Abstract:Synthesis of arrecatannin A1(1) was accomplished from dimeric epicatechin electrophile, which was prepared by Zn(OTf) 2 mediated self-condensation, and monomeric catechin nucleophile. The condensation was successfully worked using Yb(OTf) 3 as a Lewis acid in good yield.
“…The optical rotation value, 1 H and 13 C NMR spectral data and mass spectrum data of synthetic 5 were in good accordance with the reported values 12 . As for arecatannin A3 ( 6 , ATA3), we have investigated Zn and Yb Lewis acids for equimolar condensation between an epicatechin-epicatechin-catechin nucleophile 22 , which was synthesized previously 21 , with the dimeric epicatechin electrophile 9 . Among the Lewis acids tested, it was found that 5.0 eq.…”
Section: Resultsmentioning
confidence: 99%
“…Thus, tetramer and pentamer species were tested for anti-cancer activity. The synthesis of compounds 1 – 6 allowed us to obtain sufficient quantities of purified compounds to screen against PC-3 prostate cancer cell lines together with arecatannin A1 (ATA1) 21 and cinnamtannin A2 (Epi-4) 23 , which were prepared previously (Fig. 5 ).…”
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.
“…The optical rotation value, 1 H and 13 C NMR spectral data and mass spectrum data of synthetic 5 were in good accordance with the reported values 12 . As for arecatannin A3 ( 6 , ATA3), we have investigated Zn and Yb Lewis acids for equimolar condensation between an epicatechin-epicatechin-catechin nucleophile 22 , which was synthesized previously 21 , with the dimeric epicatechin electrophile 9 . Among the Lewis acids tested, it was found that 5.0 eq.…”
Section: Resultsmentioning
confidence: 99%
“…Thus, tetramer and pentamer species were tested for anti-cancer activity. The synthesis of compounds 1 – 6 allowed us to obtain sufficient quantities of purified compounds to screen against PC-3 prostate cancer cell lines together with arecatannin A1 (ATA1) 21 and cinnamtannin A2 (Epi-4) 23 , which were prepared previously (Fig. 5 ).…”
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.
“…We identified catechin glucopyranoside, (epi)catechin dimer, procyanidin B4, arecatannin A1, arecatannin A2, (epi)catechin nonamer, piceid, and dehydroquercetin rhamnoside. These compounds were identified using ESI-TOFMS, NMR, and by comparison with spectra of known compounds or synthesized procyanidin B2, B4 [15], arecatannin A1, and arecatannin A2 [11,16]. This fraction did not show significant cytotoxic activity or suppression of the expression of FABP5 .Fig.…”
The aim of the present study was to characterize and evaluate the anti-cancer activity of proanthocyanidin-enriched fractions from adzuki beans. For this purpose, we concentrated proanthocyanidins from adzuki beans (Vigna angularis) into five fractions using Amberlite XAD-1180N, Toyopearl HW40F, and Sepacore C-18 reverse-phase flash column chromatography. Proanthocyanidin-enriched fractions were characterized as (epi)catechin hexamer, heptamer, and octamer, epigallocatechin-(epi)catechin pentamer, and epigallocatechin-(epi)catechin hexamer using electrospray ionization time-of-flight mass spectrometry and thiolytic degradation. These fractions showed significant anti-cancer activity against the human PC-3 prostate cancer cell line. They also significantly suppressed the expression of the fatty acid-binding protein 5 gene, which plays critical roles in cell growth and metastasis in prostate cancer.
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