Displaying publications 541 - 560 of 680 in total

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  1. Saleem H, Htar TT, Naidu R, Nawawi NS, Ahmad I, Ashraf M, et al.
    Food Chem Toxicol, 2019 Jan;123:363-373.
    PMID: 30419323 DOI: 10.1016/j.fct.2018.11.016
    We investigated into the effects of methanol and dichloromethane extracts from aerial and roots of Filago germanica (L.) Huds (Astearaceae) on key enzymes (cholinesterases, α-glucosidase and urease), antioxidant capabilities, cytotoxic potential and secondary metabolomics profile. Total phenolic and flavonoids were determined by spectrophotometric technique and secondary metabolites composition by UHPLC-MS. Antioxidant activities were assessed employing free radical scavenging, ferric reducing power and phosphomolybdenum assays. The cell-toxicity was evaluated by MTT assay against breast (MCF-7, MDA-MB-231), cervix (CaSki) and prostate (DU-145) cancers. Overall, methanol extracts were found to have higher total bioactive contents and antioxidant potential. UHPLC-MS analysis revealed significant variation in the secondary metabolites in the methanol extracts. The most common derivatives belong to seven groups i.e. alkaloids, benzoic acids, flavones, flavonols, flavan-3-ols, terpenoids and saponins. The major polyphenolic compounds were found to be kampferol, robinin, luteolin, ferulic acid, benzoic acid and salicylic acid. All the extracts showed moderate cholinesterases inhibition, whereas methanol extracts exhibited highest urease inhibition and all extracts presented a relatively high inhibition against α-glucosidase. Similarly, all extracts showed strong to moderate cytotoxicity with IC50 values ranging from 53.02 to 382.7 μg/mL. Overall, results have suggested F. germanica to be a lead source for novel natural products.
    Matched MeSH terms: Chromatography, High Pressure Liquid
  2. Rajedadram A, Pin KY, Ling SK, Yan SW, Looi ML
    J Zhejiang Univ Sci B, 2021 Feb 15;22(2):112-122.
    PMID: 33615752 DOI: 10.1631/jzus.B2000446
    This study aims to elucidate the antiproliferative mechanism of hydroxychavicol (HC). Its effects on cell cycle, apoptosis, and the expression of c-Jun N-terminal kinase (JNK) and P38 mitogen-activated protein kinase (MAPK) in HT-29 colon cancer cells were investigated. HC was isolated from Piper betle leaf (PBL) and verified by high-performance liquid chromatography (HPLC), nuclear magnetic resonance (NMR), and gas chromatography-mass spectrometry (GC-MS). The cytotoxic effects of the standard drug 5-fluorouracil (5-FU), PBL water extract, and HC on HT-29 cells were measured after 24, 48, and 72 h of treatment. Cell cycle and apoptosis modulation by 5-FU and HC treatments were investigated up to 30 h. Changes in phosphorylated JNK (pJNK) and P38 (pP38) MAPK expression were observed up to 18 h. The half maximal inhibitory concentration (IC50) values of HC (30 μg/mL) and PBL water extract (380 μg/mL) were achieved at 24 h, whereas the IC50 of 5-FU (50 μmol/L) was obtained at 72 h. Cell cycle arrest at the G0/G1 phase in HC-treated cells was observed from 12 h onwards. Higher apoptotic cell death in HC-treated cells compared to 5-FU-treated cells (P<0.05) was observed. High expression of pJNK and pP38 MAPK was observed at 12 h in HC-treated cells, but not in 5-FU-treated HT-29 cells (P<0.05). It is concluded that HC induces cell cycle arrest and apoptosis of HT-29 cells, with these actions possibly mediated by JNK and P38 MAPK.
    Matched MeSH terms: Chromatography, High Pressure Liquid
  3. Jusril NA, Muhamad Juhari ANN, Abu Bakar SI, Md Saad WM, Adenan MI
    Molecules, 2020 Jul 24;25(15).
    PMID: 32721993 DOI: 10.3390/molecules25153353
