Displaying publications 81 - 100 of 151 in total

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  1. Thevarajah M, Nadzimah MN, Chew YY
    Clin Biochem, 2009 Mar;42(4-5):430-4.
    PMID: 19026622 DOI: 10.1016/j.clinbiochem.2008.10.015
    Glycated hemoglobin, measured as HbA1c is used as an index of mean glycemia in diabetic patients over the preceding 2-3 months. Various assay methods are used to measure HbA1c and many factors may interfere with its measurement according to assay method used, causing falsely high or low results.
    Matched MeSH terms: Chromatography, High Pressure Liquid/methods*
  2. Saleem H, Sarfraz M, Khan KM, Anwar MA, Zengin G, Ahmad I, et al.
    Drug Dev Ind Pharm, 2020 May;46(5):861-868.
    PMID: 32352878 DOI: 10.1080/03639045.2020.1762199
    The biological, chemical, and in silico properties of methanol and dichloromethane (DCM) extracts of Alhagi maurorum roots with respect to the antioxidant, enzyme inhibition, and phytochemical composition were evaluated. Total bioactive contents were determined spectrophotometrically, and the individual secondary metabolites composition was assessed via ultra-high-performance liquid chromatography mass spectrometry (UHPLC-MS) analysis. Antioxidant capacities were evaluated using a panoply of assays (2,2-diphenyl-1-picrylhydrazyl (DPPH), 2,2'-azino-bis (3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) free radical scavenging, ferric reducing antioxidant power (FRAP), cupric reducing antioxidant power (CUPRAC), phosphomolybdenum total antioxidant capacity (TAC), and metal chelating activity (MCA)). The enzyme inhibition potential was studied against acetylcholinesterase (AChE), butyrylcholinesterase (BChE), α-amylase, α-glucosidase, tyrosinase, urease and lipoxygenase (LOX) enzymes. The methanol extract was found to contain higher total phenolic (105.91 mg GAE/g extract) and flavonoid (2.27 mg RE/g extract) contents which can be correlated to its more substantial antioxidant potential as well as AChE, BChE, tyrosinase and α-glucosidase inhibition. However, the DCM extract was the most effective against α-amylase (1.86 mmol ACAE/g extract) enzyme inhibition. The UHPLC-MS analysis of methanol extract identified the tentative presence of a total of 18 secondary metabolites, including flavonoids, saponins, phenolic and terpenoid derivatives. Three compounds named emmotin A, luteolin 5,3'-dimethyl ether, and preferrugone were further investigated for their in silico molecular docking studies against the tested enzymes. The selected compounds were found to have higher binding interaction with AChE followed by BChE, α-glucosidase, α-amylase, and tyrosinase. The results of the present study have demonstrated A. mauroram to be considered as a lead source of natural antioxidant and enzyme inhibitor compounds.
    Matched MeSH terms: Chromatography, High Pressure Liquid/methods
  3. Baig MA, Swamy KB, Baksh AD, Bahashwan A, Moshrif Y, Al Sawat A, et al.
    Indian J Pathol Microbiol, 2021 8 4;64(3):518-523.
    PMID: 34341263 DOI: 10.4103/IJPM.IJPM_709_20
    Background: : HPLC is one of the most important tools for accurate diagnosis of hemoglobinopathies and thalassemias. The advantage of the HPLC system is the excellent resolution, reproducibility &quantification of several normal and abnormal hemoglobin.

    Results: BIO RAD Variant II analyzer was used. Sickle cell syndromes including double heterozygous states accounted for 56.13% of total cases. HbSS, HbS/β0-th, HbS/β+-th β-thal trait comprises 29%, 6.5%, 5.1%& 10% of total cases respectively with mean MCV (fl) = 84, 68,71,64 respectively. The Mean HbA2 for β-thal trait, HbE trait &HbE-β thal showed 5.1 ± 1.1, 19 ± 9 & 24 ± 8 respectively. HbF is increased in 8.6% case (excluding SC syndromes & β-thal disorders), of these 5.5% were infants & 12 cases of Aplastic Anemias. Peak P2 >7% (2.4% cases) was seen in uncontrolled diabetes mellitus which on quantification showed HbA1C = 8 ± 2.1 mmol/L.

