scholarly journals Isolation and identification of a C39 demethylated metabolite of rapamycin from pig liver microsomes and evaluation of its immunosuppressive activity

1998 ◽  
Vol 44 (3) ◽  
pp. 532-538 ◽  
Author(s):  
Marc J M Nickmilder ◽  
Dominique Latinne ◽  
Jean-Paul De Houx ◽  
Roger K Verbeeck ◽  
Georges J J Lhoëst
Keyword(s):  
Parent Compound ◽  
Liver Microsomes ◽  
Reversed Phase ◽  
Reversed Phase Hplc ◽  
Immunosuppressive Activity ◽  
Isolation And Identification ◽  
Fk 506 ◽  
Pig Liver ◽  
Structural Modifications

Abstract We studied in vitro metabolism of rapamycin using pig liver microsomes. After extraction of the metabolites from the incubation medium, the crude metabolite extract was submitted to normal and subsequently to reversed-phase HPLC chromatography. We describe in the current study a metabolite of retention time 23.2 min collected from reversed-phase HPLC and identified by fast atom bombardment mass spectrometry (MS) and electrospray MS-MS as a C39 demethylated rapamycin metabolite. In vitro immunosuppressive activity of this metabolite, determined by the mixed lymphocyte reaction, was negligible compared with that of the parent compound. The decrease of in vitro immunosuppressive activity compared with the parent compound is likely to be attributed to important structural modifications of the rapamycin binding region to the FK-506 binding protein.

15-Desmethyl FK-506 and 15,31-desmethyl FK-506 from human liver microsomes: isolation, identification (by fast atom bombardment mass spectrometry and NMR), and evaluation of in vitro immunosuppressive activity

1994 ◽  
Vol 40 (5) ◽  
pp. 740-744 ◽  
Author(s):  
G J Lhöest ◽  
N Maton ◽  
D Latinne ◽  
A Laurent ◽  
R K Verbeeck
Keyword(s):  
Mass Spectrometry ◽  
Human Liver ◽  
Fast Atom Bombardment ◽  
Liver Microsomes ◽  
Reversed Phase ◽  
Human Liver Microsomes ◽  
Resonance Spectroscopy ◽  
Immunosuppressive Activity ◽  
Fk 506

Abstract 15-Desmethyl FK-506 and 15,31-desmethyl FK-506 metabolites extracted from incubated human liver microsomes were separated by normal and reversed-phase HPLC. The metabolites were identified by fast atom bombardment/mass spectrometry and nuclear magnetic resonance spectroscopy. The in vitro 50% inhibitory concentration, tested against bidirectional mixed lymphocyte reactions, was 325 mg/L for 15,31-desmethyl FK-506 and 4 mg/L for 15-desmethyl FK-506, indicating that these products of FK-506 demethylation retain in vitro immunosuppressive activity.

Characterization of Highly Polar Dna Adducts Derived from Dibenz[A,H]Anthracene (DBA), 3,4-Dihydroxy-3,4-Dihydro-DBA, and 3,4,10,11-Tetrahydroxy-3,4,10,11-Tetrahydro-DBA

1993 ◽  
Vol 9 (3) ◽  
pp. 503-509 ◽  
Author(s):  
Juergen Fuchs ◽  
Jiri Mlcoch ◽  
Franz Oesch ◽  
Karl Ludwig Platt
Keyword(s):  
Dna Adducts ◽  
Liver Microsomes ◽  
Metabolic Activation ◽  
Reversed Phase ◽  
Reversed Phase Hplc ◽  
Sprague Dawley ◽  
Sprague Dawley Rats ◽  
Calf Thymus