    Alzheimer's disease (AD) is a neurodegenerative disease and the most cause of dementia in elderly adults. Acetylcholinesterase (AChE) is an important beneficial target for AD to control cholinergic signaling deficit. Centella asiatica (CA) has proven to be rich with active ingredients for memory enhancement. In the present study, the chemical profiling of three accession extracts of CA namely SECA-K017, SECA-K018, and, SECA-K019 were performed using high-performance liquid chromatography (HPLC). Four biomarker triterpene compounds were detected in all CA accessions. Quantitative analysis reveals that madecassoside was the highest triterpene in all the CA accessions. The biomarker compounds and the ethanolic extracts of three accessions were investigated for their acetylcholinesterase (AChE) inhibitory activity using Ellman's spectrophotometer method. The inhibitory activity of the triterpenes and accession extracts was compared with the standard AChE inhibitor eserine. The results from the in vitro study showed that the triterpene compounds exhibited an AChE inhibitory activity with the half-maximal inhibitory concentration (IC50) values between 15.05 ± 0.05 and 59.13 ± 0.18 µg/mL. Asiatic acid was found to possess strong AChE inhibitory activity followed by madecassic acid. Among the CA accession extracts, SECA-K017 and SECA-K018 demonstrated a moderate AChE inhibitory activity with an IC50 value of 481.5 ± 0.13 and 763.5 ± 0.16 µg/mL, respectively from the in silico docking studies, it is observed that asiatic acid and madecassic acid showed very good interactions with the active sites and fulfilled docking parameters against AChE. The present study suggested that asiatic acid and madecassic acid in the CA accessions could be responsible for the AChE inhibitory action and could be used as markers to guide further studies on CA as potential natural products for the treatment of AD.
    Matched MeSH terms: Chromatography, High Pressure Liquid
  4. Akowuah GA, Zhari I, Mariam A
    Food Chem Toxicol, 2008 Dec;46(12):3616-20.
    PMID: 18824206 DOI: 10.1016/j.fct.2008.09.008
    A simple high-performance liquid chromatography (HPLC) method was developed to determine the content of andrographolide (AP) and 14-deoxy-11,12-dideoxyandrographolide (DIAP) in a pooled urine of rat obtained within 24h after an oral dose of Andrographis paniculata leaf extract at 1g/kg body weight. Cumulative urinary excretion of AP and DIAP in 24h after oral administration of the extract was 0.88% and 1.61% of oral dose administered, respectively. The extract showed significant reduction (p<0.05) of MDA levels and elevation of total antioxidant status in rat urine samples collected in 24 after oral administration.
    Matched MeSH terms: Chromatography, High Pressure Liquid
  5. Nasaruddin N, Jinap S, Samsudin NI, Kamarulzaman NH, Sanny M
    J Sci Food Agric, 2021 Mar 30;101(5):1812-1821.
    PMID: 32893877 DOI: 10.1002/jsfa.10795
    BACKGROUND: Corn, a main feed ingredient in the livestock industry, is one of the most susceptible crops to fungal infection and aflatoxin contamination. Livestock feeding on aflatoxin (AF)-contaminated feed have been shown to experience feed refusal, and decreased growth rate, milk production, and feed efficiency. In poultry, AF poisoning causes weight loss, poor feed efficiency, and reduced egg production and egg weight. The present work therefore aimed to determine the prevalence of mycotoxigenic fungi and the occurrence of AF contamination along the integrated corn-based poultry feed supply chain in Malaysia. A total of 51 samples were collected from different points along the feed supply chain from integrated poultry feed companies. The samples were subjected to mycological analyses (fungal isolation, enumeration, identification), and AFs were quantified by high-performance liquid chromatography equipped with a fluorescence detector (HPLC-FLD).