    Discussion: : HPLC in correlation with CBC parameters & family studies can aid in the diagnosis of majority of Hemoglobinopathies and thalassemic syndrome. The CBC & HPLC parameters of the present study are in good correlation with the research conducted by Tejinder Sing, RiouJ & Alla Joutovsky. Present study showed HPLC comprehensively characterizing HbS, A, A2, F, S, C, D from each other & was also applicable for the quantification of HbA1c for the monitoring of Diabetes Mellitus.

    Conclusion: : The merits of HPLC are small quantity of sample required, economical, less TAT, accurate categorization of HbS, HbA2 & F. But one has to be aware of the limitations and problems associated with this method due to variant hemoglobin within the same retention windows. The present findings show HPLC as an excellent & powerful diagnostic tool for the direct identification of hemoglobin variants with a high degree of precision in the quantification of normal and abnormal hemoglobin fractions.

    Matched MeSH terms: Chromatography, High Pressure Liquid/methods*
  4. Chan KL, Yuen KH, Jinadasa S, Peh KK, Toh WT
    Planta Med, 1997 Feb;63(1):66-9.
    PMID: 9063097
    A high-performance liquid chromatography assay equipped with a glassy carbon electrode for electrochemical detection (HPLC-ECD) was developed at reductive mode for the analysis of artemisinin, the antimalarial drug from Artemisia annua (Asteraceae) in human plasma. This method was selective, sensitive, and produced satisfactory recovery, precision, and accuracy. Analysis of plasma samples from 8 male volunteers given 10 mg kg-1 of artemisinin orally as an aqueous suspension showed a mean peak plasma concentration (Cmax) of 580.89 ng ml-1 +/- 88.64 SD at 2.5 h +/- 0.5 SD after dosing, and the mean area under the plasma concentration-time curve (AUC0-infinity) was 2227.57 ng h ml-1 +/- 677.22 SD. In addition, the elimination rate constant (Ke), elimination half-life (t1/2), and apparent volume of distribution (Vd) were calculated to be 0.2971 h-1 +/- 0.0644 SD, 2.42 h +/- 0.46 SD, and 16.26 l kg-1 +/- 3.44 SD, respectively.
    Matched MeSH terms: Chromatography, High Pressure Liquid/methods*
  5. Shehzadi N, Hussain K, Khan MT, Salman M, Islam M
    Pak J Pharm Sci, 2017 Sep;30(5):1767-1777.
    PMID: 29084700
    The absence of chromophore and/or conjugated system, prerequisite for UV and florescent light detection, or absorbance at very low wavelength necessitates the development of simple and reliable methods for the determination of amikacin sulphate. Therefore, the present study describes for the first time dynamics of the drug derivatization using ninhydrin reagent and development and validation of a simple RP-HPLC method, using diode array detector (DAD). The variables such as heating time, heating type, drug-reagent ratio, reagent composition and storage temperature of the derivative were optimized. The analyte and aqueous ninhydrin solution upon heating for 2.00-5.00 min produced the colored drug-derivative which was stable for one month at refrigeration. The derivatized drug (20.00μL) was eluted through a column - Eclipse DB-C18 (5.00 µm, 4.60×150.00 mm), maintained at 25°C- using isocratic mobile phase comprising water and acetonitrile (70:30, v/v) at a flow rate of 1.00 mL/min, and detected at 400 nm. The method was found to be reliable (98.08-100.72% recovery), repeatable (98.02-100.72% intraday accuracy) and reproducible (98.47-101.27% inter day accuracy) with relative standard deviation less than 5%. The results of the present study indicate that the method is easy to perform, specific and sensitive, and suitable to be used for the determination of amikacin sulphate in bulk and pharmaceutical preparations using less expensive/laborious derivatization.
    Matched MeSH terms: Chromatography, High Pressure Liquid/methods*
  6. Fong CB, Thong MK, Sam CK, Mohamed Noor MN, Ariffin R
    Singapore Med J, 2009 May;50(5):529-33.
    PMID: 19495527
    Rett syndrome (RS) is a severe neurodevelopmental disorder characterised by normal neurological development followed by progressive developmental regression. The X-linked dominant inheritance of RS has been mapped to the gene that encodes the methyl-CpG-binding protein-2 (MECP2) at Xq28. In the present study, denaturing high-performance liquid chromatography (DHPLC) was used to detect mutations in the MECP2 gene in 20 Malaysian RS patients.
    Matched MeSH terms: Chromatography, High Pressure Liquid/methods
  7. Abubakar BM, Salleh FM, Shamsir Omar MS, Wagiran A
    Pharm Biol, 2018 Dec;56(1):368-377.
    PMID: 30058427 DOI: 10.1080/13880209.2018.1479869
    CONTEXT: Eurycoma longifolia Jack (Simaroubaceae) commonly known as Tongkat Ali is one of the most important plants in Malaysia. The plant extracts (particularly roots) are widely used for the treatment of cough and fever besides having antimalarial, antidiabetic, anticancer and aphrodisiac activities.

