Displaying all 11 publications

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  1. Lee CBTL, Wu TY, Ting CH, Tan JK, Siow LF, Cheng CK, et al.
    Bioresour Technol, 2019 Apr;278:486-489.
    PMID: 30711220 DOI: 10.1016/j.biortech.2018.12.034
    The performances of various anhydrous and aqueous choline chloride-dicarboxylic acid based deep eutectic solvents (DESs) were evaluated for furfural production from oil palm fronds without any additional catalyst. The effects of different carbon chain length dicarboxylic acids and water content in each DES on furfural production were investigated. Oil palm fronds, DES and water (0-5 ml) were mixed and reacted in an oil bath (60-300 min). Reacted oil palm fronds had the potential to be reused as cellulose-rich-valuable by-products. At 100 °C, aqueous choline chloride-oxalic acid (16.4 wt% H2O) produced the highest furfural yield of 26.34% and cellulose composition up to 72.79% in the reacted oil palm fronds. Despite operating at suitable reaction duration for dicarboxylic acid with longer carbon chain length, aqueous choline chloride-malonic acid and aqueous choline chloride-succinic acid performed poorly with furfural yield of less than 1%.
    Matched MeSH terms: Carboxylic Acids/chemistry*
  2. Azmi MN, Gény C, Leverrier A, Litaudon M, Dumontet V, Birlirakis N, et al.
    Molecules, 2014;19(2):1732-47.
    PMID: 24492595 DOI: 10.3390/molecules19021732
    A phytochemical investigation of the methanolic extract of the bark of Endiandra kingiana led to the isolation of seven new tetracyclic endiandric acid analogues, kingianic acids A-G (1-7), together with endiandric acid M (8), tsangibeilin B (9) and endiandric acid (10). Their structures were determined by 1D- and 2D-NMR analysis in combination with HRMS experiments. The structure of compounds 9 and 10 were confirmed by single-crystal X-ray diffraction analysis. These compounds were screened for Bcl-xL and Mcl-1 binding affinities and cytotoxic activity on various cancer cell lines. Compound 5 showed moderate cytotoxic activity against human colorectal adeno-carcinoma (HT-29) and lung adenocarcinoma epithelial (A549) cell lines, with IC50 values in the range 15-17 µM, and compounds 3, 6 and 9 exhibited weak binding affinity for the anti-apoptotic protein Mcl-1.
    Matched MeSH terms: Carboxylic Acids/chemistry*
  3. Khalil MI, Alam N, Moniruzzaman M, Sulaiman SA, Gan SH
    J Food Sci, 2011 Aug;76(6):C921-8.
    PMID: 22417491 DOI: 10.1111/j.1750-3841.2011.02282.x
    The phenolic acid and flavonoid contents of Malaysian Tualang, Gelam, and Borneo tropical honeys were compared to those of Manuka honey. Ferric reducing/antioxidant power assay (FRAP) and the 1,1-diphenyl-2-picryl-hydrazyl (DPPH) radical-scavenging activities were also quantified. All honey extracts exhibited high phenolic contents (15.21 ± 0.51- 42.23 ± 0.64 mg/kg), flavonoid contents (11.52 ± 0.27- 25.31 ± 0.37 mg/kg), FRAP values (892.15 ± 4.97- 363.38 ± 10.57 μM Fe[II]/kg), and high IC₅₀ of DPPH radical-scavenging activities (5.24 ± 0.40- 17.51 ± 0.51 mg/mL). Total of 6 phenolic acids (gallic, syringic, benzoic, trans-cinnamic, p-coumaric, and caffeic acids) and 5 flavonoids (catechin, kaempferol, naringenin, luteolin, and apigenin) were identified. Among the Malaysian honey samples, Tualang honey had the highest contents of phenolics, and flavonoids, and DPPH radical-scavenging activities. We conclude that among Malaysian honey samples, Tualang honey is the richest in phenolic acids, and flavonoid compounds, which have strong free radical-scavenging activities.
    Matched MeSH terms: Carboxylic Acids/chemistry
  4. Kamaruddin AH, Uzir MH, Aboul-Enein HY, Halim HN
    Chirality, 2009 Apr;21(4):449-67.
    PMID: 18655180 DOI: 10.1002/chir.20619
    This review tracks a decade of dynamic kinetic resolution developments with a biocatalytic inclination using enzymatic/microbial means for the resolution part followed by the racemization reactions either by means of enzymatic or chemocatalyst. These fast developments are due to the ability of the biocatalysts to significantly reduce the number of synthetic steps which are common for conventional synthesis. Future developments in novel reactions and products of dynamic kinetic resolutions should consider factors that are needed to be extracted at the early synthetic stage to avoid inhibition at scale-up stage have been highlighted.
    Matched MeSH terms: Carboxylic Acids/chemistry
  5. Moniruzzaman M, Rodríguez I, Ramil M, Cela R, Sulaiman SA, Gan SH
    Talanta, 2014 Nov;129:505-15.