    RESULTS: Samples collected from sampling point 1 (company A) and sampling point 9 (company B) yielded the highest total fungal load (>log 4 CFU g-1 ). The prevalent fungal genera isolated were Aspergillus, Fusarium, and Penicillium spp. Aflatoxin B1 was detected in 8.3% of corn samples, and 7.4% of corn-based poultry feed samples along the feed supply chain, whereas AFs B2 , G1 , and G2 were not detected.

    CONCLUSION: The incidence of mycotoxigenic fungi along the integrated poultry feed supply chain warrant continuous monitoring of mycotoxin contamination to reduce the exposure risk of mycotoxin intake in poultry. © 2020 Society of Chemical Industry.

    Matched MeSH terms: Chromatography, High Pressure Liquid
  6. Wei J, Ren W, Wang L, Liu M, Tian X, Ding G, et al.
    J Sci Food Agric, 2020 Dec;100(15):5627-5636.
    PMID: 32712996 DOI: 10.1002/jsfa.10690
    BACKGROUND: Serofluid dish, a traditional Chinese fermented food, possesses unique flavors and health beneficial effects. These properties are likely due to the sophisticated metabolic networks during fermentation, which are mainly driven by microbiota. However, the exact roles of metabolic pathways and the microbial community during this process remain equivocal.

    RESULTS: Here, we investigated the microbial dynamics by next-generation sequencing, and outlined a differential non-targeted metabolite profiling in the process of serofluid dish fermentation using the method of hydrophilic interaction liquid chromatography column with ultra-high-performance liquid chromatography-quadruple time-of-flight mass spectrometry. Lactobacillus was the leading genus of bacteria, while Pichia and Issatchenkia were the dominant fungi. They all accumulated during fermentation. In total, 218 differential metabolites were identified, of which organic acids, amino acids, sugar and sugar alcohols, fatty acids, and esters comprised the majority. The constructed metabolic network showed that tricarboxylic acid cycle, urea cycle, sugar metabolism, amino acids metabolism, choline metabolism, and flavonoid metabolism were regulated by the fermentation. Furthermore, correlation analysis revealed that the leading fungi, Pichia and Issatchenkia, were linked to organic acids, amino acid and sugar metabolism, flavonoids, and several other flavor and functional components. Antibacterial tests indicated the antibacterial effect of serofluid soup against Salmonella and Staphylococcus.

    CONCLUSION: This work provides new insights into the complex microbial and metabolic networks during serofluid dish fermentation, and a theoretical basis for the optimization of its industrial production. © 2020 Society of Chemical Industry.

    Matched MeSH terms: Chromatography, High Pressure Liquid
  7. Sthaneshwar P, Shanmugam H, Arumugam S
    Pathology, 2014 Apr;46(3):263-5.
    PMID: 24614705 DOI: 10.1097/PAT.0000000000000090
    Matched MeSH terms: Chromatography, High Pressure Liquid
  8. George E, Teh LK, Tan J, Lai MI, Wong L
    Pathology, 2013 01;45(1):62-5.
    PMID: 23222244 DOI: 10.1097/PAT.0b013e32835af7c1
    AIMS: Classical carriers of β-thalassaemia are identified by a raised HbA2 level. Earlier studies indicated that the Filipino β-deletion has high raised HbA2 levels. The introduction of automated high performance liquid chromatography (HPLC) for thalassaemia screening is an important advance in technology for haematology laboratories. The BioRad Variant II Hb analyser is a common instrument used to quantify HbA2 levels in thalassaemia screening. This study aimed to determine HbA2 levels in carriers of Filipino β-mutation using the BioRad Variant II Hb analyser.

    METHODS: The Filipino β-deletion was identified using gap-polymerase chain reaction (PCR) in the parents of transfusion dependent β-thalassaemia patients who were homozygous for the Filipino β-deletion in the indigenous population of Sabah, Malaysia. Hb subtypes were quantified on the BioRad Variant II Hb analyser. Concurrent α-thalassaemia was identified by multiplex gap-PCR for deletions and amplification refractory mutation system (ARMS)-PCR for non-deletional mutations.

