at a mixture of sandy and muddy substratum, followed by mixture of sandy and coral (19.3%), muddy substratum (17.5%), coral substratum (11.5%), and sandy areas (10.6%). The widely distributed sea star on different types of sea beds suggested healthy deep sea ecosystem; thus Malaysia should explore further potential fisheries resources in the EEZ off Sarawak coast.
  10. Lee SY, Mustafa S, Ching YW, Shafee N
    Mol. Biol. (Mosk.), 2017 3 3;51(1):104-110.
    PMID: 28251972 DOI: 10.7868/S0026898417010116
    Both zinc and the α-subunit of hypoxia-inducible factor (HIF-1α) play important roles in the remodelling of mammary gland tissues. In the present study, we examined the level and the transcriptional activity of HIF-1α in mammary cells upon zinc treatment. In MCF-7 mammary adenocarcinoma and MCF-10A mammary epithelial cell lines, the toxicity levels of zinc differ. Interestingly, both cell lines overexpress HIF-1α following zinc treatment. As it was evident from an up-regulation of its specific target gene CA9 that encodes carbonic anhydrase IX, the stabilized HIF-1α translocated to the nucleus and was transcriptionally active. Hence, we conclude that zinc causes normoxic accumulation of transcriptionally active HIF-1α by interfering with its post-translational regulation.
  11. Fan L, Lee SY, Koay E, Harkensee C
    BMJ Case Rep, 2013;2013:bcr2013009558.
    PMID: 23608876 DOI: 10.1136/bcr-2013-009558
    Plasmodium knowlesi malaria is an uncommon, but highly prevalent parasitic infection in parts of Malaysia. This is the case of a 14-year-old Singaporean boy presenting to our emergency department with an 11-day history of fever following a school trip to Malaysia. Hepatosplenomegaly was the only clinical finding; laboratory tests showed thrombocytopaenia, lymphopaenia, mild anaemia and liver transaminitis. Specific malaria antigen tests were negative, but the peripheral blood film showed plasmodia with atypical features, with a parasite load of 0.5%. PCR confirmed the diagnosis of P knowlesi. The patient was successfully treated with chloroquine. The clinical course of P knowlesi malaria is indistinguishable from that of Plasmodium falciparum. This case highlights the importance of taking detailed travel history, careful examination of malaria blood films and judicious use of molecular techniques. Antigen tests alone may have missed a malaria diagnosis altogether, while blood film examination may wrongly identify the species as Plasmodium malariae or P falciparum. Third-generation PCR assays can be used to reliably identify P knowlesi.
  12. Chua LS, Lee SY, Abdullah N, Sarmidi MR
    Fitoterapia, 2012 Dec;83(8):1322-35.
    PMID: 22521793 DOI: 10.1016/j.fitote.2012.04.002
    Labisia pumila is a traditional herb widely used as post-partum medication for centuries. Recently, extensive researches have been carried out on the phytochemical identification, biological and toxicological studies for the herb. Phytochemicals found in the herbal extract showed high antioxidant properties, which were essential for various pharmacological activities. The significant findings are anti-estrogenic deficiency and -immunodeficiency diseases. Another finding that has considerable impact on natural product research is the contribution of L. pumila in promoting skin collagen synthesis. The performance of the herb as anti-aging agent due to natural aging process and accelerated by UV radiation was reviewed critically.
  13. Loh SY, Chew SL, Lee SY, Quek KF
    Asian Pac J Cancer Prev, 2011;12(6):1497-501.
    PMID: 22126488
    INTRODUCTION: Today, cancer survivors have an added new role to self manage living with the medical, emotional and role tasks that can affect their quality of life (QOL). The purpose of the study was to evaluate the QOL of women two years after participating in a self-management intervention program.

    METHOD: The clinical trial was conducted at University Malaya Medical Centre between 2006 and 2008. The experimental group underwent a 4-week self management program, and the control group underwent usual care. Two years after the intervention, questionnaires were randomly posted out to the participants.

    RESULTS: A total of 51 questionnaires returned. There were statistically differences between groups in psychological, self-care, mobility and participation aspects in PIPP (p<0.05). The experimental group reported having higher confidence to live with breast cancer compared to control group (p<0.05). There were significant between-group changes in anxiety scores at T2 (immediately after intervention) to T4 (two years later), and the differences in anxiety scores within groups between time point T2 and T4 were significantly different (p<0.05).

    CONCLUSION: The SAMA program is potentially capable to serve as a model intervention for successful transition to survivorship following breast cancer treatment. The program needs to be further tested for efficacy in a larger trial involving more diverse populations of women completing breast cancer treatment.

