Chemical Transformation of B- to A-type Proanthocyanidins and 3D Structural Implications.
J Nat Prod
; 87(5): 1416-1425, 2024 May 24.
Article
em En
| MEDLINE
| ID: mdl-38687902
ABSTRACT
In nature, proanthocyanidins (PACs) with A-type linkages are relatively rare, likely due to biosynthetic constraints in the formation of additional ether bonds to be introduced into the more common B-type precursors. However, A-type linkages confer greater structural rigidity on PACs than do B-type linkages. Prior investigations into the structure-activity relationships (SAR) describing how plant-derived PACs with B- and complex AB-type linkages affect their capacity for dentin biomodification indicate that a higher ratio of double linkages leads to a greater interaction with dentin type I collagen. Thus, A-type PACs emerge as particularly intriguing candidates for interventional functional biomaterials. This study employed a free-radical-mediated oxidation using DPPH to transform trimeric and tetrameric B-type PACs, 2 and 4, respectively, into their exclusively A-type linked analogues, 3 and 5, respectively. The structures and absolute configurations of the semisynthetic products, including the new all-A-type tetramer 5, were determined by comprehensive spectroscopic analysis. Additionally, molecular modeling investigated the conformational characteristics of all trimers and tetramers, 1-5. Our findings suggest that the specific interflavan linkages significantly impact the flexibility and low-energy conformations of the connected monomeric units, which conversely can affect the bioactive conformations relevant for dentin biomodification.
Texto completo:
1
Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Proantocianidinas
Idioma:
En
Revista:
J Nat Prod
Ano de publicação:
2024
Tipo de documento:
Article
País de publicação:
Estados Unidos