    RESULTS: The mean HbA2 level for Filipino β-thalassaemia trait was 5.9 ± 0.47 and with coinheritance of α-thalassaemia was 6.3 ± 0.44 (-α heterozygous) and 6.7 ± 0.36 (-α homozygous). The HbA2 levels were all >4% in keeping with the findings of classical β-thalassaemia trait and significantly higher than levels seen in non-deletional forms of β-thalassaemia.

    CONCLUSION: The HbA2 level measured on the BioRad Variant II Hb analyser was lower than the level in the first description of the Filipino β-thalassaemia. β-thalassaemia trait with coinheritance of α-thalassaemia (-α) is associated with significantly higher HbA2 level.

    Matched MeSH terms: Chromatography, High Pressure Liquid
  9. Ashhar Z, Yusof NA, Ahmad Saad FF, Mohd Nor SM, Mohammad F, Bahrin Wan Kamal WH, et al.
    Molecules, 2020 Jun 09;25(11).
    PMID: 32526838 DOI: 10.3390/molecules25112668
    Early diagnosis of bone metastases is crucial to prevent skeletal-related events, and for that, the non-invasive techniques to diagnose bone metastases that make use of image-guided radiopharmaceuticals are being employed as an alternative to traditional biopsies. Hence, in the present work, we tested the efficacy of a gallium-68 (68Ga)-based compound as a radiopharmaceutical agent towards the bone imaging in positron emitting tomography (PET). For that, we prepared, thoroughly characterized, and radiolabeled [68Ga]Ga-NODAGA-pamidronic acid radiopharmaceutical, a 68Ga precursor for PET bone cancer imaging applications. The preparation of NODAGA-pamidronic acid was performed via the N-Hydroxysuccinimide (NHS) ester strategy and was characterized using liquid chromatography-mass spectrometry (LC-MS) and tandem mass spectrometry (MSn). The unreacted NODAGA chelator was separated using the ion-suppression reverse phase-high performance liquid chromatography (RP-HPLC) method, and the freeze-dried NODAGA-pamidronic acid was radiolabeled with 68Ga. The radiolabeling condition was found to be most optimum at a pH ranging from 4 to 4.5 and a temperature of above 60 °C. From previous work, we found that the pamidronic acid itself has a good bone binding affinity. Moreover, from the analysis of the results, the ionic structure of radiolabeled [68Ga]Ga-NODAGA-pamidronic acid has the ability to improve the blood clearance and may exert good renal excretion, enhance the bone-to-background ratio, and consequently the final image quality. This was reflected by both the in vitro bone binding assay and in vivo animal biodistribution presented in this research.
    Matched MeSH terms: Chromatography, High Pressure Liquid
  10. Ghazali N, Rahman NA, Kannan TP, Jaafar S
    Cleft Palate Craniofac J, 2015 07;52(4):e88-94.
    PMID: 26151095 DOI: 10.1597/14-024
    OBJECTIVE: To determine the prevalence of mutations in transforming growth factor beta 3 (TGFβ3) and Jagged2 genes and their association with nonsyndromic cleft lip with or without cleft palate (CL±P) patients.

    DESIGN: Cross-sectional study on nonsyndromic CL±P and noncleft patients.

    SETTING: Reconstructive clinic and outpatient dental clinic, Hospital Universiti Sains Malaysia.

    PATIENTS: Blood samples of 96 nonsyndromic CL±P and 96 noncleft subjects.

    MAIN OUTCOME MEASURE: Prevalence and association of mutations in TGFβ3 and Jagged2 genes with nonsyndromic CL±P.