    PMID: 25127626 DOI: 10.1016/j.talanta.2014.06.019
    The performance of gas chromatography (GC) combined with a hybrid quadrupole time-of-flight (QTOF) mass spectrometry (MS) system for the determination of volatile and semi-volatile compounds in honey samples is evaluated. After headspace (HS) solid-phase microextraction (SPME) of samples, the accurate mass capabilities of the above system were evaluated for compounds identification. Accurate scan electron impact (EI) MS spectra allowed discriminating compounds displaying the same nominal masses, but having different empirical formulae. Moreover, the use of a mass window with a width of 0.005 Da provided highly specific chromatograms for selected ions, avoiding the contribution of interferences to their peak areas. Additional information derived from positive chemical ionization (PCI) MS spectra and ion product scan MS/MS spectra permitted confirming the identity of novel compounds. The above possibilities are illustrated with examples of honey aroma compounds, belonging to different chemical classes and containing different elements in their molecules. Examples of compounds whose structures could not be described are also provided. Overall, 84 compounds, from a total of 89 species, could be identified in 19 honey samples from 3 different geographic areas in the world. The suitability of responses measured for selected ions, corresponding to above species, for authentication purposes is assessed through principal components analysis.
    Matched MeSH terms: Carboxylic Acids/chemistry
  6. Salar U, Khan KM, Taha M, Ismail NH, Ali B, Qurat-Ul-Ain, et al.
    Eur J Med Chem, 2017 Jan 05;125:1289-1299.
    PMID: 27886546 DOI: 10.1016/j.ejmech.2016.11.031
    Current study is based on the biology-oriented drug synthesis (BIODS) of 2-(2-methyl-5-nitro-1H-imidazol-1-yl)ethyl aryl carboxylate derivatives 1-26, by treating metronidazole with different aryl and hetero-aryl carboxylic acids in the presence of 1,1'-carbonyl diimidazole (CDI) as a coupling agent. Structures of all synthetic derivatives were confirmed with the help of various spectroscopic techniques such as EI-MS, (1)H -NMR and (13)C NMR. CHN elemental analyses were also found in agreement with the calculated values. Synthetic derivatives were evaluated to check their β-glucuronidase inhibitory activity which revealed that except few derivatives, all demonstrated good inhibition in the range of IC50 = 1.20 ± 0.01-60.30 ± 1.40 μM as compared to the standard d-saccharic acid 1,4-lactone (IC50 = 48.38 ± 1.05 μM). Compounds 1, 3, 4, 6, 9-19, and 21-24 were found to be potent analogs and showed superior activity than standard. Limited structure-activity relationship is suggested that the molecules having electron withdrawing groups like NO2, F, Cl, and Br, were displayed better activity than the compounds with electron donating groups such as Me, OMe and BuO. To verify these interpretations, in silico study was also performed, a good correlation was observed between bioactivities and docking studies.
    Matched MeSH terms: Carboxylic Acids/chemistry
  7. Dige NC, Mahajan PG, Raza H, Hassan M, Vanjare BD, Hong H, et al.
    Bioorg Chem, 2020 07;100:103906.
    PMID: 32422387 DOI: 10.1016/j.bioorg.2020.103906
    A new series of 4H-chromene-3-carboxylate derivatives were synthesized using multicomponent reaction of salicylaldehyde, ethyl acetoacetate and dimedone in ethanol with K3PO4 as a catalyst at 80 °C. The structures of all newly synthesized compounds were confirmed by spectral techniques viz. IR, 1H NMR, 13C NMR, and LCMS analysis. The newly synthesized compounds 4a to 4j were screened against elastase enzyme. Interestingly, all these compounds found to be potent elastase inhibitors with much lower IC50 value. The compound 4b was found to be most potent elastase inhibitor (IC50 = 0.41 ± 0.01 µM) amongst the synthesized series against standard Oleanolic Acid (IC50 value = 13.45 ± 0.0 µM). The Kinetics mechanism for compound 4b was analyzed by Lineweaver-Burk plots which revealed that compound inhibited elastase competitively by forming an enzyme-inhibitor complex. Along with this, all the synthesized compounds (4a - 4j) exhibits excellent DPPH free radical scavenging ability. The inhibition constant Ki for compound 4b was found to be 0.6 µM. The computational study was comprehensible with the experimental results with good docking energy values (Kcal/mol). Therefore, these molecules can be considered as promising medicinal scaffolds for the treatment of skin-related maladies.
    Matched MeSH terms: Carboxylic Acids/chemistry
  8. van der Sar SA, Blunt JW, Cole AL, Din LB, Munro MH
    J Nat Prod, 2005 Dec;68(12):1799-801.
    PMID: 16378381
    A new dichlorinated pulvinic acid derivative, methyl-3',5'-dichloro-4,4'-di-O-methylatromentate, was isolated from the fruiting body of a Scleroderma sp. The structure was determined using spectroscopic methods, and an X-ray analysis was carried out for confirmation of the structure. Compound was found to display moderate antimicrobial activity against Bacillus subtilis.
    Matched MeSH terms: Carboxylic Acids/chemistry
  9. Saeedfar K, Heng LY, Chiang CP
    Bioelectrochemistry, 2017 Dec;118:106-113.
