Displaying publications 21 - 40 of 437 in total

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  1. Mahmoodani F, Ghassem M, Babji AS, Yusop SM, Khosrokhavar R
    J Food Sci Technol, 2014 Sep;51(9):1847-56.
    PMID: 25190839 DOI: 10.1007/s13197-012-0742-8
    Skin and bone gelatins of pangasius catfish (Pangasius sutchi) were hydrolyzed with alcalase to isolate Angiotensin Converting Enzyme (ACE) inhibitory peptides. Samples with the highest degree of hydrolysis (DH) were separated into different fractions with molecular weight cut-off (MWCO) sizes of 10, 3 and 1 kDa, respectively and assayed for ACE inhibitory activity. Skin and bone gelatins had highest DH of 64.87 and 68.48 % after 2 and 1 h incubation, respectively. Results from this study indicated that by decreasing the molecular weight of fractions, ACE inhibitory activity was increased. Therefore, F3 permeates (MWCO 
    Matched MeSH terms: Inhibitory Concentration 50
  2. Ashraf Ali M, Ismail R, Choon TS, Kumar RS, Osman H, Arumugam N, et al.
    Bioorg Med Chem Lett, 2012 Jan 1;22(1):508-11.
    PMID: 22142546 DOI: 10.1016/j.bmcl.2011.10.087
    Pyrrolothiazolyloxindole analogues share vital pharmacological properties, considered useful in Alzheimer's disease (AD). The aim of this study was synthesis and evaluate pyralothiazolyloxindole analogues if possess acetyl cholinesterase (AChE) inhibitory activity. The easily accessible one-pot synthesis of these compounds resulted to be significantly less difficult and expensive than that of donepezil. Several compounds possess anti-cholinesterase activity in the order of micro and sub-micromolar. Particularly, compound was the most potent inhibitors of the series against acetyl cholinesterase enzyme with IC(50) 0.11μmol/L.
    Matched MeSH terms: Inhibitory Concentration 50
  3. Muhammad N, Din LB, Sahidin I, Hashim SF, Ibrahim N, Zakaria Z, et al.
    Molecules, 2012 Jul 30;17(8):9043-55.
    PMID: 22847143 DOI: 10.3390/molecules17089043
    A new resveratrol dimer, acuminatol (1), was isolated along with five known compounds from the acetone extract of the stem bark of Shorea acuminata. Their structures and stereochemistry were determined by spectroscopic methods, which included the extensive use of 2D NMR techniques. All isolated compounds were evaluated for their antioxidant activity using the 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging activity (RSA) and the β-carotene-linoleic acid (BCLA) assays, and compared with those of the standards of ascorbic acid (AscA) and butylated hydroxytoluene (BHT). All compounds tested exhibited good to moderate antioxidant activity in the DPPH assay (IC₅₀s 0.84 to 10.06 mM) and displayed strong inhibition of β-carotene oxidation (IC₅₀s 0.10 to 0.22 mM). The isolated compounds were evaluated on the Vero cell line and were found to be non-cytotoxic with LC₅₀ values between 161 to 830 µM.
    Matched MeSH terms: Inhibitory Concentration 50
  4. Zhong L, Liu Q, Ting YS, Thien VY, Binti Kalong NS, Yang D, et al.
    Chem Biol Drug Des, 2018 12;92(6):1998-2008.
    PMID: 30043441 DOI: 10.1111/cbdd.13371
    Overexpression of thioredoxin-interacting protein (TXNIP) is associated with reduced insulin sensitivity and β-cell apoptosis. We have previously shown that W2476 inhibited high glucose-induced TXNIP expression at both mRNA and protein levels in INS-1E cells. In this study, we describe structural modification and optimization of W2476 leading to three more active derivatives, 8d, 8g, and 9h, capable of suppressing TXNIP expression in BG73 and INS-1E cells, increasing insulin production, and reducing high glucose-induced apoptosis in INS-1E cells.
