Displaying publications 141 - 151 of 151 in total

Abstract:
Sort:
  1. High performance liquid chromatography (HPLC) method for confirming thin layer chromatography (TLC) findings in inborn errors of metabolism children in Malaysia
    Yahya NA, Ismail Z, Embong KH, Mohamad SA
    Southeast Asian J. Trop. Med. Public Health, 1995;26 Suppl 1:130-3.
    PMID: 8629091
    High performance liquid chromatography (HPLC) with phenylisothiocyanate (PITC) is recently used for confirming the diagnosis of inborn errors of metabolism (IEM) especially amino acid disorders in Malaysian children. The method of HPLC used is a precolumn derivatization of amino acids with phenylisothiocyanate and is separated by reversed phase chromatography using 3.9 x 300 mm free amino acid columns and is detected by a UV/Vis detector. The samples are obtained from cases suspected of inborn errors of metabolism, especially of amino acid disorders, which are detected clinically by pediatricians. Initially, samples from patients suspected of inborn errors of metabolism, either urine or serum, are run on one-dimensional thin layer chromatography and supplementary chemical tests to detect the abnormal bands and associated abnormalities respectively. Positive samples are further run on HPLC to determine the specific amino acids abnormality. An examples of a case of maple syrup urine disease is discussed, based on the thin layer chromatography findings and HPLC findings.
    Matched MeSH terms: Chromatography, High Pressure Liquid/methods
  2. Solid-liquid extraction of bioactive compounds with antioxidant potential from Alternanthera sesillis (red) and identification of the polyphenols using UHPLC-QqQ-MS/MS
    Mohd Hazli UHA, Abdul-Aziz A, Mat-Junit S, Chee CF, Kong KW
    Food Res Int, 2019 01;115:241-250.
    PMID: 30599938 DOI: 10.1016/j.foodres.2018.08.094
    Alternanthera sessilis (red) (ASR) is an edible herbal plant with many beneficial health effects. This study aimed to investigate the antioxidant components and antioxidant activities of the edible leaves and stems of ASR extracted using solvent of varying polarities namely water, ethanol, ethyl acetate and hexane. ASR leaf extracts showed higher in both antioxidant components and activities than the stem extracts. Among the antioxidant components, the ethanol leaf extract showed higher phenolic (77.29 ± 1.02 mg GAE/g extract) content while the ethyl acetate leaf extract was rich in flavonoids (157.44 ± 10.19 mg RE/g extract), carotenoids (782.97 ± 10.78 mg BE/g extract) and betalains (betanin: 67.08 ± 0.49 mg/g extract; amaranthin: 93.94 ± 0.68 mg/g extract and betaxanthin: 53.92 ± 0.88 mg/g extract). Nevertheless, the ethanol leaf extract showed the highest DPPH radical scavenging activity and ABTS radical cation scavenging activity. It also exhibited highest ferric reducing activity among all the extracts. Four polyphenolic compounds from ASR leaf, namely ferulic acid, rutin, quercetin and apigenin, were identified and quantified using ultra high performance liquid chromatography. The existence of these compounds was further verified using tandem mass spectrometry. These current results indicate that ASR leaf particularly the ethanol extract has the potential to be exploited as a source of natural antioxidants.
    Matched MeSH terms: Chromatography, High Pressure Liquid/methods*
  3. Organophosphorus Pesticide Multiresidues in Commercialized Asian Rice
    Azlan NSM, Wee SY, Ismail NAH, Nasir HM, Aris AZ
    Environ Toxicol Chem, 2020 10;39(10):1908-1917.