Two highly polar DNA adducts were found after metabolic activation of 3,4,10,11-tetrahydroxy-3,4,10,11-tetrahydrodibenz[ a,h]anthracene(DBA-3,4;10, 11-bisdiol) by liver microsomes isolated from male Sprague-Dawley rats pretreated with Aroclor 1254 in presence of calf thymus DNA. These DNA adducts could be assigned to the metabolites of dibenz[ a,h]anthracene (DBA), of 3R,4R,10R,11R-tetrahydroxy-3,4,10,11-tetrahydro-DBA and of 3R,4R,10S,US-tetrahydroxy-3,4,10,11-tetrahydro-DBA. DNA adducts derived from metabolites of 3S,4S,10S,11S-tetrahydroxy-3,4,10,11-tetrahydro-DBA were not found. These highly polar adducts also could be detected by reversed phase HPLC after incubation of dibenz[ a,h]anthracene, 3R,4R-dihydroxy-3,4-dihydro-DBA ((-)-DBA-3,4-diol) and 3S,4S- dihydroxy-3,4-dihydro-DBA ((+)-DBA-3,4-diol) with DNA in presence of the activating system. After incubation of 14C labelled DBA DNA adducts derived from DBA-3,4;10,11-bisdiol were found in a fraction of 38% and bay region 3,4-dihydroxy-1,2-epoxy-1,2,3,4-tetrahydro-DBA-DNA adducts at a level of 25%. DBA-3,4; 10,11-bisdiol exhibited a higher DNA binding yield (38 × 12 pmollmg DNA) than (-)-DBA-3,4-diol (23 × 6 pmol/mg DNA), the most mutagenic 3,4-diol enantiomer. For (+)-DBA-3,4-diol the highly polar DNA adducts derived from DBA-3,4;10,11-bisdiol were by far the most predotmnant adducts in vitro.

Isolation and Identification of Peptidic α-Glucosidase Inhibitors Derived from Sardine Muscle Hydrolyzate

1999 ◽  
Vol 54 (3-4) ◽  
pp. 259-263 ◽  
Author(s):  
Toshiro Matsui ◽  
Tomoyuki Oki ◽  
Yutaka Osajima
Keyword(s):  
Reversed Phase ◽  
Peptide Chain ◽  
Amide Proton ◽  
Inhibition Activity ◽  
Reversed Phase Hplc ◽  
Isolation And Identification ◽  
Inhibitory Peptides ◽  
Glucosidase Inhibitors ◽  
C Terminus ◽  
Column Eluate

Abstract We report here the isolation of a-glucosidase (AGH) inhibitory peptides derived from sardine muscle hydrolyzate, which was prepared by digestion with Bacillus licheniformis alka­line protease. As a result of reversed-phase HPLC purification, two AGH inhibitory peptides were isolated from a DEAE -Sephadex A-25 column eluate. The peptides were identified as follows: Val-Trp (IC50 = 22.6 mᴍ) and Try -Tyr -Pro -Leu (IC50 = 3.7 mᴍ). AGH inhibitory studies of Try -Tyr -Pro -Leu and its derivatives demonstrated the importance of the tri-peptide chain length as well as the hydrophobic aromatic amino acid tyrosine at the N-terminus, aliphatic amino acids at the C-terminus, as well as an amide proton from the peptide chain at the middle position of the tri-peptide to develop AGH inhibition activity.

Characterization of in vitro proteolytic processing of β-endorphin by reversed-phase HPLC

Peptides ◽  
1984 ◽  
Vol 5 (6) ◽  
pp. 1037-1042 ◽  
Author(s):  
Thomas P. Davis ◽  
Hans Schoemaker ◽  
Alison J. Culling-Berglund
Keyword(s):  
Reversed Phase ◽  
Proteolytic Processing ◽  
Reversed Phase Hplc

Comparative Profiling of Four Lignans (Phyllanthin, Hypophyllanthin, Nirtetralin, and Niranthin) in Nine Phyllanthus Species from India Using a Validated Reversed Phase HPLC-PDA Detection Method

2020 ◽  
Author(s):  
Jinal Patel ◽  
Padamnabhi Shanker Nagar ◽  
Kalpana Pal ◽  
Raghuraj Singh ◽  
Tushar Dhanani ◽  
...  
Keyword(s):  
Reversed Phase ◽  
Reversed Phase Hplc ◽  
Extraction Solvent ◽  
Plant Parts ◽  
Commercial Cultivation ◽  
Wide Range ◽  
Development And Validation ◽  
Herbal Formulations

