Conjugation of oxidized betanidin and gomphrenin pigments from Basella alba L. fruits with glutathione
Authors:
- Agnieszka Kumorkiewicz,
- Edward Szneler,
- Sławomir Wybraniec
Abstract
Formation of glutathionic conjugates with quinonoid forms generated through oxidation of betanidin and gomphrenin obtained from fruits of Basella alba L. was studied by high-performance liquid chromatography coupled with triple quadrupole tandem mass spectrometry (HPLC−DAD−ESI−MS/MS) and ion-trap time-of-flight high-resolution mass spectrometry (LCMS−IT−TOF). The conjugates were studied for the aim of trapping the formed quinonoids by glutathione which would indicate a presence of specific quinonoid structures in reaction products of the pigments with 2,2′-azino-bis(3ethylbenzothiazoline-6-sulfonic acid) (ABTS) cation radicals. The structure of betanidin conjugate, which was formed with high efficiency, was established by NMR analysis. In the case of gomphrenin conjugate, its structure was tentatively indicated as analogous to betanidin conjugate by MSn fragmentation paths. In contrast, no detectable glutathionic conjugate of betanin quinonoid (quinone methide) was present in similar betanin reaction mixtures. As a result of additional experiments performed during oxidation of gomphrenin by ABTS cation radicals in the absence of glutathione, except for decarboxylated and dehydrogenated gomphrenin derivatives, generation of betanidin and its derivatives was observed which indicated that the subsequent dopachromic intermediate rearrangement affected hydrolysis of the glucosidic bond. This is in contrast to betanin which is not deglucosylated in the same conditions during the oxidation. The obtained results shed some light on the oxidation pathways of various glycosylated betacyanins with gomphrenin being presumably the most potent antioxidant ascertained in this group of pigments.
- Record ID
- CUT767cf9ba7dad42a69b38006cd6b23215
- Publication categories
- ;
- Author
- Journal series
- Journal of Agricultural and Food Chemistry, ISSN 0021-8561, e-ISSN 1520-5118
- Issue year
- 2018
- Vol
- 66
- No
- 48
- Pages
- 12815-12826
- Other elements of collation
- schem.; tab.; Bibliografia (na s.) - 12825-12826; Bibliografia (liczba pozycji) - 31; Oznaczenie streszczenia - Abstr.; Numeracja w czasopiśmie - Vol. 66, Iss. 48
- Keywords in English
- glutathione conjugates, trapping agent, betalains, betanidin, gomphrenin, Basella alba, Malabar spinach, mass spectrometry
- DOI
- DOI:10.1021/acs.jafc.8b04941 Opening in a new tab
- URL
- https://pubs.acs.org/doi/10.1021/acs.jafc.8b04941 Opening in a new tab
- Related project
- Badania mechanizmu utleniania pigmentów betacyjanin. . Project leader at PK: , ,
Projects financed by NSC [Projekty finansowane przez NCN] - Language
- eng (en) English
- Score (nominal)
- 45
- Additional fields
- Indeksowana w: Web of Science, Scopus
- Uniform Resource Identifier
- https://cris.pk.edu.pl/info/article/CUT767cf9ba7dad42a69b38006cd6b23215/
- URN
urn:pkr-prod:CUT767cf9ba7dad42a69b38006cd6b23215
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