Trimeric procyanidin

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. 

Sun B, Belchior P, Ricardo-da-SUva JM et al (1999) Isolation and purification of dimeric and trimeric procyanidins from grape seeds. J Chromatogr A 841 115-121... 

The positive-ion mode fragmentation patterns proposed for trimeric procyanidins studied by isolation and ion trap fragmentation of the most intense MS spectra signals, fragmentation of the principal ions of the MS2 spectra, and acquisition of MS3 spectra, are shown in Fig. 6.14 (Pati et al., 2006). In Figs. 6.15 and 6.16, the schemes of positive... 

Figure 6.14. Positive-ion mode fragmentation patterns of trimeric procyanidins. The ESI-MS conditions spray voltage 4.5 kV sheath gas nitrogen 0.9L/min capillary voltage 35 V capillary temperature 200 °C tube lens offset voltage 15 V. (Reprinted from Pati et al., 2006, Simultaneous separation and identification of oligomeric procyanidins and anthocyanidins-derived pigments in raw red wine by HPLC-UV-ESI-MSn, Journal of Mass Spectrometry, 41, p. 869, with permission from John Wiley Sons, Ltd.)...

After treatment with the VP reagent, Lespedezae herba (5a. 6b) shows the phenolic compounds as red-brown zones (vis.). In addition to free catechin, epicatechin (R, -0,9), the dimeric procyanidins migrate into the upper R, range and trimeric procyanidins are found in the lower R, range. 

The red zones maybe due to dimeric and trimeric procyanidines, a biflavonoic catechiii-taxifolin, catechin and gallotannins. 

Trimeric procyanidins may also be divided into two categories ... 

HPLC analysis of the development of dimeric and trimeric procyanidins, as well as simple flavanols, extracted from the skins and seeds of red and white grapes, shows that concentrations decrease to a greater or lesser extent, but never increase (de Freitas, 1995). It has been observed that procyanidin B2 is the most common dimer in ripe Merlot and Cabernet Sauvignon (Table 6.11), followed by trimeric Ci. All the dimers are present in the seed extract, whereas procyanidins B4,... 

Bv and Bg are absent from the skins. Red and white grape seeds have similar distributions of procyanidins. On the other hand, dimer B2 is in the majority in red grape skins, but practically absent from white grapes, where it is replaced by Bi. These results show that dimeric and trimeric procyanidins, present in very low concentrations, are not the most important phenolic compounds in grapes. 

Utilization of procyanidin B-3 (32) as nucleophile in a coupling reaction with the 4-benzylsulfanylcatechin epimers (30) using AgBp4 in THF, gave the trimeric procyanidin (33) (26%) as the only isolable product (Scheme 4). 

Ricardo-Da-Silva JM, Rosec JP, Bourzeix M, Mourgues J, Moutounet M (1992) Dimer and trimer procyanidins in carignan and mourvedre grapes and red wines. Vitis 31 55-63... 

Moreover, monomers and dimers were shown to repress NO production, TNF alpha secretion, and NF-kB-dependent gene expression induced by interferon y, whereas the trimeric procyanidin C2 and Pycnogenol enhanced these parameters. In addition, in unstimulated RAW 264.7 macrophages, both procyanidin C2 and Pycnogenol increased TNF gamma secretion in a concentration and time-dependent manner. These results demonstrate that procyanidins act as modulators of the immune response in macrophages [105]. 

Jacques et al. (176) isolated two trimeric procyanidins that contained both (4yff 8)- and (4)ff- 8 2)ff- 0->7)-interflavanoid bonds, and partially defined their structures. Nonaka et al. (275) have now unequivocally established the locations of interflavanoid bonds in a series of these compounds from Cinnamomum zeylanicum (cinnamon), including a trimer, two tetramers (59), and a pentamer. The cinchonains such as 60 and 61, cinnamate derivatives of procyanidins are among the more unusual structural variations that have been found in the procyanidins (273). These compounds emphasize the high degree of nucleophilicity of the phloroglucinol ring in procyanidins. These no doubt are examples of a vari-... 

Procyanidins in vine shoots consist of partially galloylated units [80]. Thus, two trimeric procyanidins [Ci and epicatechin-(4(3 8)-epicatechin-(4(3- 8)-catechin], six dimeric procyanidins (Bi, B2, B3, B4, B7, and 3 -C>-galloyl-B2), in addition to 3-D-galloyl-(—)-epicatechin, (+)-catechin, and (—)-epicatechin, have been identified in acetone-water and ethyl acetate extracts from vine shoots [90]. 

Kashiwada, Y., Nonaka, G. andNishioka, I. (1986) Tannins and related compounds. XLVlll. Rhubarb. Isolation and characterization of new dimeric and trimeric procyanidins. Chem. Pharm. Bull. (Tokyo), 34,4083 91. 

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