    Matched MeSH terms: Inhibitory Concentration 50
  5. Phirdaous Abbas, Yumi Zuhanis Has-Yun Hashim, Hamzah Mohd Salleh, Saripah Salbiah Syed Abdul Azzizz
    MyJurnal
    Uninfected agarwood branch is readily available as raw material in agarwood plantation as new practices of agarwood plantation scheme were opted as substitute to the endangered wild type agarwood. The uninfected branch can be easily obtained during pruning process (one of plantation’s common maintenance procedure), throughout the years before inoculation stage. This current study aimed to investigate the optimal extraction process conditions of agarwood branch using ethanol as solvent system for maximal yield, and assess its cytotoxic effects towards MCF-7 breast cancer cells. Uninfected branch of Aquilaria subintegra was subjected to One Factor at a Time (OFAT) and Response Surface Methodology (RSM)-guided ethanolic extraction to achieve maximal yield. The extract was then subjected to cytotoxicity, cell attachment and cell viability assays, respectively. Optimization Run 2 (temperature 45 °C, solid-liquid ratio of 1:30, 16 hours maceration) gave the highest agarwood branch ethanolic extract (ABEE) yield of 44.70 ± 18.9 mg/g dried material (DM). Meanwhile Run 7 (temperature 45 °C, solid-liquid ratio of 1:10, 16 hours of maceration) gave the lowest yield (19.34 ± 14.1 mg/g DM). However, while maintaining the 16 hour-maceration, the model predicted a slightly lower yield of 30.232 ± 0.266 mg/g DM of ABEE with process conditions of 45 °C and solid-liquid ratio of 1:19 when the desirable parameters were factored in namely using (ⅰ) the most suitable temperature (that does not risk the bioactivities of the extract), and (ⅱ) an economical volume of solvent. Crude ABEE obtained from the optimal process conditions resulted in cytotoxicity effects on MCF-7 breast cancer cells with IC50 estimate of 3.645 ± 0.099 μg/mL. The extract also affected MCF-7 cell attachment and viability with altered morphology. More work to elucidate the mechanism of actions of the extract are warranted; which could further lead to development of breast cancer natural product-based therapeutics.
    Matched MeSH terms: Inhibitory Concentration 50
  6. Ramli RA, Lie W, Pyne SG
    J Nat Prod, 2014 Apr 25;77(4):894-901.
    PMID: 24606395 DOI: 10.1021/np400978x
    Four new stichoneurine-type alkaloids, stichoneurines F and G (1-2) and sessilistemonamines E and F (3-4), have been isolated from the root extracts of Stichoneuron caudatum. The structures and relative configurations of these alkaloids have been determined by spectroscopic methods and molecular modeling experiments. Compounds 1-4 were tested for their acetylcholinesterase (AChE) inhibitory activities against human AChE. Compound 3 showed significant inhibitory activity with an IC50 value of 9.1±0.15 μM.
    Matched MeSH terms: Inhibitory Concentration 50
  7. Amin, I.M., Sheikh Abdul Kadir, S.H., Isa, M.R., Rosdy. N.M.M.N.M., Hasani NAH
    JUMMEC, 2016;19(1):1-10.
    MyJurnal
    The positive response to tamoxifen in ERa-positive breast cancer patients is usually of a short duration as many
    of the patients eventually develop resistance. Our preliminary results show that aloe emodin extracted from
    the leaves of the Aloe barbadensis Miller demonstrated a cytotoxicity that is selective to ERa-positive breast
    cancer cells (MCF-7), but not to ERa-negative breast cancer cells (MDA-MB-231) and to the control cells (MCF-
    10A). The objective of this study was to test the hypothesis that aloe emodin may enhance the response of
    MCF-7 cells to treatment with tamoxifen. MCF-7 cells were treated with aloe emodin alone, tamoxifen alone
    or a combination of emodin and tamoxifen, at their respective IC50 concentrations and at different time points
    of 24 hours, 48 hours and 72 hours. The respective IC50s were the concentrations of aloe emodin and tamoxifen
    required to achieve 50% inhibition of the cells in the study. Cell viability and apoptosis were determined using
    trypan blue exclusion and DNA fragmentation assays, respectively. The involvement of RAS/MEKs/ERKs genes
    of MAPK signalling pathways with aloe emodin was determined using QuantiGene 2.0 Plex assay. Data was
    evaluated using the one-way ANOVA test. Our findings showed that aloe emodin enhanced the cytotoxicity of
    tamoxifen on MCF-7 cells through apoptosis by downregulation of MEK1/2 genes. Our research may provide a
    rational basis for further in vivo studies to verify the efficacy of a combination of aloe emodin and tamoxifen
    on the viability of ERa-positive-breast cancer cells.