    PMID: 32621623 DOI: 10.1002/etc.4813
    The organophosphorus pesticides (OPPs) commonly used in agricultural practices can pose a risk of potential exposure to humans via food consumption. We describe an analytical method for solid-phase extraction coupled with high-performance liquid chromatography-diode array detector (SPE-HPLC-DAD) for the detection of OPPs (quinalphos, diazinon, and chlorpyrifos) in rice grains. The isolation of targeted residues was initiated with double extraction before SPE-HPLC-DAD, crucially reducing matrix interferences and detecting a wide range of multiple residues in rice grains. Coefficients of 0.9968 to 0.9991 showed a strong linearity, with limits of detection and quantification ranging from 0.36 to 0.68 µg/kg and from 1.20 to 2.28 µg/kg, respectively. High recoveries (80.4-110.3%) were observed at 3 spiking levels (50, 100, and 200 µg/kg), indicating good accuracy. The relative standard deviations of all residues (0.19-8.66%) validated the method precision. Sample analysis of 10 rice grain types (n = 30) available in the Asian market revealed that quinalphos, diazinon, and chlorpyrifos at concentrations of 1.08, 1.11, and 1.79 µg/kg, respectively, remained far below the maximum residue limits (0.01-0.5 mg/kg). However, regular monitoring is necessary to confirm that multiresidue occurrence remains below permissible limits while controlling pests. Environ Toxicol Chem 2020;39:1908-1917. © 2020 SETAC.
    Matched MeSH terms: Chromatography, High Pressure Liquid/methods
  4. Occurrence and potential risk of organophosphorus pesticides in urbanised Linggi River, Negeri Sembilan, Malaysia
    Zainuddin AH, Wee SY, Aris AZ
    Environ Geochem Health, 2020 Nov;42(11):3703-3715.
    PMID: 32488800 DOI: 10.1007/s10653-020-00604-4
    The application of organophosphorus pesticides (OPPs) increased gradually because of the rise in global food demand that triggered the agriculture sector to increase the production, leading to OPP residues in the surface water. This study elucidated the presence of OPPs and estimated its ecological risk in the riverine ecosystem of the urbanised Linggi River, Negeri Sembilan, Malaysia. The OPP concentration in surface water was determined using solid-phase extraction method and high-performance liquid chromatography coupled with diode array detection. Further, the ecological risk was estimated by using the risk quotient (RQ) method. The three OPPs, i.e. chlorpyrifos, diazinon, and quinalphos were detected with mean concentrations of 0.0275 µg/L, 0.0328 µg/L, and 0.0362 µg/L, respectively. The OPPs were at high risk (in general and worst cases) under acute exposure. The estimated risk of diazinon was observed as medium for general (RQm = 0.5857) and high for worst cases (RQex = 4.4678). Notably, the estimated risk for chlorpyrifos was high for both general and worst cases (RQm = 1.9643 and RQex = 11.5643) towards the aquatic ecosystem of the Linggi River. Chronic risk of quinalphos remains unknown because of the absence of toxicity endpoints. This study presented clear knowledge regarding OPP contamination and possible risk for aquatic ecosystems. Hence, OPPs should be listed as one of the main priority contaminants in pesticide mitigation management in the future.
    Matched MeSH terms: Chromatography, High Pressure Liquid/methods
  5. Porous graphitic carbon shows promise for the rapid screening partial DPD deficiency in lymphocyte dihydropyrimidine dehydrogenase in Chinese, Indian and Malay in Singapore by using semi-automated HPLC-radioassay
    Liem LK, Choong LH, Woo KT
    Clin Biochem, 2002 May;35(3):181-7.
    PMID: 12074825
    OBJECTIVE: Dihydropyrimidine dehydrogenase (DPD) catalyzes the degradation of thymine, uracil, and the chemotherapeutic drug 5-Fluorouracil. In general reverse-phase high pressure liquid chromatography is the standard method for separating 5-[2-(14)C]Fluorouracil and 5-[2-(14)C]Fluoro-5,6-dihydrouracil. However, the use of 100% aqueous solution (as HPLC mobile phase) may collapse the C-18 bonded phase and result in a retention time shift. The aim of this study is to develop a rapid, reproducible, sensitive method for screening partial DPD deficiency in healthy volunteers.

    DESIGN AND METHODS: The activity of DPD was measured using 5-[2- (14)C]Fluorouracil (5-[2-(14)C]FUra) followed by separation of substrate and product 5-[2-(14)C]FUraH(2) with a 15 x 4.6 mm I.D., 5 microm particle size (d(p)) porous graphitic carbon (PGC) column (Hypercarb(R)) and HPLC with online detection of the radioactivity. This was standardized using the protein concentration of the cytosol (NanoOrange(R) Protein Quantitation).