    OBJECTIVES: This study assesses the extent of adulteration of E. longifolia herbal medicinal products (HMPs) using DNA barcoding validated by HPLC analysis.

    MATERIALS AND METHODS: Chloroplastic rbcL and nuclear ITS2 barcode regions were used in the present study. The sequences generated from E. longifolia HMPs were compared to sequences in the GenBank using MEGABLAST to verify their taxonomic identity. These results were verified by neighbor-joining tree analysis in which branches of unknown specimen are compared to the reference sequences established from this study and other retrieved from the GenBank. The HMPs were also analysed using HPLC analysis for the presence of eurycomanone bioactive marker.

    RESULTS: Identification using DNA barcoding revealed that 37% of the tested HMPs were authentic while 27% were adulterated with the ITS2 barcode region proven to be the ideal marker. The validation of the authenticity using HPLC analysis showed a situation in which a species which was identified as authentic was found not to contain the expected chemical compound.

    DISCUSSION AND CONCLUSIONS: DNA barcoding should be used as the first screening step for testing of HMPs raw materials. However, integration of DNA barcoding with HPLC analysis will help to provide detailed knowledge about the safety and efficacy of the HMPs.

    Matched MeSH terms: Chromatography, High Pressure Liquid/methods
  8. Man F, Choo CY
    PMID: 28869873 DOI: 10.1016/j.jchromb.2017.08.037
    Bruceines D and E are quassinoids from seeds of Brucea javanica (L.) Merr. exhibiting hypoglycemia effect. The crude drug is used as a traditional medicine by diabetes patients. The aim of this study is to understand the bioavailability and pharmacokinetics of both the bruceines D & E. A rapid and sensitive HPLC-MS/MS method was developed and validated for the quantification of both quassinoids, bruceines D & E in rat plasma. Both the bruceines D & E were separated with the Zorbax SBC-18 column with gradient elution and mobile phase system of acetonitrile and deionized water with 0.1% formic acid at a flow rate of 0.5mL/min. Analytes were detected in multiple reaction monitoring (MRM) mode with electrospray positive ionization. The quassinoids, namely bruceines D & E were detected with transitions of m/z 411.2→393.2 and m/z 395.2→377.2, respectively. Another quassinoid, eurycomanone was used as the internal standard with transition of m/z 409.2→391.2. The method was validated and conformed to the regulatory requirements. The validated method was applied to pharmacokinetic and bioavailability studies in rats. The pharmacokinetic study indicated both bruceine D and E were rapidly absorbed into the circulation system and reached its peak concentration at 0.54±0.34h and 0.66±0.30h, respectively. Bruceine E was eliminated slower than Bruceine D with t1/2 value almost increased two-fold compared to Bruceine D. In conclusion, a rapid, selective and sensitive HPLC-MS/MS method was developed for the simultaneous determination of both the bruceines D and E in rat plasma. Both bruceines D and E displayed poor oral bioavailability.
    Matched MeSH terms: Chromatography, High Pressure Liquid/methods*
  9. Murugaiyah V, Chan KL
    PMID: 17261384
