Molecules. 2019 Oct 11;24(20). pii: E3667. doi: 10.3390/molecules24203667.

Elucidation of the Interaction between Flavan-3-ols and Bovine Serum Albumin and Its Effect on Their In-Vitro Cytotoxicity.

Fujii Y¹, Suhara Y², Sukikara Y³, Teshima T⁴, Hirota Y⁵, Yoshimura K⁶, Osakabe N⁷.

Author information

1: Department of Bio-Science and Engineering, Shibaura Institute of Technology, 307 Fukasaku, Munumaku, Saitama 337-8570, Japan. mf17059@shibaura-it.ac.jp.
2: Department of Bio-Science and Engineering, Shibaura Institute of Technology, 307 Fukasaku, Munumaku, Saitama 337-8570, Japan. suhara@sic.shibaura-it.ac.jp.
3: Department of Bio-Science and Engineering, Shibaura Institute of Technology, 307 Fukasaku, Munumaku, Saitama 337-8570, Japan. bn14036@shibaura-it.ac.jp.
4: Department of Bio-Science and Engineering, Shibaura Institute of Technology, 307 Fukasaku, Munumaku, Saitama 337-8570, Japan. BN15037@shibaura-it.ac.jp.
5: Department of Machinery and Control Systems, Shibaura Institute of Technology, 307 Fukasaku, Munumaku, Saitama 337-8570, Japan. hirotay@sic.shibaura-it.ac.jp.
6: Department of Machinery and Control Systems, Shibaura Institute of Technology, 307 Fukasaku, Munumaku, Saitama 337-8570, Japan. kenjiroy@sic.shibaura-it.ac.jp.
7: Department of Bio-Science and Engineering, Shibaura Institute of Technology, 307 Fukasaku, Munumaku, Saitama 337-8570, Japan. nao-osa@sic.shibaura-it.ac.jp.

Abstract

Flavan-3-ols (FLs), specifically catechin and its oligomer B-type procyanidins, are suggested to potently bind to bovine serum albumin (BSA). We examined the interaction between BSA and FLs by fluorescence quenching and found the following order of binding activities to BSA: cinnamtannin A2 (A2; tetramer) > procyanidin C1 (C1; trimer) ≈ procyanidin B2 (B2, dimer) > (-)epicatechin (EC, monomer). Docking simulations between BSA and each compound at the binding site showed that the calculated binding energies were consistent with the results of our experimental assay. FLs exerted cytotoxicity at 1000 μg/mL in F11 cell culture with fetal bovine serum containing BSA. In culture containing serum-free medium, FLs exhibited significant cell proliferation at 10^-4 μg/mL and cytotoxicity was observed at concentrations greater than 10 μg/mL. Results of this study suggest that interactions between polyphenols and BSA should be taken into account when evaluating procyanidin in an in vitro cell culture system.