    RESULTS: Complete baseline separation of 5-[2-(14)C]Fluorouracil (5-[2-(14)C]FUra) and 5-[2-(14)C]Fluoro-5,6-dihydrouracil (5-[2-(14)C]FUraH(2)) was achieved using a porous graphitic carbon (PGC) column. The detection limit for 5-[2-(14)C]FUraH(2) was 0.4 pmol.

    CONCLUSIONS: By using linear gradient separation (0.1% Trifluoroacetic acid [TFA] in water to 100% Methanol) protocols in concert with PGC columns (Hypercarb(R)), we have demonstrated that a PGC column has a distinct advantage over C-18 reverse phase columns in terms of column stability (pH 1-14). This method provides an improvement on the specific assay for DPD enzyme activity. It is rapid, reproducible and sensitive and can be used for routine screening for healthy and cancer patients for partial and profound DPD deficiency before treatment with 5- FUra.

    Matched MeSH terms: Chromatography, High Pressure Liquid/methods*
  6. Salting-out assisted liquid-liquid extraction coupled with hydrophilic interaction chromatography for the determination of biguanides in biological and environmental samples
    Alshishani A, Salhimi SM, Saad B
    J Chromatogr B Analyt Technol Biomed Life Sci, 2018 Jan 15;1073:51-59.
    PMID: 29241085 DOI: 10.1016/j.jchromb.2017.12.013
    A new salting-out assisted liquid-liquid extraction (SALLE) sample preparation method for the determination of the polar anti-diabetic biguanide drugs (metformin, buformin and phenformin) in blood plasma, urine and lake water samples were developed. The SALLE was performed by mixing samples (plasma (0.2mL), urine or lake water (1.0mL)) with acetonitrile (0.4mL for plasma, 0.5mL for urine or lake water), sodium hydroxide powder was then added for the phase separation. The effects of type of salting-out reagent, type of extraction solvent, volumes of acetonitrile and sample, amount of sodium hydroxide, vortexing and centrifugation times on the extraction efficiency were investigated. The upper layer, containing the biguanides, was directly injected into a HPLC unit using ZIC-HILIC column (150mm×2.1mm×3.5μm) and was detected at 236nm. The method was validated and calibration curves were linear with r2>0.99 over the range of 20-2000μgL-1for plasma and 5-2000μgL-1for urine and lake water samples. The limits of detection were in the range (3.8-5.6)μgL-1, (0.8-1.5)μgL-1and (0.3-0.8)μgL-1for plasma, urine and lake water, respectively. The accuracies in the three matrices were within 87.3-103%, 87.4-109%, 82.2-109% of the nominal concentration for metformin, buformin and phenformin, respectively. The relative standard deviation for inter- and intra -day precision were in the range of 1.0-17% for all analytes in the three matrices.
    Matched MeSH terms: Chromatography, High Pressure Liquid/methods*
  7. Method development and validation for the simultaneous determination of imatinib mesylate and N-desmethyl imatinib using rapid resolution high performance liquid chromatography coupled with UV-detection
    Tan KL, Ankathil R, Gan SH
    J Chromatogr B Analyt Technol Biomed Life Sci, 2011 Nov 15;879(30):3583-91.
    PMID: 22000961 DOI: 10.1016/j.jchromb.2011.09.048
    We developed a simple and sensitive method for the simultaneous detection of imatinib mesylate (IM) and its active metabolite, N-desmethyl imatinib (M1), in human serum samples. Separation was successfully achieved using an Agilent(®) ZORBAX Eclipse plus C(18) reversed phase column (50 mm × 2.1 mm, i.d.; 1.8 μm) under isocratic mobile phase conditions consisting of acetonitrile: 0.02 M potassium dihydrogen phosphate with 0.2% triethylamine at pH 3 (25:75, v/v) and ultra-violet detection was achieved at 235 nm. Extraction of the target compounds was completed using 100% cold acetonitrile. Good linearities (r(2)>0.99) for both IM and M1 were achieved for the concentration ranges of 50-1800 ng/mL and 50-360 ng/mL, respectively. The detection limits were 20 ng/mL and 10 ng/mL for M1 and IM, respectively. The intra- and inter-day precisions were less than 1% with percent recoveries of more than 90%. The method was successfully applied to calculate the pharmacokinetic parameters of chronic myeloid leukemia patients receiving imatinib. The method is suitable to be routinely applied for determination of IM and M1 in serum.
