Cyclodextrins nanocavities effects on basic and acid fluorescence quenching of hydroxy-indoles

A. GUILLERMO BRACAMONTE; ALICIA V. VEGLIA*

JOURNAL OF PHOTOCHEMISTRY AND PHOTOBIOLOGY A-CHEMISTRY

ELSEVIER SCIENCE SA

Lugar: Amsterdam; Año: 2013 vol. 261 p. 20 - 20

1010-6030

he cyclodextrins effects on the serotonin (5HT) and 5-hydroxy-3-indolyl acetic acid (5HIA) fluorescence emission in acid and alkaline quenching conditions were analyzed. From Stern?Volmer plots, the quenching constants (KQ) were determined in the presence and absence of -cyclodextrin (CD) and hydroxypropyl--cyclodextrin (HPCD). In both media a decrease in the values of KQ was observed in the presence of CDs, as compared with their absence. In acid media, the decrease was: 36?39% with CD and 48?54% with HPCD for 5HIA and 5HT, respectively. In basic media, with the neutral receptors, these values are 69?29% with CD and 56?43% with HPCD for 5HIA and 5HT, respectively. Moreover, a complete quenching inhibition produced by ionized cyclodextrins was determined for both substrates. The results showed a net protective effect due to the guest inclusion into the cyclodextrin nanocavity. This study is particularly important for analytical determinations in such media.