Procyanidin dimer

The method of Kato and Nakai (27) for determining protein surface hydrophobicity was adapted for evaluating procyanidin binding to BSA and Gl. The procedure is based on the fact that the fluorescence quantum yield of cis-parinaric acid increases 40-fold when cis-parinaric acid enters a hydrophobic environment from a hydrophilic environment. The digestion of BSA by trypsin in the presence of procyanidin dimer, procyanidin trimer and black bean procyanidin polymer was evaluated by discontinuous sodium dodecyl sulfate (SDS) slab gel electrophoresis and a picryl sulfonic acid (TNBS) assay (28). 

Thermodynamic analysis of the binding constants of BSA and procyanidin dimer and trimer from the Van t Hoff equation (29) indicates a reaction with a positive entropy change, a positive... 

Trimeric procyanidin binds more tightly to BSA than dimeric procyanidin (Table II). Partition coefficients of dimeric and trimeric catechin between n-octanol and water indicate procyanidin trimer is more hydrophobic than procyanidin dimer. Increased binding constants of trimer relative to dimer agree with reported partition coefficients. Surface hydrophobicity assays with cis-parinaric acid confirm the thermodynamic analysis that binding of procyanidin to BSA is hydrophobic. 

Figure 6. Fluorescence of G1 (0.04%), procyanidin dimer and cis-parinaric acid.

Fig. 3.1 Structures of (a) catechin, (b) epicatechin, (c) epicatechin gallate, (d) general structure of PAs, and (e) procyanidin dimer...

Ricardo DS, Rigaud JM, Cheynier V et al (1991) Procyanidin dimers and trimers from grape seeds. Phytochemistry 30 1259-1264... 

The NOESY experiment has also been very useful for revealing the presence of rotational conformers of dimeric flavonoids and flavone C-glycosides (Figure 2.3). Strong exchange crosspeaks between equivalent protons of each conformer revealed the rotational equilibriums. This NOE phenomenon was first noted by Hatano et al. in two conformers of procyanidin dimers. The volume of the NOESY crosspeaks is related to the distance... 

A-Type malvidin 3-glc-procyanidin dimer (5 12) Red wine extract 1071 ([M+HD HPLC-ESI-Q-MS 87 3... 

Recent studies performed using this method have shown that flavanol bitterness decreases from monomer to trimer. Epicatechin was perceived more bitter than catechin and the C4-C6-linked catechin dimer more bitter than other procyanidin dimers with C4-C6 linkages. This may be due to the higher lipophilic character of these molecules facilitating their diffusion to the gustatory receptor. Bitterness of procyanidin fractions in 5% ethanol decreased with their... 

Spencer JP, Schroeter H, Shenoy B, Srai SK, Debnam ES, Rice-Evans C. 2001b. Epicatechin is the primary bioavailable form of the procyanidin dimers B2 and B5 after transfer across the small intestine. Biochem Biophys Res Commun 285 588-593. 

Holt RR, Lazarus SA, Sullards MC, Zhu QY, Schramm DD, Hammerstone JF, Fraga CG, Schmitz HH, Keen CL. 2002. Procyanidin dimer B2 [epicatechin-(4beta-8)-epicatechin] in human plasma after the consumption of a flavanol-rich cocoa. Am J Clin Nutr 76 798-804. 

Another membrane property physically affected by flavonoids is the surface potential. Working with liposomes composed of PC and PS, we found that (—)-epicatechin and certain procyanidins (dimer to hexamer) decreased liposome surface potential. This effect relied on both, procyanidin concentration and number of monomeric units [Verstraeten et al., 2003]. On the other hand, when liposomes were composed exclusively of PC, it was found that (—)-epi-catechin dimers Al and B2, and the trimers A and C2 increased liposome surface potential in a concentration-dependent manner [Verstraeten et al.,... 

Similar to hydrophilic flavonoids, hydrophobic flavonoids can affect membrane permeability. Alterations in this biophysical property of liposome bilayers lead to the release of bulky molecules entrapped into the inner aqueous space. As mentioned in the previous section, a strong correlation was found between flavonoid retention to a hydrophobic matrix and their capacity to induce membrane leakage [Ollila et al., 2002]. Interestingly, hydrophilic flavonoids, such as (—)-epicatechin and related procyanidins (dimer to hex-amer) prevented Fe2 + -mediated liposome permeabilization, although in this case the beneficial effect could be related to both their antioxidant and metal chelating capacities and their membrane stabilizing properties [Verstraeten et al., 2004],... 

Verstraeten SV, Hammerstone JF, Keen CL, Fraga CG, Oteiza PI. 2005. Antioxidant and membrane effects of procyanidin dimers and trimers isolated from peanut and cocoa. J Agric Food Chem 53 5041-5048. 

Procyanidin B3 (= Catechin (4a —>8) catechin) (procyanidin dimer) Procyanidin B4 (catechin (4a — 8)epicatechin) (procyanidin dimer) Tellimagrandin I (= 4,5 Hexahydroxydiphenoyl 2,3-digalloylglucose) (ellagitannin)... 

Procyanidin B4 (catechin (4a—>8) epicatechin) (procyanidin dimer) Rugosin D (ellagitannin)... 

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