    A simple analytical method using HPLC with fluorescence detection was developed for the simultaneous determination of four lignans, phyllanthin (1), hypophyllanthin (2), phyltetralin (3) and niranthin (4) from Phyllanthus niruri L. in plasma. The method recorded limits of detection for 1, 2, 3 and 4 as 1.22, 6.02, 0.61 and 1.22 ng/ml, respectively, at a signal-to-noise ratio of 5:1 whereas their limits of quantification were 4.88, 24.41, 4.88 and 9.76 ng/ml, respectively, at a signal-to-noise ratio of 12:1. These values were comparable to those of other sensitive methods such as gas chromatography-mass spectrometry (GC-MS), high-performance liquid chromatography-MS (HPLC-MS) and HPLC-electrochemical detection (HPLC-ECD) for the analysis of plasma lignans. A further advantage over known methods was its simple protocol for sample preparation. The within-day and between-day accuracies for the analysis of the four lignans were between 87.69 and 110.07% with precision values below 10.51%. Their mean recoveries from extraction were between 91.39 and 114.67%. The method was successfully applied in the pharmacokinetic study of lignans in rats. Following intravenous administration, the lignans were eliminated slowly from the body with a mean clearance of 0.04, 0.01, 0.03 and 0.02 l/kg h and a mean half-life of 3.56, 3.87, 3.35 and 4.40 h for 1, 2, 3 and 4, respectively. Their peak plasma concentration upon oral administration was 0.18, 0.56, 0.12 and 0.62 microg/ml, respectively, after 1h. However, their absorption was incomplete with a calculated absolute oral bioavailability of 0.62, 1.52, 4.01 and 2.66% for 1, 2, 3 and 4, respectively.
    Matched MeSH terms: Chromatography, High Pressure Liquid/methods*
  10. Wong JW, Nisar UR, Yuen KH
    PMID: 14643517
    A sensitive and selective high-performance liquid chromatographic method was developed for the determination of itraconazole and its active metabolite, hydroxyitraconazole, in human plasma. Prior to analysis, both compounds together with the internal standard were extracted from alkalinized plasma samples using a 3:2 (v/v) mixture of 2,2,4-trimethylpentane and dichloromethane. The mobile phase comprised 0.02 M potassium dihydrogen phosphate-acetonitrile (1:1, v/v) adjusted to pH 3.0. Analysis was run at flow-rate of 0.9 ml/min with excitation and emission wavelengths set at 260 and 365 nm, respectively. Itraconazole was found to adsorb on glass or plastic tubes, but could be circumvented by prior treating the tubes using 10% dichlorodimethylsilane in toluene. Moreover, rinsing the injector port with acetonitrile helped to overcome any carry-over effect. This problem was not encountered with hydroxyitraconazole. The method was sensitive with limit of quantification of 3 ng/ml for itraconazole and 6 ng/ml for hydroxyitraconazole. The calibration curve was linear over a concentration range of 2.8-720 ng/ml for itraconazole and 5.6-720 ng/ml for the hydroxy metabolite. Mean recovery value of the extraction procedure for both compounds was about 85%, while the within-day and between-day coefficient of variation and percent error values of the assay method were all less than 15%. Hence, the method is suitable for use in pharmacokinetic and bioavailability studies of itraconazole.
    Matched MeSH terms: Chromatography, High Pressure Liquid/methods*
  11. Gam LH, Tham SY, Latiff A
    PMID: 12860026