    Matched MeSH terms: Chromatography, High Pressure Liquid/methods*
  8. High-performance thin-layer chromatography HPTLC-direct bioautography as a method of choice for alpha-amylase and antioxidant activity evaluation in marine algae
    Agatonovic-Kustrin S, Morton DW
    J Chromatogr A, 2017 Dec 29;1530:197-203.
    PMID: 29157606 DOI: 10.1016/j.chroma.2017.11.024
    High-Performance Thin-layer chromatography (HPTLC) combined with DPPH free radical method and α-amylase bioassay was used to compare antioxidant and antidiabetic activities in ethanol and ethyl acetate extracts from 10 marine macroalgae species (3 Chlorophyta, 4 Phaeophyta and 3 Rhodophyta) from Blue Lagoon beach (Malaysia). Samples were also evaluated for their phenolic and stigmasterol content. On average, higher antioxidant activity was observed in the ethyl acetate extracts (55.1mg/100g gallic acid equivalents (GAE) compared to 35.0mg/100g GAE) while, as expected, phenolic content was higher in ethanol extracts (330.5mg/100g GAE compared to 289.5mg/100g GAE). Amounts of fucoxanthin, stigmasterol and α-amylase inhibitory activities were higher in ethyl acetate extracts. Higher enzyme inhibition is therefore related to higher concentrations of triterpenes and phytosterols (Note: these compounds are more soluble in ethyl acetate). Ethyl acetate extracts from Caulerpa racemosa and Padina minor, had the highest α-amylase inhibitory activity, and also showed moderately high antioxidant activities, stigmasterol content and polyphenolic content. Caulerpa racemose, being green algae, does not contain fucoxanthin, while Padina minor, being brown algae, contains high amounts of fucoxanthin. Therefore, it is very unlikely that fucoxanthin contributes to α-amylase inhibitory activity as previously reported.
    Matched MeSH terms: Chromatography, High Pressure Liquid/methods*
  9. Fulltext Mechanistic Studies of the Antiallergic Activity of Phyllanthus amarus Schum. & Thonn. and Its Compounds
    Abd Rani NZ, Lam KW, Jalil J, Mohamad HF, Mat Ali MS, Husain K
    Molecules, 2021 Jan 28;26(3).
    PMID: 33525733 DOI: 10.3390/molecules26030695
    Phyllanthus amarus Schum. & Thonn. (Phyllanthaceae) is a medicinal plant that is commonly used to treat diseases such as asthma, diabetes, and anemia. This study aimed to examine the antiallergic activity of P. amarus extract and its compounds. The antiallergic activity was determined by measuring the concentration of allergy markers release from rat basophilic leukemia (RBL-2H3) cells with ketotifen fumarate as the positive control. As a result, P. amarus did not stabilize mast cell degranulation but exhibited antihistamine activity. The antihistamine activity was evaluated by conducting a competition radioligand binding assay on the histamine 1 receptor (H1R). Four compounds were identified from the high performance liquid chromatography (HPLC) analysis which were phyllanthin (1), hypophyllanthin (2), niranthin (3), and corilagin (4). To gain insights into the binding interactions of the most active compound hypophyllanthin (2), molecular docking was conducted and found that hypophyllanthin (2) exhibited favorable binding in the H1R binding site. In conclusion, P. amarus and hypophyllanthin (2) could potentially exhibit antiallergic activity by preventing the activation of the H1 receptor.