    RESULTS: Most of the nonsyndromic CL±P patients (53.1%) had left unilateral CLP. There were slightly more females (56.6%) compared with males. The prevalence of the mutations in the TGFβ3 gene was 17.7% (95% confidence interval [CI]: 9.5, 24.5) and in the Jagged2 gene was 12.5% (95% CI: 5.5, 18.5), which was higher compared with the noncleft group. For the TGFβ3 gene, there was no mutation in the coding region in either of the groups. All variants were single nucleotide polymorphisms located within the intronic flanking region. Two variants were identified (g.15812T>G and g.15966A>G) in both nonsyndromic CL±P and noncleft patients. However, the association was not significant (P > .05). Three variants (g.19779C>T, g.19547G>A, and g.19712C>T) were identified in the Jagged2 gene among nonsyndromic CL±P and noncleft patients. Only g.19712C>T showed a significant association with nonsyndromic CL±P patients (P = .039).

    CONCLUSION: g.19712C>T might play a crucial role in the development of cleft lip and palate. To the best of our knowledge, this is the first report of the mutation found within intron 13 of the Jagged2 gene among nonsyndromic CL±P Malay patients.

    Study site:Reconstructive and outpatient dental clinic, Hospital Universiti Sains Malaysia (HUSM)
    Matched MeSH terms: Chromatography, High Pressure Liquid
  11. Mohammad Noor HS, Ismail NH, Kasim N, Mediani A, Mohd Zohdi R, Ali AM, et al.
    Appl Biochem Biotechnol, 2020 Sep;192(1):1-21.
    PMID: 32215848 DOI: 10.1007/s12010-020-03304-y
    Patients are turning into herbs for the management of diabetes, which cause increasing in the demand of plant-based alternative medicines. Ficus deltoidea or locally known as "Mas Cotek" in Malaysia is a famous herbal plant. However, many varieties of F. deltoidea existed with varied antidiabetic activities inspire us to evaluate in vivo antidiabetic activity of the most available varieties of F. deltoidea. Therefore, antihyperglycemic effect of different varieties of F. deltoidea at dose 250 mg/kg was evaluated on streptozotocin-nicotinamide-induced diabetic rats and further assessed their urinary metabolites using proton nuclear magnetic resonance (1H-NMR). The hyperglycemic blood level improved towards normoglycemic state after 30 days of treatment with standardized extracts of F. deltoidea var. trengganuensis, var. kunstleri, and var. intermedia. The extracts also significantly managed the biochemical parameters in diabetic rats. Metabolomics results showed these varieties were able to manage the altered metabolites of diabetic rats by shifting some of the metabolites back to their normal state. This knowledge might be very important in suggesting the use of these herbs in long-term treatment for diabetes. The most potential variety can be recommended, which may be useful for further pharmacological studies and herbal authentication processes.
    Matched MeSH terms: Chromatography, High Pressure Liquid
  12. Choo WS, Birch EJ, Stewart I
    Lipids, 2009 Sep;44(9):807-15.
    PMID: 19727883 DOI: 10.1007/s11745-009-3334-2
    Lipase-catalyzed transesterification of flaxseed oil with cinnamic acid (CA) or ferulic acid (FA) using an immobilized lipase from Candida antarctica (E.C. 3.1.1.3) was conducted to evaluate whether the lipophilized products provided enhanced antioxidant activity in the oil. Lipase-catalyzed transesterification of flaxseed oil with CA or FA produced a variety of lipophilized products (identified using ESI-MS-MS) such as monocinnamoyl/feruloyl-diacylglycerol, dicinnamoyl-monoacylglycerol and monocinnamoyl-monoacylglycerol. The free radical scavenging activity of the lipophilized products of lipase-catalyzed transesterification of flaxseed oil with CA or FA toward 2,2-diphenyl-1-picrylhydrazyl radical (DPPH.) were both examined in ethanol and ethyl acetate. The polarity of the solvents proved important in determining the radical scavenging activity of the substrates. Unesterified FA showed the highest free radical scavenging activity among all substrates tested while CA had negligible activity. The esterification of CA or FA with flaxseed oil resulted in significant increase and decrease in the radical scavenging activity compared with the native phenolic acid, respectively. Based on the ratio of a substrate to DPPH. concentration, lipophilized FA was a much more efficient free radical scavenger compared to lipophilized CA and was able to provide enhanced antioxidant activity in the flaxseed oil. Lipophilized cinnamic acid did not provide enhanced radical scavenging activity in the flaxseed oil as the presence of natural hydrophilic antioxidants in the oil had much greater radical scavenging activity.
