title: Chiral Recognition of Diketopiperazine Cyclo(Pro-Gly) and Propranolol Using (-)-Epigallocatechin-3-O-gallate.
abstract: In the (1)H-NMR spectrum of a solution containing an equimolecular amount of cyclo(L-Pro-Gly), cyclo(D-Pro-Gly) and (-)-epigallocatechin-3-O-gallate (EGCg) in a D2O, a difference in the chemical shift of (1)H-NMR signal for H7α, H7β,8α of the Pro residue was observed. Judging from the crystal structures of the 2 : 2 complexes of EGCg and cyclo(L-Pro-Gly), cyclo(D-Pro-Gly), the difference in the chemical shift resulted mainly from a magnetic anisotropic shielding effect by the ring current from the B ring of EGCg. Therefore, it was considered that chirality of cyclo(Pro-Gly) was recognized by EGCg in the D2O solution. Furthermore, in the (1)H-NMR spectrum of a solution containing an equimolecular amount of racemic propranolol ((R)- and (S)-propranolols) and EGCg in D2O, the (1)H-NMR signal for H2 of the naphthalene group was observed as two doublets, suggesting that the racemic propranolol formed diastereomers of complexes with EGCg; as a result, chirality of propranolol was recognized by EGCg in the D2O solution.
authors.affiliation: Faculty of Pharmacy and Pharmaceutical Sciences, Fukuyama University.
authors.forename: Takashi
authors.initials: T
authors.lastname: Ishizu
authors.forename: Hiroyuki
authors.initials: H
authors.lastname: Tsutsumi
authors.forename: Emi
authors.initials: E
authors.lastname: Yokoyama
authors.forename: Haruka
authors.initials: H
authors.lastname: Tanabe
authors.forename: Aoi
authors.initials: A
authors.lastname: Yokoyama
mesh_terms: D002392:Catechin / Q000031:analogs & derivatives* / Q000737:chemistry; D054659:Diketopiperazines / Q000032:analysis* / Q000737:chemistry*; D015394:Molecular Structure; D010456:Peptides, Cyclic / Q000032:analysis* / Q000737:chemistry*; D011433:Propranolol / Q000032:analysis* / Q000737:chemistry*; D066244:Proton Magnetic Resonance Spectroscopy / Q000592:standards; D012015:Reference Standards
chemical_list: D054659:Diketopiperazines; D010456:Peptides, Cyclic; D002392:Catechin; C062238:cyclo(prolylglycyl); D011433:Propranolol; C045651:epigallocatechin gallate