Molecular Modeling and Physicochemical Properties of Supramolecular Complexes of Limonene with α- and ß-Cyclodextrins.

This study evaluated three different methods for the formation of an inclusion complex between alpha- and beta-cyclodextrin (α- and ß-CD) and limonene (LIM) with the goal of improving the physicochemical properties of limonene. The study samples were prepared through physical mixing (PM), paste complexation (PC), and slurry complexation (SC) methods in the molar ratio of 1:1 (cyclodextrin:limonene). The complexes prepared were evaluated with thermogravimetry/derivate thermogravimetry, infrared spectroscopy, X-ray diffraction, complexation efficiency through gas chromatography/mass spectrometry analyses, molecular modeling, and nuclear magnetic resonance. The results showed that the physical mixing procedure did not produce complexation, but the paste and slurry methods produced inclusion complexes, which demonstrated interactions outside of the cavity of the CDs. However, the paste obtained with ß-cyclodextrin did not demonstrate complexation in the gas chromatographic technique because, after extraction, most of the limonene was either surface-adsorbed by ß-cyclodextrin or volatilized during the procedure. We conclude that paste complexation and slurry complexation are effective and economic methods to improve the physicochemical character of limonene and could have important applications in pharmacological activities in terms of an increase in solubility.

Hydrogenation of Halogenated 2'-Hydroxychalcones by Mycelia of Marine-Derived Fungus Penicillium raistrickii.

This study describes the chemoselective hydrogenation reaction of halogenated 2'-hydroxychalcones by the marine-derived fungus Penicillium raistrickii CBMAI 931. Initially, 2'-hydroxychalcone was utilized as a model for the selection of the appropriate conditions to perform the biotransformation reactions. The best results were obtained using mycelia and filtered culture broth, and this condition was chosen for the biotransformation reaction of 2'-hydroxychalcones substituted with methoxy and halogen groups. Experiments performed with 2'-hydroxychalcones dissolved in 600 µL-DMSO were more effective than those performed using 300 µL-DMSO, once solubility of the compounds influenced conversion rate in the liquid medium. The halogenated 2'-hydroxy-dihydrochalcones were obtained in good conversions (78-99%) and moderate isolated yields (31-65%). All biotransformation reactions using the marine-derived fungus P. raistrickii CBMAI 931 showed regioselective and chemoselective control for the formation of 2'-hydroxy-dihydrochalcones.