Displaying publications 1 - 20 of 164 in total

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  1. Hasan N, Osman H, Mohamad S, Chong WK, Awang K, Zahariluddin AS
    Pharmaceuticals (Basel), 2012;5(8):882-9.
    PMID: 24280680 DOI: 10.3390/ph5080882
    Three isoflavanoids, isovestitol (1), medicarpin (2), and sativan (3), along with another known compound, betulinic acid (4), were isolated from the root of Sesbania grandiflora. The structures of the isolated compounds were characterised by means of spectroscopic techniques (UV, IR, MS, 1H- and 13C-NMR, DEPT, COSY, HMQC, HMBC, and MS analysis). All the tested compounds 1-4 exhibited antituberculosis activity against Mycobacterium tuberculosis H37Rv, with MIC values of 50 µg/mL for compounds 1-3, and 100 µg/mL for compound 4, whereas, the methanol extract exhibited antituberculosis activity of 625 µg/mL. This is the first report on the occurrence of isoflavonoids in this plant and their antituberculosis activity.
  2. Velu SS, Buniyamin I, Ching LK, Feroz F, Noorbatcha I, Gee LC, et al.
    Chemistry, 2008;14(36):11376-84.
    PMID: 19003831 DOI: 10.1002/chem.200801575
    Oligostilbenoids are polyphenols that are widely distributed in nature with multifaceted biological activities. To achieve biomimetic synthesis of unnatural derivatives, we subjected three resveratrol analogues to oligomerization by means of one-electron oxidants. Upon varying the metal oxidant (AgOAc, CuBr(2), FeCl(3)6 H(2)O, FeCl(3)6 H(2)O/NaI, PbO(2), VOF(3)), the solvent (over the whole range of polarities), and the oxygenated substitution pattern of the starting material, stilbenoid oligomers with totally different carbon skeletons were obtained. Here we propose to explain the determinism of the type of skeleton produced with the aid of hard and soft acid/base concepts in conjunction with the solvating properties of the solvents and the preferred alignment by the effect of pi stacking.
  3. Ambikabothy J, Ibrahim H, Ambu S, Chakravarthi S, Awang K, Vejayan J
    J Ethnopharmacol, 2011 Sep 1;137(1):257-62.
    PMID: 21640180 DOI: 10.1016/j.jep.2011.05.013
    Evaluations of the anti-snake venom efficacy of Mimosa pudica tannin isolate (MPT) obtained from root of the plant.
  4. Kee CH, Ariffin A, Awang K, Noorbatcha I, Takeya K, Morita H, et al.
    Molecules, 2011 Aug 25;16(9):7267-87.
    PMID: 21869754 DOI: 10.3390/molecules16097267
    The n-butyramido, isobutyramido, benzamido, and furancarboxamido functions profoundly modulate the electronics of the stilbene olefinic and NH groups and the corresponding radical cations in ways that influence the efficiency of the cyclization due presumably to conformational and stereoelectronic factors. For example, isobutyramido- stilbene undergoes FeCl(3) promoted cyclization to produce only indoline, while n-butyramidostilbene, under the same conditions, produces both indoline and bisindoline.
  5. Kee CH, Ariffin A, Awang K, Takeya K, Morita H, Hussain SI, et al.
    Org Biomol Chem, 2010 Dec 21;8(24):5646-60.
    PMID: 20941451 DOI: 10.1039/c0ob00296h
    The syntheses of fourteen unusual o-carboxamido stilbenes by the Heck protocol revealed surprising complexity related to intriguing substituent effects with mechanistic implications. The unexpected cytotoxic and chemopreventive properties also seem to be substituent dependent. For example, although stilbene 15d (with a 4-methoxy substituent) showed cytotoxicity on HT29 colon cancer cells with an IC(50) of 4.9 μM, the 3,4-dimethoxy derivative (15c) is inactive. It is interesting to observe that the 3,5-dimethoxy derivative (15e) showed remarkable chemopreventive activity in WRL-68 fetal hepatocytes, surpassing the gold standard, resveratrol. The resveratrol concentration needed to be 5 times higher than that of 15e to produce comparable elevation of NQO1.