    Matched MeSH terms: Chromatography, High Pressure Liquid/methods
  10. Development and validation of RP-HPLC-UV method for simultaneous determination of buparvaquone, atenolol, propranolol, quinidine and verapamil: a tool for the standardization of rat in situ intestinal permeability studies
    Venkatesh G, Ramanathan S, Mansor SM, Nair NK, Sattar MA, Croft SL, et al.
    J Pharm Biomed Anal, 2007 Mar 12;43(4):1546-51.
    PMID: 17157469
    A simple, sensitive and specific reversed phase high performance liquid chromatographic (RP-HPLC) method with UV detection at 251 nm was developed for simultaneous quantitation of buparvaquone (BPQ), atenolol, propranolol, quinidine and verapamil. The method was applicable in rat in situ intestinal permeability study to assess intestinal permeability of BPQ, a promising lead compound for Leishmania donovani infections. The method was validated on a C-4 column with mobile phase comprising ammonium acetate buffer (0.02 M, pH 3.5) and acetonitrile in the ratio of 30:70 (v/v) at a flow rate of 1.0 ml/min. The retention times for atenolol, quinidine, propranolol, verapamil and BPQ were 4.30, 5.96, 6.55, 7.98 and 8.54 min, respectively. The calibration curves were linear (correlation coefficient > or =0.996) in the selected range of each analyte. The method is specific and sensitive with limit of quantitation of 15 microg/ml for atenolol, 0.8 microg/ml for quinidine, 5 microg/ml for propranolol, 10 microg/ml for verapamil and 200 ng/ml for BPQ. The validated method was found to be accurate and precise in the working calibration range. Stability studies were carried out at different storage conditions and all the analytes were found to be stable. This method is simple, reliable and can be routinely used for accurate permeability characterization.
    Matched MeSH terms: Chromatography, High Pressure Liquid/methods*
  11. HPTLC based approach for bioassay-guided evaluation of antidiabetic and neuroprotective effects of eight essential oils of the Lamiaceae family plants
    Romero Rocamora C, Ramasamy K, Meng Lim S, Majeed ABA, Agatonovic-Kustrin S
    J Pharm Biomed Anal, 2020 Jan 30;178:112909.
    PMID: 31618702 DOI: 10.1016/j.jpba.2019.112909
    A high-performance thin-layer chromatography (HPTLC) method combined with effect-directed-analysis (EDA) was developed to screen the antioxidant, neuroprotective and antidiabetic effects in essential oils derived from lavender flower, lemon myrtle, oregano, peppermint, sage, and rosemary leaves (Lamiaceae family). HPTLC hyphenated with microchemical (DPPH•, p-anisaldehyde, and ferric chloride) derivatizations, was used to evaluate antioxidant activity, presence of phytosterols and terpenoids, and polyphenolic content, while the combination with biochemical (α-amylase and acetylcholine esterase (AChE) enzymatic) derivatizations was used to asses α-amylase and AChE inhibitory activities. The superior antioxidant activity of oregano leaf extract is attributed to the presence of high levels of aromatic compounds, like polyphenolic acids. The strongest α-amylase inhibition was observed in lemon myrtle and rosemary plus extracts due to the presence of monoterpenes. Rosemary and sage extracts exhibit the highest AChE inhibition activity, with 1 μL essential oils being more potent than the recommended daily dose of donepezil. This superior neuroprotection was attributed to the presences of di- and triterpenes that displayed strong AChE inhibition and antioxidant potential in DPPH• free radical assay. Antioxidant activity was related to phenolic content (R = 0.49), while α-amylase inhibitory activity was positively related to antioxidant activity (R = 0.20) and terpenoid/sterol content (R = 0.31). AChE inhibitory activity was correlated (R = 0.80) to the combined effect of phenolics and terpenoids. Thus, the superior AChE inhibitory and neuroprotection potential of rosemary and sage essential oils could be attributed to joint effects of main phenolic and terpene constituents. The hyphenated HPTLC method provided rapid bioanalytical profiling of highly complex essential oil samples.
    Matched MeSH terms: Chromatography, High Pressure Liquid/methods*
Related Terms
Filters
Contact Us

Please provide feedback to Administrator (afdal@afpm.org.my)

External Links