    PMID: 28780443 DOI: 10.1016/j.bioelechem.2017.07.012
    Multi-wall carbon nanotubes (MWCNTs) were modified to design a new DNA biosensor. Functionalized MWCNTs were equipped with gold nanoparticles (GNPs) (~15nm) (GNP-MWCNTCOOH) to construct DNA biosensors based on carbon-paste screen-printed (SPE) electrodes. GNP attachment onto functionalized MWCNTs was carried out by microwave irradiation and was confirmed by spectroscopic studies and surface analysis. DNA biosensors based on differential pulse voltammetry (DPV) were constructed by immobilizing thiolated single-stranded DNA probes onto GNP-MWCNTCOOH. Ruthenium (III) chloride hexaammoniate [Ru(NH3)6,2Cl(-)] (RuHex) was used as hybridization redox indicator. RuHex and MWCNT interaction was low in compared to other organic redox hybridization indicators. The linear response range for DNA determination was 1×10(-21) to 1×10(-9)M with a lower detection limit of 1.55×10(-21)M. Thus, the attachment of GNPs onto functionalized MWCNTs yielded sensitive DNA biosensor with low detection limit and stability more than 30days. Constructed electrode was used to determine gender of arowana fish.
    Matched MeSH terms: Carboxylic Acids/chemistry
  10. Lee WH, Loo CY, Rohanizadeh R
    Mater Sci Eng C Mater Biol Appl, 2019 Jun;99:929-939.
    PMID: 30889767 DOI: 10.1016/j.msec.2019.02.030
    This study has evaluated the effect of functionalizing surface charges of hydroxyapatite on the modulation of loading and release of curcumin nanoparticles. The increase in loading and release of curcumin nanoparticles indirectly translates to enhanced anti-cancer effect. Owing to the hydrophobic characteristics of curcumin which have resulted in low bioavailability in cancer cells, the engineering curcumin into nanoparticles is therefore a viable solution to overcomes its limitation. In order to maintain a sustained release profile of curcumin nanoparticles, curcumin nanoparticles were loaded (Cur-NPs) onto hydroxyapatite (HA) via physical adsorption. To regulate the adsorption capacity of Cur-NPs onto HA, we functionalized HA with different carboxylic acids (lactic acid, tartaric acid and citric acid). The presence of carboxylic groups on HA significantly affected the binding and the release profile of Cur-NPs. The effects of Cur-NPs loaded HA were evaluated on breast cancer cell line (MCF-7), which included cell proliferation, cellular uptake of Cur-NPs, apoptosis and cell cycle analysis. The results showed that carboxylic acid-functionalized HA demonstrated higher anti-proliferating activity and time dependent cytoplasmic uptake of Cur-NPs in MCF-7 cells compared to unmodified HA. In addition, Cur-NPs loaded on functionalized HA induced higher apoptosis and cell cycle arrest in MCF-7 cells compared to unmodified HA. The present study indicates that the delivery of Cur-NPs to breast cancer using carboxylic acid-functionalized HA carrier could improve their anti-cancer activities.
    Matched MeSH terms: Carboxylic Acids/chemistry*
  11. Hasanpourghadi M, Pandurangan AK, Karthikeyan C, Trivedi P, Mustafa MR
    Oncotarget, 2017 Apr 25;8(17):28840-28853.
    PMID: 28392503 DOI: 10.18632/oncotarget.16263
    Microtubule Targeting Agents (MTAs) induce cell death through mitotic arrest, preferentially affecting rapidly dividing cancer cells over slowly proliferating normal cells. Previously, we showed that Methyl 2-(-5-fluoro-2-hydroxyphenyl)-1H-benzo[d]imidazole-5-carboxylate (MBIC) acts as a potential MTA. In this study, we demonstrated that MBIC exhibits greater toxicity towards non-aggressive breast cancer cell-line, MCF-7 (IC50 = 0.73 ± 0.0 μM) compared to normal fibroblast cell-line, L-cells (IC50 = 59.6 ± 2.5 μM). The IC50 of MBIC against the aggressive breast cancer cell-line, MDA-MB-231 was 20.4 ± 0.2 μM. We hypothesized that the relatively high resistance of MDA-MB-231 cells to MBIC is associated with p53 mutation. We investigated p53 and three of its downstream proteins: survivin, cyclin dependent kinase (Cdk1) and cyclin B1. Following treatment with MBIC, survivin co-immunoprecipitated with caspases with higher affinity in MDA-MB-231 compared to MCF-7 cells. Furthermore, silencing survivin caused a 4.5-fold increase in sensitivity of MDA-MB-231 cells to MBIC (IC50 = 4.4 ± 0.3). In addition, 4 weeks of MBIC administration in MDA-MB-231 cells inoculated BALB/c nude mice resulted in 79.7% reduction of tumor volume compared to the untreated group with no severe sign of toxicity. Our results demonstrated MBIC has multiple anti-tumor actions and could be a potential drug in breast cancer therapy.
    Matched MeSH terms: Carboxylic Acids/chemistry
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