    A confirmatory and quantitative HPLC-tandem mass spectrometry (MS-MS) method for human chorionic gonadotropin hormone (hCG) at concentrations as low as 5 IU/l following immunoaffinity extraction of the glycoprotein from urine was developed. The extraction method involved retention of urinary hCG in the immunoaffinity column via specific antigen-antibody interaction. A variety of eluents were then used to quantitatively elute hCG from the immunoaffinity column. Qualitative and quantitative analysis of hCG were undertaken using MS-MS by identifying the amino acid sequence of the marker peptide betaT5 obtained from hCG by tryptic digestion and the peak areas of three product ions b(6)(+), b(9)(+) and y(11)(+), respectively.
    Matched MeSH terms: Chromatography, High Pressure Liquid/methods*
  12. Hadi H, Makahleh A, Saad B
    PMID: 22503735 DOI: 10.1016/j.jchromb.2012.03.031
    A hollow fiber liquid phase microextraction (HF-LPME) in conjunction with reversed phase HPLC-UV method was developed for the extraction and determination of trace amounts of the antidiabetic drug, mitiglinide (MIT) in biological fluids. The drug was extracted from 10 mL aqueous sample (donor phase (DP)) into an organic phase impregnated in the pores of hollow fiber, followed by the back extraction into a second aqueous solution (acceptor phase (AP)) located in the lumen of the hollow fiber. Parameters influencing the extraction efficiency including the kind of organic solvent, composition of DP and AP, extraction time, stirring rate and salt addition were investigated and optimized. Under the optimized extraction conditions, high enrichment factors (210-fold), good linearity (5-1000 ng mL(-1)) and detection limit lower than 1.38 ng mL(-1) were achieved. Recoveries of spiked samples were in the range (88.3-96.3%) and (92.0-99.3%) for urine and plasma samples, respectively. The percent relative standard deviation (n=9) for the extraction and determination of three concentration levels (100, 400 and 800 ng mL(-1)) of MIT were less than 10.6% and 13.6% for urine and plasma samples, respectively. The developed method is simple, sensitive and has been successfully applied to the analysis of MIT in biological fluids.
    Matched MeSH terms: Chromatography, High Pressure Liquid/methods*
  13. Gan SH, Ismail R, Wan Adnan WA, Wan Z
    PMID: 12016023
    An HPLC system using a simple liquid-liquid extraction and HPLC with UV detection has been validated to determine tramadol concentration in human plasma. The method developed was selective and linear for concentrations ranging from 10 to 2000 ng/ml with average recovery of 98.63%. The limit of quantitation (LOQ) was 10 ng/ml and the percentage recovery of the internal standard phenacetin was 76.51%. The intra-day accuracy ranged from 87.55 to 105.99% and the inter-day accuracy, 93.44 to 98.43% for tramadol. Good precision (5.32 and 6.67% for intra- and inter-day, respectively) was obtained at LOQ. The method has been applied to determine tramadol concentrations in human plasma samples for a pharmacokinetic study.
    Matched MeSH terms: Chromatography, High Pressure Liquid/methods*
  14. Abdullah N, Goh YX, Othman R, Ismail N, Jalal N, Wan Sallam WAF, et al.
    J Clin Lab Anal, 2023 Apr;37(8):e24898.
    PMID: 37243371 DOI: 10.1002/jcla.24898
    OBJECTIVE: Glycated haemoglobin (HbA1c) is a standard indication for screening type 2 diabetes that also has been widely used in large-scale epidemiological studies. However, its long-term quality (in terms of reproducibility) stored in liquid nitrogen is still unknown. This study is aimed to evaluate the stability and reproducibility of HbA1c measurements from frozen whole blood samples kept at -196°C for more than 7 years.

