Biomedical subjects

Sławomir Wybraniec

Publications and source records attributed to Sławomir Wybraniec.

8 recordsLinked to original sources

PubMed2006

Minor betalains in fruits of Hylocereus species.

Betacyanins in peel and flesh of fruits of different Hylocereus species were identified by means of GC/MS, electrospray MS/MS, HPLC as well as (1)H and (13)C NMR techniques. As hitherto unknown pigments: betanidin 5-O-(2'-O-beta-D-apiofuranosyl)-beta-D-glucopyranoside, betanidin 5-O-(4'-O-malonyl)-beta-D-glucopyranoside and betanidin 5-O-[(5''-O-E-sinapoyl)-2'-O-beta-D-apiofuranosyl]-beta-D-glucopyranoside were elucidated. The sinapoyl moiety attachment position in the structure of betacyanins was established for the first time. The peel contained a more complex pattern of betacyanins with apiofuranosyl moiety. Other recently identified pigments were also present in the samples and their (1)H or (13)C NMR spectra were recorded. In the case of phyllocactin and its 4'-isomer the migration of the malonyl group was noticed.

Betalains↗

PubMed2006

Effect of tetraalkylammonium salts on retention of betacyanins and decarboxylated betacyanins in ion-pair reversed-phase high-performance liquid chromatography.

The ability of tetraalkylammonium salts to act as ion-pairing agents for betacyanins and mono- as well as bidecarboxylated betacyanins in HPLC on reversed phase is reported. The results indicate substantial and various influences of tetraalkylammonium salt addition to eluent on magnitude and direction of retention time changes of the analytes. The interactions of the tetraalkylammonium cations with the accessible positive and negative charged parts of the analysed molecules at their different level and position of decarboxylation determined the possibility of ion-pair formation. A remarkable positive influence was observed for betacyanins on the basis of strongly enhanced retention of the resulted ion-pairs. In contrast, the 2,17-bidecarboxy-betacyanin retention, in most of the applied conditions, strongly decreased under the impact of the reagents. The effect of the salt concentration on direction of 17-decarboxy-betacyanin and 2,17-bidecarboxy-betacyanin retention changes strongly varied with the eluent pH. The carboxylic group at the C-2 carbon cannot interact with tetraalkylammonium cations as strongly as does the C-17 carboxylic group, leading to different effects in the absence of carboxylic group at the C-2 or C-17 carbon in the molecules.

Betacyanins↗

PubMed2005

Generation of decarboxylated and dehydrogenated betacyanins in thermally treated purified fruit extract from purple pitaya (Hylocereus polyrhizus) monitored by LC-MS/MS.

Pigments of purple pitaya [Hylocereus polyrhizus (F.A.C. Weber) Britton and Rose] fruits were submitted to extraction and were decarboxylated during heating experiments in acidified ethanolic and aqueous solutions. Groups of betacyanins with different decarboxylation levels were identified in the heating products by LC-DAD and LC-MS/MS. The main decarboxylation products were 2-decarboxy-betacyanins, 17-decarboxy-betacyanins, and 2,17-bidecarboxy-betacyanins. The structures of other compounds were assigned to 2,15,17-tridecarboxy-betacyanins and 14,15-dehydrogenated derivatives (neo-derivatives) of all decarboxylated betacyanins found.

Cactaceae↗

PubMed2005

Formation of decarboxylated betacyanins in heated purified betacyanin fractions from red beet root (Beta vulgaris L.) monitored by LC-MS/MS.

Mixtures of mono-, bi-, and tridecarboxylated betacyanins together with their corresponding neobetacyanins obtained from Beta vulgaris L. root juice as heating degradation products of betacyanins were identified by high-performance liquid chromatography with tandem mass spectrometry (LC-MS/MS) and diode-array (LC-DAD) detection. Two monodecarboxy-betacyanin pairs of diastereomers were detected after the decarboxylation in ethanolic and aqueous solutions. Generation of 17-decarboxy-betacyanins and 2-decarboxy-betacyanins was suggested, the latter so far never having been attributed to betacyanin thermal degradation products. Other main products of decarboxylation were 2,17-bidecarboxybetanin, its isoform, and 14,15-dehydrogenated (neobetacyanin) derivatives of all the decarboxylated betacyanins. The results of this research are crucial in determining betacyanin degradation mechanisms in juices or extracts of B. vulgaris L. roots and other products containing these pigments.

