Reversed-phase HPLC study on the in vitro enzymic degradation of dermorphin

Peptides ◽  
1986 ◽  
Vol 7 (2) ◽  
pp. 247-251 ◽  
Author(s):  
S. Scalia ◽  
S. Salvadori ◽  
M. Marastoni ◽  
F. Bortolotti ◽  
R. Tomatis
Keyword(s):  
Reversed Phase ◽  
Reversed Phase Hplc ◽  
Hplc Study

scholarly journals A Reversed-phase HPLC Study of the Complexation of Benzene Derivatives Guest Molecules with 5,17-bis(N-Tolyliminomethyl)-25,27-dipropoxycalix[4]arene in Acetonitrile–Water Solution

1999 ◽  
Vol 23 (1) ◽  
pp. 60-61
Author(s):  
O. I. Kalchenko ◽  
A. V. Solovyov ◽  
J. Lipkowski ◽  
V. I. Kalchenko
Keyword(s):  
Stability Constants ◽  
Water Solution ◽  
Reversed Phase ◽  
Benzene Derivatives ◽  
Reversed Phase Hplc ◽  
Guest Molecules ◽  
Hplc Study

Stability constants of the host–guest complexes of 5,17-bis( N-tolyliminomethyl)-25,27-dipropoxycalix[4]arene with benzene derivatives were determined by reversed-phase HPLC in acetonitrile–water solution.

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.

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.

Detection of phospholipid oxidation in oxidatively stressed cells by reversed-phase HPLC coupled with positive-ionization electroscopy MS

2001 ◽  
Vol 355 (2) ◽  
pp. 449-457 ◽  
Author(s):  
Corinne M. SPICKETT ◽  
Nicola RENNIE ◽  
Helen WINTER ◽  
Laura ZAMBONIN ◽  
Laura LANDI ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Mammalian Cells ◽  
Cultured Cells ◽  
Direct Injection ◽  
Biological Tissues ◽  
Reversed Phase ◽  
Membrane Lipid ◽  
Oxidized Phospholipids ◽  
Reversed Phase Hplc

Measurement of lipid peroxidation is a commonly used method of detecting oxidative damage to biological tissues, but the most frequently used methods, including MS, measure breakdown products and are therefore indirect. We have coupled reversed-phase HPLC with positive-ionization electrospray MS (LC-MS) to provide a method for separating and detecting intact oxidized phospholipids in oxidatively stressed mammalian cells without extensive sample preparation. The elution profile of phospholipid hydroperoxides and chlorohydrins was first characterized using individual phospholipids or a defined phospholipid mixture as a model system. The facility of detection of the oxidized species in complex mixtures was greatly improved compared with direct-injection MS analysis, as they eluted earlier than the native lipids, owing to the decrease in hydrophobicity. In U937 and HL60 cells treated in vitro with t-butylhydroperoxide plus Fe2+, lipid oxidation could not be observed by direct injection, but LC-MS allowed the detection of monohydroperoxides of palmitoyl-linoleoyl and stearoyl-linoleoyl phosphatidylcholines. The levels of hydroperoxides observed in U937 cells were found to depend on the duration and severity of the oxidative stress. In cells treated with HOCl, chlorohydrins of palmitoyloleoyl phosphatidylcholine were observed by LC-MS. The method was able to detect very small amounts of oxidized lipids compared with the levels of native lipids present. The membrane-lipid profiles of these cells were found to be quite resistant to damage until high concentrations of oxidants were used. This is the first report of direct detection by LC-MS of intact oxidized phospholipids induced in cultured cells subjected to oxidative stress.

scholarly journals Autolysis and related proteolysis in Swiss cheese for two Lactobacillus helveticus strains

2000 ◽  
Vol 67 (2) ◽  
pp. 261-271 ◽  
Author(s):  
FLORENCE VALENCE ◽  
STÉPHANIE-MARIE DEUTSCH ◽  
ROMAIN RICHOUX ◽  
VALÉRIE GAGNAIRE ◽  
SYLVIE LORTAL
Keyword(s):  
Streptococcus Thermophilus ◽  
Reversed Phase ◽  
Lactobacillus Helveticus ◽  
Small Scale ◽  
Propionibacterium Freudenreichii ◽  
Reversed Phase Hplc ◽  
Peptide Hydrolysis ◽  
Similar Extent ◽  
Cold Room

Intracellular peptidases of Lactobacillus helveticus may play a major role in the proteolysis of Swiss cheeses, provided that they are released through bacterial lysis. Experimental Swiss cheeses were manufactured on a small scale from thermized and microfiltered milk using as starters (in addition to Streptococcus thermophilus and Propionibacterium freudenreichii) one of two Lb. helveticus strains, ITGLH1 and ITGLH77, which undergo lysis to different extents in vitro. All the cheeses were biochemically identical after pressing. The viability of Lb. helveticus ITGLH1 and ITGLH77 decreased to a similar extent (96–98%) while in the cold room, but the concomitant release of intracellular lactate dehydrogenase in cheeses made with strain ITGLH1 was 5–7-fold that in cheeses made with ITGLH77. Protein profiles and immunoblot detection of the dipeptidase PepD confirmed a greater degree of lysis of the ITGLH1 strain. Free active peptidases were detected in aqueous extracts of cheese for both strains, and proteolysis occurred principally in the warm room. Reversed-phase HPLC revealed a more extensive peptide hydrolysis for ITGLH1, which was confirmed by the greater release of free NH2 groups (+33%) and free amino acids (+75%) compared with ITGLH77. As the intracellular peptidase activities of ITGLH1 and ITGLH77 have previously been shown to be similar, our results indicated that the extent of lysis of Lb. helveticus could have a direct impact on the degree of proteolysis in Swiss cheeses.

scholarly journals A reversed phase HPLC study of diastereoisomer derivatization methods for chiral separation of carboxylic drugs.

1994 ◽  
Vol 43 (12) ◽  
pp. 1201-1204 ◽  
Author(s):  
Takashi ARAI ◽  
Mitsunori ICHINOSE ◽  
Noriyuki NIMURA ◽  
Toshio KINOSHITA
Keyword(s):  
Chiral Separation ◽  
Reversed Phase ◽  
Reversed Phase Hplc ◽  
Hplc Study
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