    Matched MeSH terms: Chromatography, High Pressure Liquid
  13. Soopramanien M, Khan NA, Sagathevan K, Siddiqui R
    Int Microbiol, 2021 Jan;24(1):47-56.
    PMID: 32737845 DOI: 10.1007/s10123-020-00139-9
    Pollution, unhygienic conditions and organic waste are detrimental to human health. On the contrary, animals living in polluted environments, feeding on organic waste and exposed to noxious agents such as heavy metals must possess remarkable properties against contracting diseases. Species such as cockroaches and water monitor lizards thrive in unhygienic conditions and feed on decaying matter. Here, we investigated the antitumour properties of metabolites produced by gut bacteria isolated from Varanus salvator (Asian water monitor lizard). An adult water monitor lizard and a juvenile water monitor lizard were acquired, and dissected. Their aerobic gut bacteria were isolated and identificated through 16S rDNA sequencing. Next, bacterial conditioned media (CM) were prepared and utilised for subsequent assays. Growth inhibition, MTT 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide cell viability assay, cytotoxicity and cell survival assays were accomplished against a panel of cancer cells as well as a normal cell line. Furthermore, liquid chromatography-mass spectrometry (LC-MS) was employed to identify potential antitumour molecules. A plethora of bacteria were isolated from the gut of juvenile and adult V. salvator respectively. Moreover, CM prepared from selected bacteria exhibited antitumour activity. Of note, LC-MS results indicated the presence of several molecules with reported antitumour activity, namely, 3-butylidene-7-hydroxyphthalide, C75, enigmol, estrone 16-oxime, proglumide and S-allyl-L-cysteine. Furthermore, 356 potentially novel molecules from juvenile V. salvator and 184 from adult V. salvator were depicted. Thus, the gut microbiota of V. salvator might be considered as a great niche of antitumour molecules; however, further in vitro and in vivo studies are needed to assess the antitumour properties of these molecules.
    Matched MeSH terms: Chromatography, High Pressure Liquid
  14. Arshad A, Ahemad S, Saleem H, Saleem M, Zengin G, Abdallah HH, et al.
    Biomolecules, 2021 01 04;11(1).
    PMID: 33406643 DOI: 10.3390/biom11010053
    Heliotropium is one of the most important plant genera to have conventional folklore importance, and hence is a potential source of bioactive compounds. Thus, the present study was designed to explore the therapeutic potential of Heliotropium crispum Desf., a relatively under-explored medicinal plant species. Methanolic extracts prepared from a whole plant of H. crispum were studied for phytochemical composition and possible in vitro and in silico biological properties. Antioxidant potential was assessed via six different assays, and enzyme inhibition potential against key clinical enzymes involved in neurodegenerative diseases (acetylcholinesterase (AChE) and butyrylcholinesterase (BChE)), diabetes (α-amylase and α-glucosidase), and skin problems (tyrosinase) was assayed. Phytochemical composition was established via determination of the total bioactive contents and reverse phase ultra-high performance liquid chromatography mass spectrometry (RP-UHPLC-MS) analysis. Chemical profiling revealed the tentative presence of 50 secondary metabolites. The plant extract exhibited significant inhibition against AChE and BChE enzymes, with values of 3.80 and 3.44 mg GALAE/g extract, respectively. Further, the extract displayed considerable free radical scavenging activity against DPPH and ABTS radicals, with potential values of 43.19 and 41.80 mg TE/g extract, respectively. In addition, the selected compounds were then docked against the tested enzymes, which have shown high inhibition affinity. To conclude, H. crispum was found to harbor bioactive compounds and showed potent biological activities which could be further explored for potential uses in nutraceutical and pharmaceutical industries, particularly as a neuroprotective agent.
