Abstract
Metal-binding sites in epigallocatechin gallate (egcg) were identified by measuring 1H nuclear spin relaxation time T 1 under the coexistence of paramagnetic Mn 2+. The T 1 of the proton of gallate ring (D-ring) was shortened by the paramagnetic ion to a greater extent than the proton in gallocatechin ring (B-ring); the D-ring OH groups occupy the first coordination sphere around a metal ion to form a diolate chelate ring, while B-ring OH groups have a weak interaction with the metal ion. Comparison of changes in T 1 of egcg and epigallocatechin (egc) indicates that the gallate ring has a higher coordination capability than that of the gallocatechin ring so that the former plays a predominant role in the complex formation of egcg.
Original language | English |
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Pages (from-to) | 584-588 |
Number of pages | 5 |
Journal | Journal of Inorganic Biochemistry |
Volume | 99 |
Issue number | 2 |
DOIs | |
State | Published - Feb 2005 |
Keywords
- Catechins
- Mn complexes
- NMR
- Nuclear spin relaxation
- Polyphenols