  14. Loh SY, Lee SY, Quek KF, Murray L
    Asian Pac J Cancer Prev, 2012;13(12):6337-42.
    PMID: 23464455
    BACKGROUND: Clinical trials on cancer subjects have one of the highest dropout rates. Barriers to recruitment range from patient-related, through institutional-related to staff-related factors. This paper highlights the low response rate and the recruitment barriers faced in our Qigong exercises trial.

    MATERIALS AND METHOD: The Qigong trial is a three-arm trial with a priori power size of 114 patients for 80% power. The University Malaya Medical Centre database showed a total of 1,933 patients from 2006-2010 and 751 patients met our inclusion criteria. These patients were approached via telephone interview. 131 out of 197 patients attended the trial and the final response rate was 48% (n=95/197).

    RESULTS: Multiple barriers were identified, and were regrouped as patient- related, clinician-related and/or institutional related. A major consistent barrier was logistic difficulty related to transportation and car parking at the Medical Centre. conclusions: All clinical trials must pay considerable attention to the recruitment process and it should even be piloted to identify potential barriers and facilitators to reduce attrition rate in trials.

  15. Lee SY, Mediani A, Ismail IS, Maulidiani, Abas F
    BMC Complement Altern Med, 2019 Jan 07;19(1):7.
    PMID: 30616569 DOI: 10.1186/s12906-018-2413-4
    BACKGROUND: Neptunia oleracea is a plant cultivated as vegetable in Southeast Asia. Previous works have revealed the potential of this plant as a source of natural antioxidants and α-glucosidase inhibitors. Continuing our interest on this plant, the present work is focused in identification of the bioactive compounds from different polarity fractions of N. oleracea, namely hexane (HF), chloroform (CF), ethyl acetate (EF) and methanol (MF).

    METHODS: The N. oleracea fractions were obtained using solid phase extraction (SPE). A metabolomics approach that coupled the use of proton nuclear magnetic resonance (1H NMR) with multivariate data analysis (MVDA) was applied to distinguish the metabolite variations among the N. oleracea fractions, as well as to assess the correlation between metabolite variation and the studied bioactivities (DPPH free radical scavenging and α-glucosidase inhibitory activities). The bioactive fractions were then subjected to ultra-high performance liquid chromatography tandem mass spectrometry (UHPLC-MS/MS) analysis to profile and identify the potential bioactive constituents.

    RESULTS: The principal component analysis (PCA) discriminated EF and MF from the other fractions with the higher distributions of phenolics. Partial least squares (PLS) analysis revealed a strong correlation between the phenolics and the studied bioactivities in the EF and the MF. The UHPLC-MS/MS profiling of EF and MF had tentatively identified the phenolics present. Together with some non-phenolic metabolites, a total of 37 metabolites were tentatively assigned.

    CONCLUSIONS: The findings of this work supported that N. oleracea is a rich source of phenolics that can be potential antioxidants and α-glucosidase inhibitors for the management of diabetes. To our knowledge, this study is the first report on the metabolite-bioactivity correlation and UHPLC-MS/MS analysis of N. oleracea fractions.

