Substitution at the C-3 Position of Catechins Has an Influence on the Binding Affinities against Serum Albumin.

It is known that catechins interact with the tryptophan (Trp) residue at the drug-binding site of serum albumin. In this study, we used catechin derivatives to investigate which position of the catechin structure strongly influences the binding affinity against bovine serum albumin (BSA) and human serum albumin (HSA). A docking simulation showed that (-)-epigallocatechin gallate (EGCg) interacted with both Trp residues of BSA (one at drug-binding site I and the other on the molecular surface), mainly by π-π stacking. Fluorescence analysis showed that EGCg and substituted EGCg caused a red shift of the peak wavelength of Trp similarly to warfarin (a drug-binding site I-specific compound), while 3-O-acyl-catechins caused a blue shift. To evaluate the binding affinities, the quenching constants were determined by the Stern-Volmer equation. A gallate ester at the C-3 position increased the quenching constants of the catechins. Against BSA, acyl substitution increased the quenching constant proportionally to the carbon chain lengths of the acyl group, whereas methyl substitution decreased the quenching constant. Against HSA, neither acyl nor methyl substitution affected the quenching constant. In conclusion, substitution at the C-3 position of catechins has an important influence on the binding affinity against serum albumin.

Cervical varix accompanied by placenta previa in twin pregnancy.

BACKGROUND: Uterine cervical varix is a rare complication in pregnant women and can be the cause of obstetric hemorrhage in the vagina resulting in adverse events for both the mother and fetus. CASE: A 34-year-old Japanese woman was hospitalized at 18 weeks gestation because of cervical varix and placenta previa. Prophylactic tocolysis successfully controlled the obstetric hemorrhage. At 27 weeks gestation, emergent cesarean section was performed because of intractable hemorrhage from the marginal placenta previa. Intraabdominal findings revealed no vascular malformation of the uterus, and the operation was performed uneventfully. A speculum examination of the vagina and cervix at 1 month postpartum were unremarkable. CONCLUSION: It is important to recognize the clinical features and available treatments for cervical varix.