Beta vulgaris↗

PubMed2004

Influence of perfluorinated carboxylic acids on ion-pair reversed-phase high-performance liquid chromatographic separation of betacyanins and 17-decarboxy-betacyanins.

The ability of trifluoroacetic acid, pentafluoropropionic acid and heptafluorobutyric acid to act as ion-pairing agents for betacyanins and 17-decarboxy-betacyanins during HPLC analysis on a Luna C18(2) reversed-phase column is reported. While the perfluorinated carboxylic acids affect the retention of both groups of compounds by changing the pH of the mobile phase, the possibility of ion-pair chromatography for 17-decarboxy-betacyanins was noticed. In order to explain the accessibility of the positive charge for the counter-anion in decarboxy-betacyanins, the mesomeric structures of the polymethine system at low pH (around a value of 1.5), when the carboxylic group in the 2 position is protonated, should be taken into consideration.

Betalains↗

PubMed2003

Controlled-release systems for the delivery of cyromazine into water surface.

Controlled-release systems (CRSs) for the insect growth regulator cyromazine (Neporex), as a larvicide against Culex pipiens (Culicidae) mosquitoes, are under development. Despite promising results obtained previously for both in vitro (dissolution tests) and in vivo systems (mosquito larvae floating on water surfaces), it was evident that the CRSs did not remain afloat for sufficiently long times. The present study was thus conducted to determine the relationship between the process parameters and the potential contact time of the active ingredient with the mosquito larvae. A series of CRSs were prepared by an extrusion process, alone or in combination with a supplementary coating. The active ingredient was incorporated into the matrix or the coating. The matrix comprised low-density polyethylene 600 and perlite, and the coating, a polyurea with or without the addition of paraffin wax. The study showed that the cumulative release of the active ingredient into water could be controlled by manipulating the preparation techniques, the types and concentrations of inert materials, and the concentration of the active ingredient.

Animals↗

PubMed2003

Controlled-release systems for the insect growth regulator pyriproxyfen.

A simple technique was developed for the production of controlled-release systems (CRSs) for pyriproxyfen, an insect growth regulator active against the larvae of Culex pipiens, the most common species of mosquito found in developed countries. The CRSs consisted of a spongy core material encapsulated in a coating of a polyurethane or polyurea hydrogel, into which the active ingredient had been incorporated. The coating also included a surfactant to improve the low solubility in water of pyriproxyfen. The light core material enabled the CRS to float on the water surface, where the mosquitoe larvae are found. The type and amount of the polymeric coating and the amount of surfactant influenced the release profiles into water of the active ingredient. The release profiles of the CRSs were adjusted to the life cycle of the C. pipiens mosquito in order to obtain their optimal activity on the eighth day, which corresponds to the time of larval maturity.

Animals↗

PubMed2002

Fruit flesh betacyanin pigments in hylocereus cacti.

Determination of profiles and total contents of betacyanins in cactus fruits of Hylocereus species using chromatographic and spectrophotometric method is described. The investigated species were H. polyrhizus, H. purpusii, H. costaricensis, H. sp. 487 (all red-flesh species and hybrids made among them), and the white- or red-flesh species H. undatus. Hybrids included hybrid 1 (H. undatus white-flesh clone and H. sp. 487), hybrid 35 (H. sp. 487 and H. polyrhizus), and the reciprocal hybrid hybrid 95 (H. polyrhizus and H. sp. 487). Fruits of H. polyrhizus exhibited the highest relative concentration (expressed as percentage of the total HPLC peak area) of hylocerenin, a recently discovered pigment, and a high relative concentration of phyllocactin. Hylocerenin and isohylocerenin, present in fruits at relative concentrations of 11.7 and 5.8%, respectively, are probably responsible for the fluorescent color of the fruit pulp. H. costaricensis fruits have a much higher content of phyllocactin (63.9%), which is almost 4 times higher than the betanin content. These differences in pigment concentrations might explain the differences in red hues of the flesh of these fruits.

Betacyanins↗