  6. Awang K, Abdullah Z, Mukhtar MR, Litaudon M, Jaafar FM, Hadi AH, et al.
    Nat Prod Res, 2009;23(7):652-8.
    PMID: 19401920 DOI: 10.1080/14786410802323743
    Dunaliine A (1), a new amino diketone, has been isolated from the leaves of Desmos dunalii together with four known dihydrochalcones: 2',4-dihydroxy-4',6'-dimethoxy-3',5'-dimethyldihydrochalcone (2), 2',4-dihydroxy-4',6'-dimethoxydihydrochalcone (3), 2',4-dihydroxy-4',5',6'-trimethoxydihydrochalcone (4) and 2',4-dihydroxy-5'-methyl-4',6'-dimethoxydihydrochalcone (5). The structures of these compounds were established notably by spectral analysis (1D- and 2D- (1)H, (13)C NMR), UV, IR and HRMS.
  7. Murtihapsari M, Salam S, Kurnia D, Darwati D, Kadarusman K, Abdullah FF, et al.
    Nat Prod Res, 2021 Mar;35(6):937-944.
    PMID: 31210054 DOI: 10.1080/14786419.2019.1611815
    A new antimalarial sterol, kaimanol (1), along with a known sterol, saringosterol (2) was isolated from the Indonesian Marine sponge, Xestospongia sp. The chemical structure of the new compound was determined on the basis of spectroscopic evidences and by comparison to those related compounds previously reported. Isolated compounds, 1 and 2 were evaluated for their antiplasmodial effect against Plasmodium falciparum 3D7 strains. Compounds 1 and 2 exhibited antiplasmodial activity with IC50 values of 359 and 0.250 nM, respectively.
  8. Leong KH, Mahdzir MA, Din MF, Awang K, Tanaka Y, Kulkeaw K, et al.
    Phytomedicine, 2017 Mar 15;26:11-21.
    PMID: 28257660 DOI: 10.1016/j.phymed.2016.12.018
    BACKGROUND: Leukaemia stem cells (LSC) have been associated with disease relapse and chemotherapy resistance. Betulonic acid (BA), a pentacyclic lupane-type triterpenoid, was reported to exhibit cytotoxicity toward various cancer cells and to be capable of inducing intrinsic apoptosis in solid tumours. However, the in vitro and in vivo apoptotic effects of BA against LSC remain unknown.

    HYPOTHESIS/PURPOSE: We aimed to determine whether BA isolated from bark of Walsura pinnata Hassk (Meliaceae) has pro-apoptotic effects on LSC in in vitro and in vivo models.

    STUDY DESIGN/METHODS: The population of high purity LSC was isolated from the Kasumi-1 cell line using magnetic sorting and characterised by flow cytometry. Cell viability was assessed using the MTS assay to examine dose- and time-dependent effects. The colony formation assay was performed in MethoCult® H4435 enriched media. Apoptosis was analysed using Annexin-V and propidium iodide staining, mitochondrial transmembrane potential was studied using JC-1 staining, and expression of apoptosis related genes (BAX, Bcl-2 and survivin) was evaluated by real time-polymerase chain reaction (RT-PCR). Caspase 3/7 and 9 activities were monitored through Promega Caspase-Glo® over a period of 24h. The in vivo antileukaemia activity was evaluated using LSC xenotransplanted zebrafish, observed for DNA fragmentation from apoptosis by TUNEL assay.

    RESULTS: BA maintained its potency against the LSC population in comparison to parental Kasumi-1 cells (fold differences ≤ 1.94) over various treatment time points and significantly inhibited the formation of colonies by LSC. Apoptosis was triggered by BA through the upregulation of BAX and suppression of Bcl-2 and survivin genes with the loss of mitochondrial transmembrane potential, leading to the activation of caspase 9 followed by downstream caspase 3/7. BA was able to suppressed leukaemia formation and induced apoptosis in LSC xenotransplanted zebrafish.