    METHODS: A total of 401 whole blood samples with a fresh HbA1c measurement were randomly selected from The Malaysian Cohort's (TMC) biobank. The HbA1c measurements of fresh and frozen (stored for 7-8 years) samples were assayed using different high-performance liquid chromatography (HPLC) systems. The HbA1c values of the fresh samples were then calculated and corrected according to the later system. The reproducibility of HbA1c measurements between calculated-fresh and frozen samples was assessed using a Passing-Bablok linear regression model. The Bland-Altman plot was then used to evaluate the concordance of HbA1c values.

    RESULTS: The different HPLC systems highly correlated (r = 0.99) and agreed (ICC = 0.96) with each other. Furthermore, the HbA1c measurements for frozen samples strongly correlate with the corrected HbA1c values of the fresh samples (r = 0.875) with a mean difference of -0.02 (SD: -0.38 to 0.38). Although the mean difference is small, discrepancies were observed within the diabetic and non-diabetic samples.

    CONCLUSION: These data demonstrate that the HbA1c measurements between fresh and frozen samples are highly correlated and reproducible.

    Matched MeSH terms: Chromatography, High Pressure Liquid/methods
  15. Ghasemzadeh A, Jaafar HZ, Rahmat A
    Molecules, 2010 Sep 03;15(9):6231-43.
    PMID: 20877219 DOI: 10.3390/molecules15096231
    Flavonoids make up one of the most pervasive groups of plant phenolics. Due to their importance in plants and human health, it would be useful to have a better understanding of flavonoid concentration and biological activities that could indicate their potentials as therapeutic agents, and also for predicting and controlling the quality of medicinal herbs. Ginger (Zingiber officinale Roscoe) is a famous and widely used herb, especially in Asia, that contains several interesting bioactive constituents and possesses health promoting properties. In this study, total flavonoids and some flavonoid components including quercetin, rutin, catechin, epicatechin, kaempferol and naringenin were extracted from the leaves and rhizomes of two varieties of Zingiber officinale (Halia Bentong and Halia Bara) at three different growth points (8, 12 and 16 weeks after planting), and analyzed by a high performance liquid chromatography (HPLC) method in order to determine the potential of the subterranean part of the young ginger. The results showed that Halia Bara had a higher content of flavonoids in the leaves and rhizomes as compared to Halia Bentong. In both varieties, the concentration of flavonoids in the leaves decreased (Halia Bentong, 42.3%; Halia Bara 36.7%), and in the rhizomes it increased (Halia Bentong 59.6%; Halia Bara 60.1%) as the growth period increased. Quercetin was abundant in both varieties. The antioxidant activity determined by the 1,1-diphenyl-2-picryl-hydrazyl (DPPH) assay showed high activities (65.7%) in the leaves of Halia Bara at 8 weeks after planting. Results suggested a good flavonoid content and antioxidant activity potential in ginger leaves at 8 weeks after planting. The leaves of these ginger varieties could be useful for both food flavourings and in traditional medicine.
    Matched MeSH terms: Chromatography, High Pressure Liquid/methods
  16. Shaik MM, Gan SH
    Indian J Pharmacol, 2013 Mar-Apr;45(2):159-67.
    PMID: 23716893 DOI: 10.4103/0253-7613.108303
    Hyperhomocysteinemia and vitamins B(6), B(9), and B(12) deficiencies usually result in various neurological, vascular, ocular, renal, and pulmonary abnormalities. However, to date, there are no simultaneous detection methods available for determining homocysteine, vitamins B(6), B(9), and B(12) levels in various biological fluids. In this study, we aim to develop a new validated simultaneous detection method for all four compounds to save both cost and time of analysis.
    Matched MeSH terms: Chromatography, High Pressure Liquid/methods*
  17. Cheong NDH, Mohamed E, Haron N, Camalxaman SN, Abdullah A, Mohamad Yusof MI, et al.
    Med J Malaysia, 2024 Mar;79(Suppl 1):34-39.
    PMID: 38555883
    INTRODUCTION: Parkia speciosa Hassk., commonly known as bitter bean or twisted cluster bean, is a tropical leguminous plant species native to Southeast Asia. The plant's edible pods have been traditionally used in various cuisines, particularly in Malaysian, Thai, and Indonesian cooking. Apart from being used as a food ingredient, the pods of P. speciosa also have a range of potential applications in other fields, including medicine, agriculture, and industry. The pods are said to have several phytochemicals that hold great therapeutic values such as reducing inflammation, improving digestion, and lowering blood sugar levels. However, there is limited information on the specific phytochemical contents of the pods in the literature. Thus, the aim of this study is to quantify the total phenolic and flavonoid compounds and to determine the concentrations of four selected phytochemical compounds in the P. speciosa pod extract (PSPE).

    MATERIALS AND METHODS: Quantification of the total phenolic (TPC) and flavonoid contents (TFC) in PSPE were done via colourimetric methods; and the determination of the concentrations of four specific phytochemicals (gallic acid, caffeic acid, rutin, and quercetin) were done via High- Performance Liquid Chromatography (HPLC).

    RESULTS: Colourimetric determination of PSPE showed TPC and TFC values of 84.53±9.40 mg GAE/g and 11.96±4.51 mg QE/g, respectively. Additional analysis of the phytochemicals using HPLC revealed that there were 6.45±3.36 g/kg, 5.91±1.07 g/kg, 0.39±0.84 g/kg, and 0.19±0.47 g/kg of caffeic acid, gallic acid, rutin, and quercetin, respectively.

    CONCLUSION: The findings show that PSPE contains substantial amounts of caffeic acid, gallic acid, rutin, and quercetin, which may indicate its potential as antibacterial, anti-inflammatory, anti-lipid, and antiviral medicines.

