Chiral detection of carotenoid assemblies

TitleChiral detection of carotenoid assemblies
Publication TypeJournal Article
Year of Publication2001
AuthorsZsila, F, Bikádi, Z, Deli, J, Simonyi, M
Pagination446 - 453
Date Published2001
KeywordsCircular Dichroism, Exciton signals, J to H transformation, Mixed aggregates, Supramolecular chirality

Carotenoid assemblies were produced by aqueous dilution of ethanolic solutions. UV/VIS and CD spectroscopy revealed the formation of J- and H-types of aggregates of both right- and left-handed kinds. Simulation of UV/VIS spectra of the aggregates showed characteristic differences between the two types. 6′-Epimers of capsanthol ((all-E,3R,3′S,5′R)-β,κ-carotene- 3,3′,6′-triols) formed assemblies with increased chirality in dilute solution. While the absorption of 6′R-capsanthol giving H-type aggregate does not depend on the concentration, 6′S-capsanthol yielding J-type assembly showed concentration-dependent absorption intensity. Dilute aggregate of 6′R-capsanthol is characterized by an extremely large A value of -6,600. The transformation of J- to H-type assembly was observed in the mixtures of the epimers producing an intermediate kind of aggregate. A hypothetical structure for H-type assemblies is proposed. © 2001 Wiley-Liss, Inc.