Abstract Background Phyllanthus species exhibit a wide range of in vitro and in vivo pharmacological activities; however, little is known about the compounds present in the extracts that are responsible for such actions. Objective Development and validation of a simple reversed phase HPLC-PDA method for profiling of phyllanthin, hypophyllanthin, nirtetralin, and niranthin in extracts of Phyllanthus species was carried out. Methods Separation was achieved using an XBridge column® (150 × 4.6 mm, 5.0 µm id) in an isocratic elution mode with mobile phase comprising of a mixture of acetonitrile and water with TFA (0.05%, v/v, pH = 2.15) at ambient temperature with a flow rate of 1 mL/min. Results Phyllanthin, hypophyllanthin, nirtetralin, and niranthin were eluted at mean retention times of 10.47, 11.10, 13.67, and 14.53 min, respectively. LOD and LOQ for all four analytes were 0.75 and 3.00 μg/mL, respectively. RSDr values for intraday and interday precision for phyllanthin, hypophyllanthin, nirtetralin, and niranthin were 0.38–1.32 and 0.45–1.77%; 0.22–3.69 and 0.24–3.04%, 0.73–2.37 and 0.09–0.31%, and 1.56–2.77 and 0.12–0.68%, respectively. Conclusions The developed and validated HPLC-PDA method was applied for identification and quantification of phyllanthin, hypophyllanthin, nirtetralin, and niranthin in extracts of different plant parts of selected Phyllanthus species. The outcome of the present investigation could be useful for selection of best species to promote its commercial cultivation and suitable extraction solvent for preparation of lignan-enriched fractions. This HPLC-PDA method could be useful for quality control of herbal formulations containing plants from Phyllanthus species.

scholarly journals Safety Assessment of Compounds after In Vitro Metabolic Conversion Using Zebrafish Eleuthero Embryos

2019 ◽  
Vol 20 (7) ◽  
pp. 1712 ◽  
Author(s):  
Arianna Giusti ◽  
Xuan-Bac Nguyen ◽  
Stanislav Kislyuk ◽  
Mélanie Mignot ◽  
Cecilia Ranieri ◽  
...  
Keyword(s):  
High Performance ◽  
Safety Assessment ◽  
Parent Compound ◽  
Liver Microsomes ◽  
Toxicity Testing ◽  
Rat Liver Microsomes ◽  
Metabolic Conversion ◽  
Toxic Potential

Zebrafish-based platforms have recently emerged as a useful tool for toxicity testing as they combine the advantages of in vitro and in vivo methodologies. Nevertheless, the capacity to metabolically convert xenobiotics by zebrafish eleuthero embryos is supposedly low. To circumvent this concern, a comprehensive methodology was developed wherein test compounds (i.e., parathion, malathion and chloramphenicol) were first exposed in vitro to rat liver microsomes (RLM) for 1 h at 37 °C. After adding methanol, the mixture was ultrasonicated, placed for 2 h at −20 °C, centrifuged and the supernatant evaporated. The pellet was resuspended in water for the quantification of the metabolic conversion and the detection of the presence of metabolites using ultra high performance liquid chromatography-Ultraviolet-Mass (UHPLC-UV-MS). Next, three days post fertilization (dpf) zebrafish eleuthero embryos were exposed to the metabolic mix diluted in Danieau’s medium for 48 h at 28 °C, followed by a stereomicroscopic examination of the adverse effects induced, if any. The novelty of our method relies in the possibility to quantify the rate of the in vitro metabolism of the parent compound and to co-incubate three dpf larvae and the diluted metabolic mix for 48 h without inducing major toxic effects. The results for parathion show an improved predictivity of the toxic potential of the compound.

Sign in / Sign up

Export Citation Format

Share Document