  16. Lee SY, Wong WF, Dong J, Cheng KK
    Molecules, 2020 Aug 20;25(17).
    PMID: 32825228 DOI: 10.3390/molecules25173783
    Macrophage activation is a key event that triggers inflammatory response. The activation is accompanied by metabolic shift such as upregulated glucose metabolism. There are accumulating evidences showing the anti-inflammatory activity of Momordica charantia. However, the effects of M. charantia on inflammatory response and glucose metabolism in activated macrophages have not been fully established. The present study aimed to examine the effect of M. charantia in modulating lipopolysaccharide (LPS)-induced inflammation and perturbed glucose metabolism in RAW264.7 murine macrophages. The results showed that LPS-induced NF-κB (p65) nuclear translocation was inhibited by M. charantia treatment. In addition, M. charantia was found to reduce the expression of inflammatory genes including IL6, TNF-α, IL1β, COX2, iNOS, and IL10 in LPS-treated macrophages. Furthermore, the data showed that M. charantia reduced the expression of GLUT1 and HK2 genes and lactate production (-28%), resulting in suppression of glycolysis. Notably, its effect on GLUT1 gene expression was found to be independent of LPS-induced inflammation. A further experiment also indicated that the bioactivities of M. charantia may be attributed to its key bioactive compound, charantin. Taken together, the study provided supporting evidences showing the potential of M. charantia for the treatment of inflammatory disorders.
  17. Pern YC, Lee SY, Ng WL, Mohamed R
    3 Biotech, 2020 Mar;10(3):103.
    PMID: 32099744 DOI: 10.1007/s13205-020-2072-2
    Tree species in the Aquilarieae tribe of the Thymelaeaceae family produce agarwood, a natural product highly valued for its fragrance, but the species are under threat due to indiscriminate harvesting. For conservation of these species, molecular techniques such as DNA profiling have been used. In this study, we assessed cross-amplification of microsatellite markers, initially developed for three Aquilaria species (A.crassna, A.malaccensis, and A.sinensis), on ten other agarwood-producing species, including members of Aquilaria (A.beccariana, A.hirta, A.microcarpa, A.rostrata, A.rugosa, A.subintegra, and A.yunnanensis) and Gyrinops (G.caudata, G.versteegii, and G.walla), both from the Aquilarieae tribe. Primers for 18 out of the 30 microsatellite markers successfully amplified bands of expected sizes in 1 sample each of at least 10 species. These were further used to genotype 74 individuals representing all the 13 studied species, yielding 13 cross-amplifiable markers, of which only 1 being polymorphic across all species. At each locus, the number of alleles ranged from 7 to 23, indicating a rather high variability. Four markers had relatively high species discrimination power. Our results demonstrated that genetic fingerprinting can be an effective tool in helping to manage agarwood genetic resources by potentially supporting the chain-of-custody of agarwood and its products in the market.
  18. Che Zain MS, Osman MF, Lee SY, Shaari K
    Molecules, 2021 Feb 19;26(4).
    PMID: 33669484 DOI: 10.3390/molecules26041084
    Luteolin and apigenin derivatives present in oil palm (Elaeis guineensis) leaves (OPL) are reported to possess excellent antioxidant properties relating to numerous health benefits. To meet the global demand for flavonoids, OPL, which is plentifully generated as an agricultural by-product from oil palm plantations, can be further exploited as a new source of natural antioxidant compounds. However, to produce a standardized herbal preparation, validation of the quantification method for these compounds is required. Therefore, in this investigation, we developed and validated an improved and rapid analytical method, ultra-high-performance liquid chromatography equipped with ultraviolet/photodiode array (UHPLC-UV/PDA) for the quantification of 12 luteolin and apigenin derivatives, particularly focusing on flavonoid isomeric pairs: orientin/isoorientin and vitexin/isovitexin, present in various OPL extracts. Several validation parameters were assessed, resulting in the UHPLC-UV/PDA technique offering good specificity, linearity, accuracy, precision, and robustness, where the values were within acceptable limits. Subsequently, the validated method was employed to quantify luteolin and apigenin derivatives from OPL subjected to different drying treatments and extraction with various solvent systems, giving total luteolin (TLC) and apigenin content (TAC) in the range of 2.04-56.30 and 1.84-160.38 µg/mg extract, respectively. Additionally, partial least square (PLS) analysis disclosed the combination of freeze dry-aqueous methanol yielded OPL extracts with high TLC and TAC, which are strongly correlated with antioxidant activity. Therefore, we provide the first validation report of the UHPLC-UV/PDA method for quantification of luteolin and apigenin derivatives present in various OPL extracts, suggesting that this approach could be employed in standardized herbal preparations by adopting orientin, isoorientin, vitexin, and isovitexin as chemical markers.
  19. Lee SY, Ng WL, Hishamuddin MS, Mohamed R
    Mitochondrial DNA B Resour, 2019;4(1):19-20.
    PMID: 33365402 DOI: 10.1080/23802359.2018.1535848
    Known for its durable timber quality, Neobalanocarpus heimii (King) Ashton is a highly sought after tree species endemic to the Malay Peninsula. Due to its scarcity and high value, the tree is classified under the IUCN Red List categories of Vulnerable. In this study, we assembled the complete chloroplast (cp) genome of N. heimii using data from high-throughput Illumina sequencing. The Chengal cp genome is 151,191 bp in size and includes two inverted repeat regions of 23,721 bp each, which is separated by a large single copy region of 83,801 bp and a small single copy region of 19,948 bp. A total of 130 genes were predicted, including 37 tRNA, 8 rRNA, and 85 protein-coding genes. Phylogenetic analysis placed N. heimii within the order Malvales.
  20. Lee SY, Liu BL, Wu JY, Chang YK
    Food Chem, 2021 Feb 15;338:128144.
    PMID: 33092004 DOI: 10.1016/j.foodchem.2020.128144
    A weak ion-exchange membrane (P-COOH) was synthesized by alkaline hydrolysis of a polyacrylonitrile nanofiber membrane prepared by electrospinning process. The P-COOH membrane was characterized for its physical properties and its application for purification of lysozyme from chicken egg white was investigated. The lysozyme adsorption efficiency of the P-COOH membrane operating in a stirred cell contactor (Millipore, Model 8010) was evaluated. The effects of key parameters such as the feed concentration, the rotating speed, the flow rate of feed and the operating pressure were studied. The results showed successful purification of lysozyme with a high recovery yield of 98% and a purification factor of 63 in a single step. The purification strategy was scaled-up to the higher feedstock loading volume of 32.7 and 70 mL using stirred cell contactors of Model 8050 and 8200, respectively. The scale-up processes achieved similar purification results, proving linear scalability of the purification technique adopted.
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