Recent Syntheses of Proanthocyanidins

Makabe, Hidefumi

doi:10.3987/rev-13-782

Cited by 16 publications

(5 citation statements)

References 35 publications

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“…To obtain oligomeric procyanidins in a pure state for biological studies, a variety of pure and structurally determined synthetic standard compounds are required. Currently, synthetic efforts have been carried out to obtain pure procyanidin oligomers 8 – 11 . However, reports of the synthesis of catechin and/or epicatechin oligomers, especially those longer than tetramers are rather limited.…”

Section: Introductionmentioning

confidence: 99%

Epicatechin oligomers longer than trimers have anti-cancer activities, but not the catechin counterparts

Takanashi

Suda

Matsumoto

et al. 2017

Sci Rep

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Since procyanidins (oligomeric catechin or epicatechin) were reported to exhibit health benefits, much attention has been paid to the synthesis of these compounds, especially those that are longer than trimers. In the present study, syntheses of cinnamtannin A3 (epicatechin pentamer), A4 (epicatechin hexamer), catechin tetramer, pentamer, arecatannin A2 (epicatechin-epicatechin-epicatechin-catechin) and A3 (epicatechin-epicatechin-epicatechin-epicatechin-catechin) were achieved. The key reaction was a Lewis acid mediated equimolar condensation. The antitumor effects of these synthesized compounds against a human prostate cancer cell line (PC-3) were investigated. Among the tested compounds, cinnamtannin A3, A4 and arecatannin A3, which possess epicatechin oligomers longer than tetramers as the basic scaffold, showed significant activities for suppression of cell growth, invasion and FABP5 (fatty acid-binding protein 5) gene expression. Effects on cell cycle distribution showed that cell cycle arrest in the G2 phase was induced. Furthermore, these epicatechin oligomers suppressed significantly the expression of the cancer-promoting gene, FABP5, which is related to cell proliferation and metastasis in various cancer cells. Interestingly, the suppressive activities were associated with the degree of oligomerization of epicatechin. Thus, synthetic studies clearly demonstrate that epicatechin oligomers longer than trimers have significant anti-tumorigenic activities, but not the catechin counterparts.

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Section: Introductionmentioning

confidence: 99%

Epicatechin oligomers longer than trimers have anti-cancer activities, but not the catechin counterparts

Takanashi

Suda

Matsumoto

et al. 2017

Sci Rep

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“…A significant disadvantage of using chromatographic techniques in proanthocyanidin analysis is the lack of polymer reference standards in a high purity form. Progress has been made in the preparation of synthetic proanthocyanidins 27 , with Ohmori et al . 28 reporting the assembly of catechin monomers to yield a 24-mer.…”

Section: Overall Discussionmentioning

confidence: 99%

Characterisation of high molecular weight hop proanthocyanidins using Analytical Ultracentrifugation

Gadon

Linforth

Harding

et al. 2019

Sci Rep

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We report the novel application of Analytical Ultracentrifugation (AUCF) to characterise the polymeric proanthocyanidin fraction of hops. Extraction of hop samples with 70% acetone (aq) followed by a C-18 Solid Phase Extraction yielded polyphenolic fractions for AUCF analysis. Sedimentation velocity experiments demonstrated the presence of discrete molecular weight bands of proanthocyanidins, as opposed to a continuous distribution of molecular weights. There were 4 such bands for Saaz hop (0.15, 1.1, 2.7 and 4.4S) and 3 bands for Magnum (0.15, 1.6 and 3.0S). The method resulted in a reproducible size (sedimentation coefficient) distribution for replicate runs of the same extract and for extracts prepared from different samples of the same hop variety. Sedimentation equilibrium experiments were then used to fit molecular weight distributions using the new SEDFIT-MSTAR method for the same samples. Thus we report for the first time polymeric proanthocyanidins in hops with molecular weights of up to 100 kDa in Saaz hop (or up to 56 kDa in Magnum). This represents the first application of AUCF to characterise complex fractions of polyphenolics extracted from botanical sources and the methodology developed should find wider application in the study of this diverse and bioactive class of compounds.

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“…As a result, a number of synthetic approaches have been reported. Timely reviews by Makabe 1 and by Ferreira 2 and a book by Quideau 3 summarize previous work on type B procyanidins. Syntheses of type A procyanidins included an innovative microwave-mediated route to diinsininone by Selenski and Pettus in 2006, 4 an elegant synthesis of procyanidin A2 by Ito, Ohmori and Suzuki via an alkoxyketal derivative of epicatechin in 2014, 5 and the successful synthesis of proanthocyanidins A1 and A2 by Sharma and coworkers in 2015.…”

Section: Rapid Assembly Of the Procyanidin A Skeletonmentioning

confidence: 99%

Rapid assembly of the procyanidin A skeleton

Kraus

Geraskin

2017

Tetrahedron Letters

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Recent Syntheses of Proanthocyanidins

Abstract: -Recently proanthocyanidins have been paid much attention due to their significant biological activities and health benefitical effects. The author reviewed recent progress of the syntheses of proanthocyanidins including our work within this decade.

Cited by 16 publications

References 35 publications

Epicatechin oligomers longer than trimers have anti-cancer activities, but not the catechin counterparts

Epicatechin oligomers longer than trimers have anti-cancer activities, but not the catechin counterparts

Characterisation of high molecular weight hop proanthocyanidins using Analytical Ultracentrifugation

Rapid assembly of the procyanidin A skeleton

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