    CONCLUSIONS: The results demonstrate that BA inhibited the proliferative and colonogenic properties of LSC. BA induced apoptosis in LSC through the mitochondria pathway and was effective in the in vivo zebrafish model. Therefore, BA could be a lead compound for further development into a chemotherapy agent against LSC.

  9. Kadir R, Awang K, Khamaruddin Z, Soit Z
    An Acad Bras Cienc, 2015 Apr-Jun;87(2):743-51.
    PMID: 26131633 DOI: 10.1590/0001-3765201520140041
    Wood extractives from heartwood of Callophylum inophyllum (bintangor) were obtained by shaker method and analyzed for their constituents by gas chromatography-mass spectrometry (GC-MS). Ten compounds were identified by ethanol (EtOH) solvents, fourteen by methanol (MeOH) and only nine by petroleum ether (PETETHR). Major compounds were contributed by monoterpenes (75.11%, 53.75%) when extracted with EtOH and PETETHR solvents. The anti-termitic assay of the wood extracts was also investigated against Coptotermes curvignathus. The level of concentration for anti-termite activity may be an indication of the dose application of the wood extracts for new development of termiticide.
  10. Hutagaol RP, Harneti D, Safari A, Hidayat AT, Supratman U, Awang K, et al.
    J Asian Nat Prod Res, 2021 Aug;23(8):781-788.
    PMID: 32536210 DOI: 10.1080/10286020.2020.1776704
    A seco-apotirucallane-type triterpenoid, namely angustifolianin (1), along with three dammarane-type triterpenoids, (20S, 24S)-epoxy-dammarane-3β,25-diol (2), 3-epi-cabraleahydroxylactone (3), and cabralealactone (4), were isolated from the stem bark of Aglaia angustifolia Miq. The Chemical structure of the new compounds was elucidated on the basis of spectroscopic data. All of the compounds were evaluated for their cytotoxic effects against MCF-7 breast cancer cells. Among those compounds, angustifolianin (1) showed strongest cytotoxic activity with an IC50 value of 50.5 μg/ml.
  11. Islam MK, Biswas NN, Saha S, Hossain H, Jahan IA, Khan TA, et al.
    ScientificWorldJournal, 2014;2014:869537.
    PMID: 24707219 DOI: 10.1155/2014/869537
    Different parts of the medicinal plant Zanthoxylum budrunga Wall enjoy a variety of uses in ethnobotanical practice in Bangladesh. In the present study, a number of phytochemical and pharmacological investigations were done on the ethanol extract of Z. budrunga seeds (ZBSE) to evaluate its antinociceptive and antioxidant potential. ZBSE was also subjected to HPLC analysis to detect the presence of some common antioxidants. In acetic acid induced writhing test in mice, ZBSE showed 65.28 and 74.30% inhibition of writhing at the doses of 250 and 500 mg/kg and the results were statistically significant (P < 0.001). In hot-plate test, ZBSE raised the pain threshold significantly (P < 0.001) throughout the entire observation period. In DPPH scavenging assay, the IC50 of ZBSE was observed at 82.60 μg/mL. The phenolic content was found to be 338.77 mg GAE/100 g of dried plant material. In reducing power assay, ZBSE showed a concentration dependent reducing ability. HPLC analysis indicated the presence of caffeic acid with a concentration of 75.45 mg/100 g ZBSE. Present investigation supported the use of Zanthoxylum budrunga seed in traditional medicine for pain management. Constituents including caffeic acid and other phenolics might have some role in the observed activity.
  12. Islam MK, Saha S, Mahmud I, Mohamad K, Awang K, Jamal Uddin S, et al.
    J Ethnopharmacol, 2014 Feb 3;151(2):921-30.
