Structure–Activity Relationship of Oligomeric Flavan-3-ols: Importance of the Upper-Unit B-ring Hydroxyl Groups in the Dimeric Structure for Strong Activities

Molecules

Yoshitomo Hamada⁴  Syota Takano²  Yoshihiro Ayano⁴  Masahiro Tokunaga²  Takahiro Koashi⁴  Syuhei Okamoto⁴  Syoma Doi⁴  Masahiko Ishida²  Takashi Kawasaki³  Masahiro Hamada¹  Noriyuki Nakajima¹  Akiko Saito⁴ 

[1] Biotechnology Research Center and Department of Biotechnology, Toyama Prefectural University, 5180, Kurokawa, Imizu, Toyama 939-0398, Japan; E-Mail:;Faculty of Engineering, Osaka Electro-Communication University (OECU), 18-8 Hatsu-cho, Neyagawa-shi, Osaka 572-8530, Japan; E-Mails:;Department of Pharmaceutical Sciences, Ritsumeikan University, 1-1-1 Nojihigashi, Kusatsu, Shiga 525-8577, Japan; E-Mail:;Graduate School of Engineering, Osaka Electro-Communication University (OECU), 18-8 Hatsu-cho, Neyagawa-shi, Osaka 572-8530, Japan; E-Mails:

关键词: condensed tannins;    oligomeric flavonoid;    synthesis;    DPPH radical scavenging activity;    antimicrobial activity;    cancer cell proliferation inhibitory activity;   

DOI  :  10.3390/molecules201018870

来源: mdpi

【 摘 要 】

Proanthocyanidins, which are composed of oligomeric flavan-3-ol units, are contained in various foodstuffs (e.g., fruits, vegetables, and drinks) and are strongly biologically active compounds. We investigated which element of the proanthocyanidin structure is primarily responsible for this functionality. In this study, we elucidate the importance of the upper-unit of 4–8 condensed dimeric flavan-3-ols for antimicrobial activity against Saccharomyces cerevisiae (S. cerevisiae) and cervical epithelioid carcinoma cell line HeLa S3 proliferation inhibitory activity. To clarify the important constituent unit of proanthocyanidin, we synthesized four dimeric compounds, (−)-epigallocatechin-[4,8]-(+)-catechin, (−)-epigallocatechin-[4,8]-(−)-epigallocatechin, (−)-epigallocatechin-[4,8]-(−)-epigallocatechin-3-O-gallate, and (+)-catechin-[4,8]-(−)-epigallocatechin and performed structure–activity relationship (SAR) studies. In addition to antimicrobial activity against S. cerevisiae and proliferation inhibitory activity on HeLa S3 cells, the correlation of 2,2-diphenyl-l-picrylhydrazyl radical scavenging activity with the number of phenolic hydroxyl groups was low. On the basis of the results of our SAR studies, we concluded that B-ring hydroxyl groups of the upper-unit of the dimer are crucially important for strong and effective activity.

【 授权许可】

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