    Matched MeSH terms: Inhibitory Concentration 50
  8. Nipun TS, Khatib A, Ahmed QU, Redzwan IE, Ibrahim Z, Khan AYF, et al.
    Molecules, 2020 Sep 11;25(18).
    PMID: 32932994 DOI: 10.3390/molecules25184161
    The plant Psychotria malayana Jack belongs to the Rubiaceae family and is known in Malaysia as "meroyan sakat/salung". A rapid analytical technique to facilitate the evaluation of the P. malayana leaves' quality has not been well-established yet. This work aimed therefore to develop a validated analytical technique in order to predict the alpha-glucosidase inhibitory action (AGI) of P. malayana leaves, applying a Fourier Transform Infrared Spectroscopy (FTIR) fingerprint and utilizing an orthogonal partial least square (OPLS). The dried leaf extracts were prepared by sonication of different ratios of methanol-water solvent (0, 25, 50, 75, and 100% v/v) prior to the assessment of alpha-glucosidase inhibition (AGI) and the following infrared spectroscopy. The correlation between the biological activity and the spectral data was evaluated using multivariate data analysis (MVDA). The 100% methanol extract possessed the highest inhibitory activity against the alpha-glucosidase (IC50 2.83 ± 0.32 μg/mL). Different bioactive functional groups, including hydroxyl (O-H), alkenyl (C=C), methylene (C-H), carbonyl (C=O), and secondary amine (N-H) groups, were detected by the multivariate analysis. These functional groups actively induced the alpha-glucosidase inhibition effect. This finding demonstrated the spectrum profile of the FTIR for the natural herb P. malayana Jack, further confirming its medicinal value. The developed validated model can be used to predict the AGI of P. malayana, which will be useful as a tool in the plant's quality control.
    Matched MeSH terms: Inhibitory Concentration 50
  9. Kia Y, Osman H, Kumar RS, Murugaiyah V, Basiri A, Khaw KY, et al.
    Med Chem, 2014;10(5):512-20.
    PMID: 24138113
    A series of hitherto unreported piperidone embedded α,β-unsaturated ketones were synthesized efficiently in ionic solvent and evaluated for cholinesterase inhibitory activities against acetylcholinesterase (AChE) and butyrylcholinesterase (BChE) enzymes. Most of the synthesized compounds displayed good enzyme inhibition; therein compounds 7i and 7f displayed significant activity against AChE with IC50 values of 1.47 and 1.74 µM, respectively. Compound 6g showed the highest BChE inhibitory potency with IC50 value of 3.41 µM, being 5 times more potent than galanthamine. Molecular modeling simulation was performed using AChE and BChE receptors extracted from crystal structure of human AChE and human BChE to determine the amino acid residues involved in the binding interaction of synthesized compounds and their relevant receptors.
    Matched MeSH terms: Inhibitory Concentration 50
  10. Shukor MY, Masdor N, Baharom NA, Jamal JA, Abdullah MP, Shamaan NA, et al.
    Appl Biochem Biotechnol, 2008 Mar;144(3):283-91.