    Matched MeSH terms: Chromatography, High Pressure Liquid
  15. Salahuddin MAH, Ismail A, Kassim NK, Hamid M, Ali MSM
    Food Chem, 2020 Nov 30;331:127240.
    PMID: 32585546 DOI: 10.1016/j.foodchem.2020.127240
    The present study focused on the phytochemical profiling along with evaluation of in vitro antioxidant, α-glucosidase and α-amylase inhibitory activities of various crudes and fractions obtained from Lepisanthes fruticosa (Roxb) Leenh fruit. Ethanolic seed crude extract exhibited the strongest radical scavenging, β-carotene bleaching activity, α-glucosidase inhibition and the highest total phenolic content (TPC). Column chromatography afforded various fractions with fraction M4 being the most potent due to the strongest radical scavenging, β-carotene bleaching, α-glucosidase inhibition and greatest amount of TPC. Liquid chromatography-tandem mass spectrometry (LC-MS/MS) analysis of ethanolic seed crude extract and fraction M4 showed the presence of various phytochemicals with antioxidant and antidiabetic properties, which include mostly flavonoids and tannins. The results may suggest that the ethanolic crude seed extract and its fraction could be an excellent source of bioactive phytochemicals with antioxidant and antidiabetic potential.
    Matched MeSH terms: Chromatography, High Pressure Liquid
  16. Caillaud A, de la Iglesia P, Campàs M, Elandaloussi L, Fernández M, Mohammad-Noor N, et al.
    Toxicon, 2010 Feb-Mar;55(2-3):633-7.
    PMID: 19631680 DOI: 10.1016/j.toxicon.2009.07.016
    Protein phosphatase inhibition assay (PPIA), Neuroblastoma cell-based assay (Neuro-2a CBA) and LC-MS/MS analysis revealed for the first time the production of okadaic acid (OA) by a Prorocentrum rhathymum strain. Low amounts of OA were detected by LC-MS/MS analysis. Inhibition of PP2A activity and a weak toxicity to the Neuro-2a CBA were also observed.
    Matched MeSH terms: Chromatography, High Pressure Liquid
  17. Sim SM, Back DJ, Breckenridge AM
    Br J Clin Pharmacol, 1991 Jul;32(1):17-21.
    PMID: 1909542
    1. Zidovudine (3'-azido-3'-deoxythymidine; AZT) is the drug of proven efficacy available for the treatment of patients with AIDS or ARC. It is eliminated mainly by hepatic glucuronidation. Therefore, interference with this metabolic pathway may lead to enhancement of AZT effect or to increased toxicity of the drug. We have examined the effect of a number of drugs which themselves undergo glucuronidation on AZT conjugation by human liver microsomes in vitro. 2. AZT glucuronidation followed Michaelis-Menten kinetics. The apparent Km and Vmax values (mean +/- s.d., n = 5), were 2.60 +/- 0.52 mM and 68.0 +/- 23.4 nmol h-1 mg-1, respectively, as determined from Eadie-Hofstee plots. 3. Dideoxyinosine, sulphanilamide and paracetamol were essentially non-inhibitory at concentrations up to 10 mM (4 times the concentration of AZT in the incubation). The most marked inhibitory effects were seen with indomethacin, naproxen, chloramphenicol, probenecid and ethinyloestradiol, with enzyme activity decreased by 97.7, 94.9, 88.7, 83.4% and 79.0%, respectively, at a concentration of 10 mM. Other compounds producing some inhibition of AZT conjugation were oxazepam, salicylic acid and acetylsalicylic acid. 4. Further studies are necessary to characterise the inhibition observed but the method described enables a screen of potentially important drug interactions to be carried out.
    Matched MeSH terms: Chromatography, High Pressure Liquid
  18. Goh CF, Craig DQ, Hadgraft J, Lane ME
    Eur J Pharm Biopharm, 2017 Feb;111:16-25.
    PMID: 27845181 DOI: 10.1016/j.ejpb.2016.10.025
