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

Authors :
Syuhei Okamoto
Masahiko Ishida
Akiko Saito
Takashi Kawasaki
Takahiro Koashi
Yoshitomo Hamada
Yoshihiro Ayano
Masahiro Hamada
Masahiro Tokunaga
Noriyuki Nakajima
Syoma Doi
Syota Takano
Source :
Molecules, Molecules, Vol 20, Iss 10, Pp 18870-18885 (2015), Volume 20, Issue 10, Pages 18870-18885
Publication Year :
2015
Publisher :
MDPI AG, 2015.

Abstract

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.

Details

ISSN :
14203049
Volume :
20
Database :
OpenAIRE
Journal :
Molecules
Accession number :
edsair.doi.dedup.....59dccf4b629c1ae29927e133a8cc7763