    PMID: 18556817
    A heavy-metal assay has been developed using bromelain, a protease. The enzyme is assayed using casein as a substrate with Coomassie dye to track completion of hydrolysis of casein. In the absence of inhibitors, casein is hydrolysed to completion, and the solution is brown. In the presence of metal ions such as Hg2+ and Cu2+, the hydrolysis of casein is inhibited, and the solution remains blue. Exclusion of sulfhydryl protective agent and ethylenediaminetetraacetic in the original assay improved sensitivity to heavy metals several fold. The assay is sensitive to Hg2+ and Cu2+, exhibiting a dose-response curve with an IC50 of 0.15 mg 1(-1) for Hg2+ and a one-phase binding curve with an IC50 of 0.23 mg 1(-1) for Cu2+. The IC50 value for Hg2+ is found to be lower to several other assays such as immobilized urease and papain assay, whilst the IC50 value for Cu2+ is lower than immobilized urease, 15-min Microtox, and rainbow trout.
    Matched MeSH terms: Inhibitory Concentration 50
  11. Manikam SD, Manikam ST, Stanslas J
    J Pharm Pharmacol, 2009 Jan;61(1):69-78.
    PMID: 19126299 DOI: 10.1211/jpp/61.01.0010
    The growth inhibiting potential of andrographolide was evaluated in three acute promyelocytic leukaemia cell line models (HL-60, NB4 and all-trans retinoic acid (ATRA)-resistant NB4-R2).
    Matched MeSH terms: Inhibitory Concentration 50
  12. Yeo SK, Liong MT
    Int J Food Sci Nutr, 2010 Mar;61(2):161-81.
    PMID: 20085504 DOI: 10.3109/09637480903348122
    Lactobacillus sp. FTDC 2113, L. acidophilus FTDC 8033, L. acidophilus ATCC 4356, L. casei ATCC 393, Bifidobacterium FTDC 8943 and B. longum FTDC 8643 were incorporated into soymilk supplemented with fructooligosaccharides (FOS), inulin, mannitol, maltodextrin and pectin. The objective of the present study was to evaluate the effects of prebiotics on the bioactivity of probiotic-fermented soymilk. Proteolytic activity was increased in the presence of FOS, while the supplementation of inulin and pectin increased the angiotensin I-converting enzyme inhibitory activity accompanied by lower IC(50) values. The beta-glucosidase activity was also enhanced in the presence of pectin. This led to higher bioconversion of glucosides to aglycones by probiotics, especially genistin and malonyl genistin to genistein. Results from this study indicated that the supplementation of prebiotics enhanced the in-vitro antihypertensive effect and production of bioactive aglycones in probiotic-fermented soymilk. Therefore, this soymilk could potentially be used as a dietary therapy to reduce the risks of hypertension and hormone-dependent diseases such as breast cancer, prostate cancer and osteoporosis.
    Matched MeSH terms: Inhibitory Concentration 50
  13. Ahmad F, Seerangan P, Mustafa MZ, Osman ZF, Abdullah JM, Idris Z
    Malays J Med Sci, 2019 Mar;26(2):30-39.
    PMID: 31447606 MyJurnal DOI: 10.21315/mjms2019.26.2.4
    Background: There has been increasing evidence showing that stingless bee honey exhibits anti-oxidant, anti-inflammatory and anti-cancer properties. Pharmacologically-active components in honey such as flavonoids and phenolic constituents are known to contribute to its medicinal benefits. To the best of our knowledge, this is the first study on evaluating anti-cancer effects of locally-produced Malaysian stingless bee honey from Heterotrigona itama sp. on malignant glioma cells.

    Methods: Proliferation and apoptosis studies of U-87 MG cells following stingless bee honey treatment were carried out using MTS assay and acridine orange/propidium iodide dual staining, respectively.

    Results: Results demonstrated time and dose-dependent cytotoxicity using 0.625%, 1.25% and 10% stingless bee honey (P < 0.05). IC50 values were calculated using cells treated with 10% stingless bee honey. It was also observed that 10% stingless bee honey induced nuclear shrinkage, chromatin condensation and nucleus fragmentation, indicating that cellular changes were consistent with the apoptotic characteristics of the cells.

    Conclusion: These data provide a good basis for further evaluation of the medicinal properties of stingless bee honey from Heterotrigona itama sp. This source of honey may serve as a potential therapy for malignant glioma.