    Matched MeSH terms: Chromatography, High Pressure Liquid/methods
  18. Eukun Sage E, Jailani N, Md Taib AZ, Mohd Noor N, Mohd Said MI, Abu Bakar M, et al.
    PLoS One, 2018;13(10):e0205753.
    PMID: 30321238 DOI: 10.1371/journal.pone.0205753
    The pulp and pericarp of mangosteen (Garcinia mangostana) fruit are popular food, beverage and health products whereby 60% of the fruit consist of the pericarp. The major metabolite in the previously neglected or less economically significant part of the fruit, the pericarp, is the prenylated xanthone α-mangostin. This highly bioactive secondary metabolite is typically isolated using solvent extraction methods that involve large volumes of halogenated solvents either via direct or indirect extraction. In this study, we compared the quantities of α-mangostin extracted using three different extraction methods based on the environmentally friendly solvents methanol and ethyl acetate. The three solvent extractions methods used were direct extractions from methanol (DM) and ethyl acetate (DEA) as well as indirect extraction of ethyl acetate obtained via solvent partitioning from an initial methanol extract (IEA). Our results showed that direct extraction afforded similar and higher quantities of α-mangostin than indirect extraction (DM: 318 mg; DEA: 305 mg; IEA: 209 mg per 5 g total dried pericarp). Therefore, we suggest that the commonly used method of indirect solvent extraction using halogenated solvents for the isolation of α-mangostin is replaced by single solvent direct extraction using the environmentally friendly solvents methanol or ethyl acetate.
    Matched MeSH terms: Chromatography, High Pressure Liquid/methods
  19. Liew KB, Loh GO, Tan YT, Peh KK
    Biomed Chromatogr, 2015 Jun;29(6):953-60.
    PMID: 25400284 DOI: 10.1002/bmc.3378
    A simple, rapid, specific and reliable UFLC coupled with ESI-MSMS assay method to simultaneously quantify sildenafil and N-desmethyl sildenafil, with loperamide as internal standard, was developed. Chromatographic separation was performed on a Thermo Scientific Accucore C18 column with an isocratic mobile phase composed of 0.1% v/v formic acid in purified water-methanol (20:80, v/v), at a flow rate of 0.3 mL/min. Sildenafil, N-desmethyl sildenafil and loperamide were detected with proton adducts at m/z 475.4 > 58.2, 461.3 > 85.2 and 477.0 > 266.1 in multiple reaction monitoring positive mode, respectively. Both analytes and internal standard were extracted by diethyl ether. The method was validated over a linear concentration range of 10-800 ng/mL for sildenafil and 10-600 ng/mL for N-desmethyl sildenafil with correlation coefficient (r(2) ) ≥0.9976 for sildenafil and (r(2) ) ≥0.9992 for N-desmethyl sildenafil. The method was precise, accurate and stable. The proposed method was applied to study the bioequivalence between a 100 mg dose of two pharmaceutical products: Viagra (original) and Edyfil (generic) products. AUC0-t , Cmax and Tmax were 2285.79 ng h/mL, 726.10 ng/mL and 0.94 h for Viagra and 2363.25 ng h/mL, 713.91 ng/mL and 0.83 hour for Edyfil. The 90% confidence interval of these parameters of this study fall within the regulatory range of 80-125%, hence they are considered as bioequivalent.
    Matched MeSH terms: Chromatography, High Pressure Liquid/methods*
  20. Muniroh MS, Sariah M, Zainal Abidin MA, Lima N, Paterson RR
    J Microbiol Methods, 2014 May;100:143-7.
    PMID: 24681306 DOI: 10.1016/j.mimet.2014.03.005
    Detection of basal stem rot (BSR) by Ganoderma of oil palms was based on foliar symptoms and production of basidiomata. Enzyme-Linked Immunosorbent Assays-Polyclonal Antibody (ELISA-PAB) and PCR have been proposed as early detection methods for the disease. These techniques are complex, time consuming and have accuracy limitations. An ergosterol method was developed which correlated well with the degree of infection in oil palms, including samples growing in plantations. However, the method was capable of being optimised. This current study was designed to develop a simpler, more rapid and efficient ergosterol method with utility in the field that involved the use of microwave extraction. The optimised procedure involved extracting a small amount of Ganoderma, or Ganoderma-infected oil palm suspended in low volumes of solvent followed by irradiation in a conventional microwave oven at 70°C and medium high power for 30s, resulting in simultaneous extraction and saponification. Ergosterol was detected by thin layer chromatography (TLC) and quantified using high performance liquid chromatography with diode array detection. The TLC method was novel and provided a simple, inexpensive method with utility in the field. The new method was particularly effective at extracting high yields of ergosterol from infected oil palm and enables rapid analysis of field samples on site, allowing infected oil palms to be treated or culled very rapidly. Some limitations of the method are discussed herein. The procedures lend themselves to controlling the disease more effectively and allowing more effective use of land currently employed to grow oil palms, thereby reducing pressure to develop new plantations.
    Matched MeSH terms: Chromatography, High Pressure Liquid/methods*
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