    PMID: 24342778 DOI: 10.1016/j.jep.2013.11.056
    Madhupur forest area, Tangail is one of early human settlements in Bangladesh. Having abode in the vicinity of the forest, a strong ethnobotanical practice has prevailed in this area since ancient time. Due to the rapid deforestation during the last few decades, many plants have already disappeared or are facing extinction. Thus we attempted to document the medicinal plant use of Madhupur forest area with a view to preserve the ethnobotanical knowledge and in order to protect the biodiversity of this area.
  13. Gapil Tiamas S, Daressy F, Abou Samra A, Bignon J, Steinmetz V, Litaudon M, et al.
    Bioorg Med Chem Lett, 2020 04 01;30(7):127003.
    PMID: 32035700 DOI: 10.1016/j.bmcl.2020.127003
    A library of 26 novel carboxamides deriving from natural fislatifolic acid has been prepared. The synthetic strategy involved a bio-inspired Diels-Alder cycloaddition, followed by functionalisations of the carbonyl moiety. All the compounds were evaluated on Bcl-xL, Mcl-1 and Bcl-2 proteins. In this series of cyclohexenyl chalcone analogues, six compounds behaved as dual Bcl-xL/Mcl-1 inhibitors in micromolar range and one exhibited sub-micromolar affinities toward Mcl-1 and Bcl-2. The most potent compounds evaluated on A549 and MCF7 cancer cell lines showed moderate cytotoxicities.
  14. Rouger C, Derbré S, Charreau B, Pabois A, Cauchy T, Litaudon M, et al.
    J Nat Prod, 2015 Sep 25;78(9):2187-97.
    PMID: 26301802 DOI: 10.1021/acs.jnatprod.5b00222
    Phytochemical investigation on the fruits of Mesua lepidota (Calophyllaceae) led to the isolation of seven new phenylcoumarin derivatives named lepidotols A-E (1-5) and lepidotins A and B (6, 7). These structures were elucidated by spectroscopic and spectrometric methods including UV, NMR, and HRMS. Lepidotol A (1), the major compound, was evaluated for its inhibitory effect on inflammation and immunity using endothelial cell-based cellular assays. At 10 μM, 1 exhibited an anti-inflammatory activity, with a significant inhibition of vascular cell adhesion molecule 1 and intercellular adhesion molecule 1 expression induced by tumor necrosis factor-α. Lepidotol A also showed a mild immunosuppressive effect, with inhibition of the major histocompatibility complex molecules, namely, human leukocyte antigen (HLA)-DR and HLA-E.
  15. Bruguière A, Derbré S, Coste C, Le Bot M, Siegler B, Leong ST, et al.
    Fitoterapia, 2018 Nov;131:59-64.
    PMID: 30321650 DOI: 10.1016/j.fitote.2018.10.003
    Usually isolated from Garcinia (Clusiaceae) or Hypericum (Hypericaceae) species, some Polycyclic Polyprenylated AcylPhloroglucinols (PPAPs) have been recently reported as potential research tools for immunotherapy. Aiming at exploring the chemodiversity of PPAPs amongst Garcinia genus, a dereplication process suitable for such natural compounds has been developed. Although less sensitive than mass spectrometry, NMR spectroscopy is perfectly reproducible and allows stereoisomers distinction, justifying the development of 13C-NMR strategies. Dereplication requires the use of databases (DBs). To define if predicted DBs were accurate enough as dereplication tools, experimental and predicted δC of natural products usually isolated from Clusiaceae were compared. The ACD/Labs commercial software allowed to predict 73% of δC in a 1.25 ppm range around the experimental values. Consequently, with these parameters, the major PPAPs from a Garcinia bancana extract were successfully identified using a predicted DB.
  16. Wiart C, Martin MT, Awang K, Hue N, Serani L, Laprévote O, et al.
    Phytochemistry, 2001 Oct;58(4):653-6.