    Matched MeSH terms: Inhibitory Concentration 50
  14. Zamani A, Mat Jusoh SA, Al-Jamal HA, Sul'ain MD, Johan MF
    Asian Pac J Cancer Prev, 2016 11 01;17(11):4857-4861.
    PMID: 28030911
    Background: Imatinib mesylate, a tyrosine kinase inhibitor specifically targeting the BCR/ABL fusion protein, induces hematological remission in patients with chronic myeloid leukemia (CML). However, the majority of CML patients treated with imatinib develop resistance with prolonged therapy. Dendrophthoe pentandra (L.) Miq. is a Malaysian mistletoe species that has been used as a traditional treatment for several ailments such as smallpox, ulcers, and cancers. Methods: We developed a resistant cell line (designated as K562R) by long-term co-culture of a BCR/ ABL positive CML cell line, K562, with imatinib mesylate. We then investigated the anti-proliferative effects of D. pentandra methanol extract on parental K562 and resistant K562R cells. Trypan blue exclusion assays were performed to determine the IC50 concentration; apoptosis and cell cycle analysis were conducted by flow cytometry. Results: D. pentandra extract had greater anti-proliferative effects towards K562R (IC50= 192 μg/mL) compared to K562 (500 μg/ mL) cells. Upon treatment with D. pentandra extract at the IC50. concentration: K562 but not K562R demonstrated increase in apoptosis and cell cycle arrest in the G2/M phase. Conclusion: D. pentandra methanol extract exerts potent anti-proliferative effect on BCR/ABL positive K562 cells.
    Matched MeSH terms: Inhibitory Concentration 50
  15. Widowati W, Ginting CN, Lister INE, Girsang E, Amalia A, Wibowo SHB, et al.
    Trop Life Sci Res, 2020 Oct;31(3):127-144.
    PMID: 33214860 DOI: 10.21315/tlsr2020.31.3.9
    Skin aging is a complex natural process characterised by gradual diminishment of structural integrity and physiological imbalance of the skin tissue. Since the oxidative stress is tightly corelated to the skin aging process, the usage of antioxidant may serve as favourable strategies for slowing down the skin aging process. Mangosteen is an important fruit commodity and its extract had been extensively studied and revealing various biological activities. Present study aimed to assess the antioxidant and antiaging activity of mangosteen peel extract (MPE) and its phytochemical compounds. MPE and its compounds were subjected to ferric reducing antioxidant power (FRAP), hydroperoxide (H2O2) scavenging, anti-collagenase, anti-elastase, anti-hyaluronidase and anti-tyrosinase assay. MPE has the highest FRAP 116.31 ± 0.60 μM Fe(II) μg-1 extract, IC50 of MPE on H2O2 scavenging activity was 54.61 μg mL-1. MPE also has the highest anti elastase activity at IC50 7.40 μg mL-1. Alpha-mangostin showed potent anti-collagenase activity (IC50 9.75 μg mL-1). While gamma-mangostin showed potent anti-hyaluronidase (IC50 23.85 μg mL-1) and anti-tyrosinase (IC50 50.35 μg mL-1). MPE and its compounds were evaluated in vitro for antioxidant and antiaging activities. Current findings may provide scientific evidence for possible usage of mangosteen extract and its compounds as antioxidant and antiaging agent.
    Matched MeSH terms: Inhibitory Concentration 50
  16. Nakisah MA, Ida Muryany MY, Fatimah H, Nor Fadilah R, Zalilawati MR, Khamsah S, et al.
    World J Microbiol Biotechnol, 2012 Mar;28(3):1237-44.