    Drug permeation through the intercellular lipids, which pack around and between corneocytes, may be enhanced by increasing the thermodynamic activity of the active in a formulation. However, this may also result in unwanted drug crystallisation on and in the skin. In this work, we explore the combination of ATR-FTIR spectroscopy and multivariate data analysis to study drug crystallisation in the skin. Ex vivo permeation studies of saturated solutions of diclofenac sodium (DF Na) in two vehicles, propylene glycol (PG) and dimethyl sulphoxide (DMSO), were carried out in porcine ear skin. Tape stripping and ATR-FTIR spectroscopy were conducted simultaneously to collect spectral data as a function of skin depth. Multivariate data analysis was applied to visualise and categorise the spectral data in the region of interest (1700-1500cm(-1)) containing the carboxylate (COO(-)) asymmetric stretching vibrations of DF Na. Spectral data showed the redshifts of the COO(-) asymmetric stretching vibrations for DF Na in the solution compared with solid drug. Similar shifts were evident following application of saturated solutions of DF Na to porcine skin samples. Multivariate data analysis categorised the spectral data based on the spectral differences and drug crystallisation was found to be confined to the upper layers of the skin. This proof-of-concept study highlights the utility of ATR-FTIR spectroscopy in combination with multivariate data analysis as a simple and rapid approach in the investigation of drug deposition in the skin. The approach described here will be extended to the study of other actives for topical application to the skin.
    Matched MeSH terms: Chromatography, High Pressure Liquid
  19. Ahmad K, Win T, Jaffri JM, Edueng K, Taher M
    AAPS PharmSciTech, 2018 Jan;19(1):371-383.
    PMID: 28744617 DOI: 10.1208/s12249-017-0843-9
    This study aims to investigate the use of palm olein as the oil phase for betamethasone 17-valerate (BV) emulsions. The physicochemical properties of the formulations were characterized. In vitro drug release study was performed with the Hanson Vertical Diffusion Cell System; the samples were quantified with HPLC and the results were compared with commercial products. Optimized emulsion formulations were subjected to stability studies for 3 months at temperatures of 4, 25, and 40°C; the betamethasone 17-valerate content was analyzed using HPLC. The formulations produced mean particle size of 2-4 μm, viscosities of 50-250 mPa.s, and zeta potential between -45 and -68 mV. The rheological analyses showed that the emulsions exhibited pseudoplastic and viscoelastic behavior. The in vitro release of BV from palm olein emulsion through cellulose acetate was 4.5 times higher than that of commercial products and more BV molecules deposited in rat skin. Less than 4% of the drug was degraded in the formulations during the 3-month period when they were subjected to the three different temperatures. These findings indicate that palm olein-in-water emulsion can be an alternative vehicle for topical drug delivery system with superior permeability.
    Matched MeSH terms: Chromatography, High Pressure Liquid
  20. Saiman MZ, Mustafa NR, Verpoorte R
    Methods Mol Biol, 2018;1815:437-455.
    PMID: 29981141 DOI: 10.1007/978-1-4939-8594-4_31
    The plant Catharanthus roseus is a rich source of terpenoid indole alkaloids (TIA). Some of the TIA are important as antihypertensive (ajmalicine) and anticancer (vinblastine and vincristine) drugs. However, production of the latter is very low in the plant. Therefore, in vitro plant cell cultures have been considered as a potential supply of these chemicals or their precursors. Some monomeric alkaloids can be produced by plant cell cultures, but not on a level feasible for commercialization, despite extensive studies on this plant that deepened the understanding of the TIA biosynthesis and its regulation. In order to analyze the metabolites in C. roseus cell cultures, this chapter presents the method of TIA, carotenoids, and phytosterols analyses. Furthermore, an NMR-based metabolomics approach to study C. roseus cell culture is described.
    Matched MeSH terms: Chromatography, High Pressure Liquid
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