    PMID: 11576617
    A new sesquiterpene, scodopin, and a mixture of three tryptamine-type alkaloids, scorodocarpines A-C, were isolated from the fruits of Scorodocarpus borneensis, together with a known hemisynthetic sesquiterpene, cadalene-beta-carboxylic acid, which was isolated from the bark. The structures of the new compounds were elucidated by interpretation of spectral data, especially tandem mass spectrometry for the alkaloid mixture.
  17. Khan MA, Islam MK, Siraj MA, Saha S, Barman AK, Awang K, et al.
    PMID: 26025456 DOI: 10.1186/s13002-015-0033-3
    Garo Hills represents one of earliest human habitation in Bangladesh preserving its ancient cultures due to the geographic location. It is situated in the most northern part of Durgapur sub-district having border with Meghalaya of India. Durgapur is rich in ethnic diversity with Garo and Hajong as the major ethnic groups along with Bangalee settlers from the mainstream population. Thus the ethnomedicinal practice in Garo Hills is considered rich as it encompasses three different groups. Present survey was undertaken to compile the medicinal plant usage among the various communities of the Garo Hills.
  18. Levaique H, Pamlard O, Apel C, Bignon J, Arriola M, Kuhner R, et al.
    Molecules, 2021 Mar 11;26(6).
    PMID: 33799883 DOI: 10.3390/molecules26061551
    Leishmaniasis is a vector-borne disease caused by the protozoan parasite Leishmania found in tropical and sub-tropical areas, affecting 12 million people around the world. Only few treatments are available against this disease and all of them present issues of toxicity and/or resistance. In this context, the development of new antileishmanial drugs specifically directed against a therapeutic target appears to be a promising strategy. The GDP-Mannose Pyrophosphorylase (GDP-MP) has been previously shown to be an attractive therapeutic target in Leishmania. In this study, a chemical library of 5000 compounds was screened on both L. infantum (LiGDP-MP) and human (hGDP-MP) GDP-MPs. From this screening, oncostemonol D was found to be active on both GDP-MPs at the micromolar level. Ten alkyl-resorcinol derivatives, of which oncostemonols E and J (2 and 3) were described for the first time from nature, were then evaluated on both enzymes as well as on L. infantum axenic and intramacrophage amastigotes. From this evaluation, compounds 1 and 3 inhibited both GDP-MPs at the micromolar level, and compound 9 displayed a three-times lower IC50 on LiGDP-MP, at 11 µM, than on hGDP-MP. As they displayed mild activities on the parasite, these compounds need to be further pharmacomodulated in order to improve their affinity and specificity to the target as well as their antileishmanial activity.
  19. Mohamad K, Martin MT, Najdar H, Gaspard C, Sévenet T, Awang K, et al.
    J Nat Prod, 1999 Jun;62(6):868-72.
    PMID: 10395505
    Nine 3,4-secoapotirucallanes, argentinic acids A-I, were isolated from the bark of Aglaia argentea and transformed to their methyl esters 1-9. The structures were determined by spectral and chemical means. Compounds 1-8 showed moderate cytotoxic activity against KB cells (IC50 1.0-3.5 microg/mL).
  20. Alias Y, Awang K, Hadi AH, Thoison O, Sévenet T, Païs M
    J Nat Prod, 1995 Aug;58(8):1160-6.
    PMID: 7595585
    Bioassay-guided fractionation of an ethyl acetate extract of Fissistigma lanuginosum led to the isolation of the known chalcone pedicin [1], which inhibited tubulin assembly into microtubules (IC50 value of 300 microM). From the same EtOAc fraction, two new condensed chalcones, fissistin [2] and isofissistin [3], which showed cytotoxicity against KB cells, were also obtained, together with the inactive dihydropedicin [4] and 6,7-dimethoxy-5,8-dihydroxyflavone [5]. In addition, the aminoquinones 6, 8, and 9 were isolated from the alkaloid extract. These compounds were artifacts, prepared by treatment of 1, 4, and 2, respectively, with NH4OH. The structures of the new compounds were elucidated by spectral methods, especially 2D nmr.
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