Author(s): Zhu QY, Hammerstone JF, Lazarus SA, Schmitz HH, Keen CL
Cocoa flavanols and procyanidins have numerous biological activities. It is known that (-)-epicatechin, (+)-catechin, epicatechin-(4beta-8)-epicatechin (dimer B2), and epicatechin-(4beta-6)-epicatechin (dimer B5) are unstable at physiologic pH, degrading almost completely within several hours, whereas they are relatively stable at pH 5.0. The present study investigated the effects of ascorbic and citric acid on the stability of monomers and dimers in simulated intestinal juice (pH 8.5) and in sodium phosphate buffer (pH 7.4). The addition of ascorbic acid to the incubation mixture significantly increased the stability of the monomers and dimers, whereas the addition of citric acid provided no protective effects. LC-MS showed that with the degradation of dimer B2 and dimer B5, doubly linked A-type dimers were formed. The present results, although not directly transferable to in vivo conditions, suggest that ascorbic acid may stabilize cocoa flavanols and procyanidins in the intestine where the pH is neutral, or alkaline, before absorption.
Referred From: https://www.ncbi.nlm.nih.gov/pubmed/12537465
Author(s): Azhar I, Lee, MT
Author(s): Azizah O, Amin I, Nawalyah AG, Ilham A
Author(s): Kim A, Keeny PG
Author(s): María Elena CMF, Soengas P, Velasco P, et al.
Author(s): Perona JS, Cabello-Moruno R, Ruiz-Gutierrez V
Author(s): Halliwell B, Gutteridge JMC
Author(s): Allaith AAA
Author(s): Amin I, Zamaliah MM, Chin WF
Author(s): Dreosti IE
Author(s): Gasser P, Lati E, Peno-Mazzarino L, Bouzoud D, Allegaert L, et al.
Author(s): Young HK, Chan BC, Jin GK, Kang IK, Sun HP, et al.
Author(s): Yang HH, Eun YJ, Dong ON, Hyung JS
Author(s): Hammerstone JF, Lazarus SA, Mitchell AE, Rucker R, Schmitz HH
Author(s): Singleton VL, Rossi JA
Author(s): Benzie IF, Strain JJ
Author(s): Weingarten H, Feder J
Author(s): Prasad NK, Divakar S, Shivamurthy GR, Aradhya SM
Author(s): Meda A, Lamien CE, Romito M, MillogoJ, Nacoulma OG
Author(s): Chang ST, Wu JH, Wang SY, Kang PL, Yang NS, et al.
Author(s): Nelson BC, Sharpless KE
Author(s): Misnawi,Jinap S, Nazamid S, Jamilah B
Author(s): Nazaruddin R, Seng LK, Hassan O, Said M
Author(s): Jinap S, Dimick PS,Hollender R
Author(s): Azizah O, Abbe MMJ, Kong, KW, Amin I, Nawalyah AG, Ilham A
Author(s): Demina NS, Lysenko SV
Author(s): Kim Y, UyamaH, Kobayashi S
Author(s): Miao YP, Wen R, Aoshima H, Zhou PG
Author(s): An BJ, Kwak JH, Park JM, Lee JY, Park TS, et al.
Author(s): BaylacS, Racine P
Author(s): Madhan B, Krishnamoorthy G, Rao JR, Nair BU
Author(s): Thring TS, Hili P, Naughton DP
Author(s): Meyer W, Neurand K, Radke B
Author(s): Gil MI, Tomas-Barberan FA, Hess-Pierce B, Kader AA
Author(s): Sun T, Ho CT
Author(s): Gorinstein S, Lojek A, Ciz M, Pawelzik E, Delgado-Licon E, et al.
Author(s): Gardner PT, White TAC, McPhail DB, Duthie GG