    PMID: 22805843 DOI: 10.1007/s11274-011-0927-8
    Crude methanol extracts of a marine sponge, Aaptos aaptos, collected from three different localities namely Kapas, Perhentian and Redang Islands, Terengganu, Malaysia, were tested in vitro on a pathogenic Acanthamoeba castellanii (IMR isolate) to examine their anti-amoebic potential. The examination of anti-Acanthamoebic activity of the extracts was conducted in 24 well plates for 72 h at 30 °C. All extracts possessed anti-amoebic activity with their IC(50) values ranging from 0.615 to 0.876 mg/mL. The effect of the methanol extracts on the surface morphology of A. castellanii was analysed under scanning electron microscopy. The ability of the extracts to disrupt the amoeba cell membrane was indicated by extensive cell's blebbing, changes in the surface morphology, reduced in cell size and with cystic appearance of extract-treated Acanthamoeba. Number of acanthapodia and food cup was also reduced in this Acanthamoeba. Morphological criteria of apoptosis in Acanthamoeba following treatment with the sponge's extracts was determined by acridine orange-propidium iodide staining and observed by fluorescence microscopy. By this technique, apoptotic and necrotic cells can be visualized and quantified. The genotoxic potential of the methanol extracts was performed by the alkaline comet assay. All methanol extracts used were significantly induced DNA damage compared to untreated Acanthamoeba by having high percentage of scores 1, 2, and 3 of the DNA damage. Results from cytotoxicity and genotoxicity studies carried out in the present study suggest that all methanol extracts of A. aaptos have anti-amoebic properties against A. castellanii.
    Matched MeSH terms: Inhibitory Concentration 50
  17. Ibrahim MA, Yusof MS, Amin NM
    Molecules, 2014 Apr 22;19(4):5191-204.
    PMID: 24759076 DOI: 10.3390/molecules19045191
    Thiourea derivatives display a broad spectrum of applications in chemistry, various industries, medicines and various other fields. Recently, different thiourea derivatives have been synthesized and explored for their anti-microbial properties. In this study, four carbonyl thiourea derivatives were synthesized and characterized, and then further tested for their anti-amoebic properties on two potential pathogenic species of Acanthamoeba, namely A. castellanii (CCAP 1501/2A) and A. polyphaga (CCAP 1501/3A). The results indicate that these newly-synthesized thiourea derivatives are active against both Acanthamoeba species. The IC50 values obtained were in the range of 2.39-8.77 µg·mL⁻¹ (9.47-30.46 µM) for A. castellanii and 3.74-9.30 µg·mL⁻¹ (14.84-31.91 µM) for A. polyphaga. Observations on the amoeba morphology indicated that the compounds caused the reduction of the amoeba size, shortening of their acanthopodia structures, and gave no distinct vacuolar and nuclear structures in the amoeba cells. Meanwhile, fluorescence microscopic observation using acridine orange and propidium iodide (AOPI) staining revealed that the synthesized compounds induced compromised-membrane in the amoeba cells. The results of this study proved that these new carbonyl thiourea derivatives, especially compounds M1 and M2 provide potent cytotoxic properties toward pathogenic Acanthamoeba to suggest that they can be developed as new anti-amoebic agents for the treatment of Acanthamoeba keratitis.
    Matched MeSH terms: Inhibitory Concentration 50
  18. Nor Azman NS, Hossan MS, Nissapatorn V, Uthaipibull C, Prommana P, Jin KT, et al.
    Exp Parasitol, 2018 Nov;194:67-78.
    PMID: 30268422 DOI: 10.1016/j.exppara.2018.09.020
    Treatment of drug resistant protozoa, bacteria, and viruses requires new drugs with alternative chemotypes. Such compounds could be found from Southeast Asian medicinal plants. The present study examines the cytotoxic, antileishmanial, and antiplasmodial effects of 11 ethnopharmacologically important plant species in Malaysia. Chloroform extracts were tested for their toxicity against MRC-5 cells and Leishmania donovani by MTT, and chloroquine-resistant Plasmodium falciparum K1 strain by Histidine-Rich Protein II ELISA assays. None of the extract tested was cytotoxic to MRC-5 cells. Extracts of Uvaria grandiflora, Chilocarpus costatus, Tabernaemontana peduncularis, and Leuconotis eugenifolius had good activities against L. donovani with IC50 50 μg/mL. Extracts of U. grandiflora, C. costatus, T. peduncularis, L. eugenifolius, A. subulatum, and C. aeruginosa had good activities against P. falciparum K1 with IC50 
    Matched MeSH terms: Inhibitory Concentration 50
  19. Ahmed S, Gul S, Idris F, Hussain A, Zia-Ul-Haq M, Jaafar HZ, et al.
    Molecules, 2014;19(8):11385-94.
