TY - JOUR
T1 - Comparing the Chemistry of Malvidin-3-O-glucoside and Malvidin-3,5-O-diglucoside Networks
T2 - A Holistic Approach to the Acidic and Basic Paradigms with Implications in Biological Studies
AU - Seco, André
AU - Pereira, Ana Rita
AU - Camuenho, Ambrósio
AU - Oliveira, Joana
AU - Dias, Ricardo
AU - Brás, Natércia F.
AU - Basílio, Nuno
AU - Parola, A. Jorge
AU - Lima, João C.
AU - de Freitas, Victor
AU - Pina, Fernando
N1 - Publisher Copyright:
© 2024 The Authors. Published by American Chemical Society.
This work was supported by the Associate Laboratory forGreen Chemistry - LAQV (LA/P/0008/2020 DOI 10.54499/LA/P/0008/2020; UIDP/50006/2020 DOI 10.54499/UIDP/50006/2020; UIDB/50006/2020 DOI 10.54499/UIDB/50006/2020) which is financed by national funds fromFCT/MCTES and by the AgriFood XXI I&D&I project(NORTE-01-0145-FEDER-000041) cofinanced by EuropeanRegional Development Fund (ERDF), through the NORTE2020 (Programa Operacional Regional do Norte 2014/2020and Portuguese NMR Network (ROTEIRO/0031/2013-PINFRA/22161/2016). Authors thank FCT/MCTES forresearch contracts CEECIND/00466/2017 (N.B.), CEE-CIND/02017/2018 (N.F.B.), and CEEC 2022.00042.CEE-CIND/CP1724/CT0017 (J.O.); Ph.D. fellowships2020.07313.BD (A.S.) and SFRH/BD/146549/2019(A.R.P.); Gulbenkian Foundation grant no 219201 and Meritgrant 2020�INAGBE, Angola (AC).
PY - 2024/4/3
Y1 - 2024/4/3
N2 - The kinetics, thermodynamics, and degradation of malvidin mono- and diglucosides were studied following a holistic approach by extending to the basic medium. In acidic conditions, the reversible kinetics of the flavylium cation toward the equilibrium is controlled by the hydration and cis-trans isomerization steps, while in the basic medium, the OH- nucleophilic addition to the anionic quinoidal bases is the slowest step. There is a pH range (transition pHs), between the acidic and basic paradigms, that includes physiological pH (7.4), where degradation reactions occur faster, preventing the system from reaching the equilibrium. The transition pH of the diglucoside is narrower, and in contrast with the monoglucoside, there is no evidence for the formation of colored oligomers among the degradation products. Noteworthy, OH- addition in position 4 to form B42-, a kinetic product that decreases the overall equilibration rate, was observed only for the diglucoside.
AB - The kinetics, thermodynamics, and degradation of malvidin mono- and diglucosides were studied following a holistic approach by extending to the basic medium. In acidic conditions, the reversible kinetics of the flavylium cation toward the equilibrium is controlled by the hydration and cis-trans isomerization steps, while in the basic medium, the OH- nucleophilic addition to the anionic quinoidal bases is the slowest step. There is a pH range (transition pHs), between the acidic and basic paradigms, that includes physiological pH (7.4), where degradation reactions occur faster, preventing the system from reaching the equilibrium. The transition pH of the diglucoside is narrower, and in contrast with the monoglucoside, there is no evidence for the formation of colored oligomers among the degradation products. Noteworthy, OH- addition in position 4 to form B42-, a kinetic product that decreases the overall equilibration rate, was observed only for the diglucoside.
KW - anthocyanins
KW - degradation rates
KW - kinetics
KW - malvidin monoglucoside and diglucoside
KW - malvidin monoglucoside dimers
KW - physiologic pH
KW - stopped-flow
UR - http://www.scopus.com/inward/record.url?scp=85188842684&partnerID=8YFLogxK
U2 - 10.1021/acs.jafc.4c00552
DO - 10.1021/acs.jafc.4c00552
M3 - Article
C2 - 38520401
AN - SCOPUS:85188842684
SN - 0021-8561
VL - 72
SP - 7497
EP - 7510
JO - Journal of Agricultural and Food Chemistry
JF - Journal of Agricultural and Food Chemistry
IS - 13
ER -