RESUMEN
Accurate potential energy curves (PECs) are obtained for 20 lowest lying electronic states of the NaLi molecule. The computational scheme used here is based on the multireference coupled cluster theory formulated in the (2,0) sector of the Fock space. The latter sector provides the description of states obtained by attachment of two electrons to the reference system. This makes it possible to adopt the doubly ionized NaLi+2 molecule as a Fermi vacuum. The latter has a very concrete advantage in calculations of the PECs since it dissociates into closed shell fragments (NaLi+2 â Na+ + Li+); hence, the restricted Hartree-Fock method can be used within the whole range of interatomic distances. Computed PECs and spectroscopic constants stay very close to the experimental values (if the latter are available) with the accuracy exceeding the other theoretical approaches including those based on the effective core polarization potentials. Relativistic corrections included at the infinite-order two-component level have a non-negligible effect on the accuracy of computed excitation and dissociation energies with contributions up to 50 cm-1.
RESUMEN
BACKGROUND: Isoflavonoids seem to possess positive cardiovascular and other beneficial effects in humans. HYPOTHESIS: Their low bioavailability, however, indicates that small isoflavonoid metabolites formed by human microflora can significantly contribute to these activities. STUDY DESIGN: Testing antiplatelet activity ex vivo in human blood and interaction with transition metals in vitro. METHODS: The effect on platelet aggregation induced by different triggers (arachidonic acid, collagen, ADP, TRAP-6), and interactions with transition metals (iron and copper chelation/reduction) were evaluated against four isoflavonoid-specific metabolites: S-equol; O-desmethylangolensin; 2-(4-hydroxyphenyl) propionic acid (HPPA); and 4-ethylphenol. RESULTS: S-equol, 4-ethylphenol and O-desmethylangolensin blocked platelet aggregation induced by arachidonic acid and collagen. S-equol even matched the potency of acetylsalicylic acid in the case of collagen, which is the most physiological inducer of aggregation. Moreover, their effects in general seemed to be biologically relevant and attainable at achievable plasma concentrations, with the exception of HPPA which was ineffective. While only O-desmethylangolensin mildly chelated iron and copper, all four compounds markedly reduced cupric ions. Their direct free radical scavenging effects seem to have little clinical relevance. CONCLUSION: This study has shown that S-equol, O-desmethylangolensin and 4-ethylphenol, arising from isoflavonoid intake, can have biologically relevant effects on platelet aggregation.