Effects of branched cyclodextrins on the solubility and stability of terpenes

Abstract

In order to investigate the application potential of branched CDs, the solubilizing ability and the stabilizing ability of G2-betaCD and GUG-betaCD were investigated by using twelve terpenes (d-limonene, myrcene, terpinolene, geraniol, l-menthol, nerol, alpha-terpineol, citral, d-citronellal, l-perillaldehyde, (R)-l-carvone, and menthone) as guest compounds. G2-betaCD and GUG-betaCD showed more solubilizing ability for these twelve terpenes than betaCD, and the ability of GUG-betaCD was almost the same as that of G2-betaCD. The stabilizing ability of terpene-GUG-betaCD complexes was different from that of G2-betaCD. GUG-betaCD was superior to G2-betaCD, especially in the solid state. This result may have been caused by the difference in structure of side chain, namely the hydroxymethyl group in G2-betaCD and the carboxyl group in GUG-betaCD.