    PMID: 25090125 DOI: 10.3390/molecules190811385
    Human plasma inhibits arachidonic acid metabolism and platelet aggregation. This helps human form a haemostatic control system that prevents the progress of certain aggregatory or inflammatory reactions. Whether this property of plasma is unique to human or extends to other species is not well known. It is speculated that this protective ability of plasma remains evolutionarily conserved in different mammals. In order to confirm this, the effect of plasma from 12 different mammalian species was investigated for its inhibitory potential against arachidonic acid metabolism and platelet aggregation. Metabolism of arachidonic acid by cyclooxygenase and lipoxygenase pathways was studies using radio-immuno assay and thin layer chromatography while platelet aggregation in the plasma of various mammals was monitored following turbedmetric method in a dual channel aggregometer. Results indicate that inhibition of AA metabolism and platelet aggregation is a common feature of plasma obtained from different mammalian species, although there exists large interspecies variation. This shows that besides human, other mammals also possess general protective mechanisms against various aggregatory and inflammatory conditions and this anti-inflammatory property of the plasma is evolutionarily conserved in mammalian species. The most likely candidates responsible for these properties of plasma include haptoglobin, albumin and lipoproteins.
    Matched MeSH terms: Inhibitory Concentration 50
  20. Dahari DE, Salleh RM, Mahmud F, Chin LP, Embi N, Sidek HM
    Trop Life Sci Res, 2016 Aug;27(2):53-71.
    PMID: 27688851 MyJurnal DOI: 10.21315/tlsr2016.27.2.5
    Exploiting natural resources for bioactive compounds is an attractive drug discovery strategy in search for new anti-malarial drugs with novel modes of action. Initial screening efforts in our laboratory revealed two preparations of soil-derived actinomycetes (H11809 and FH025) with potent anti-malarial activities. Both crude extracts showed glycogen synthase kinase 3β (GSK3β)-inhibitory activities in a yeast-based kinase assay. We have previously shown that the GSK3 inhibitor, lithium chloride (LiCl), was able to suppress parasitaemia development in a rodent model of malarial infection. The present study aims to evaluate whether anti-malarial activities of H11809 and FH025 involve the inhibition of GSK3β. The acetone crude extracts of H11809 and FH025 each exerted strong inhibition on the growth of Plasmodium falciparum 3D7 in vitro with 50% inhibitory concentration (IC50) values of 0.57 ± 0.09 and 1.28 ± 0.11 µg/mL, respectively. The tested extracts exhibited Selectivity Index (SI) values exceeding 10 for the 3D7 strain. Both H11809 and FH025 showed dosage-dependent chemo-suppressive activities in vivo and improved animal survivability compared to non-treated infected mice. Western analysis revealed increased phosphorylation of serine (Ser 9) GSK3β (by 6.79 to 6.83-fold) in liver samples from infected mice treated with H11809 or FH025 compared to samples from non-infected or non-treated infected mice. A compound already identified in H11809 (data not shown), dibutyl phthalate (DBP) showed active anti-plasmodial activity against 3D7 (IC50 4.87 ± 1.26 µg/mL which is equivalent to 17.50 µM) and good chemo-suppressive activity in vivo (60.80% chemo-suppression at 300 mg/kg body weight [bw] dosage). DBP administration also resulted in increased phosphorylation of Ser 9 GSK3β compared to controls. Findings from the present study demonstrate that the potent anti-malarial activities of H11809 and FH025 were mediated via inhibition of host GSK3β. In addition, our study suggests that DBP is in part the bioactive component contributing to the anti-malarial activity displayed by H11809 acting through the inhibition of GSK3β.
    Matched MeSH terms: Inhibitory Concentration 50
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