Supramolecular assemblies of carotenoids

Abstract

Carotenoid self-assemblies were formed by aqueous dilution of ethanolic solutions. The four 3′,6″-epimers of capsanthol ((all- E,3R, 5′R)-3,3′,6′-trihydroxy-β,κ-carotene) give rise to right- and left-handed card-pack and head-to-tail types of self-assemblies detected by exciton couplets appearing in the CD spectra. Slow kinetics of formation followed for some of the aggregates indicate the complexity of the process. The exciton signals do not appear from equimolar mixtures of related compounds that produce identical type of aggregates of opposite sense on their own. Transformation of self-assembly may reflect the population of κ-ring rotamers. © 2001. Wiley-Liss, Inc.