Complexation and physicochemical analysis of hydrophobic molecules of methyl jasmonate with Hydroxypropyl-β–Cyclodextrin

Abstract

In the present study, methyl jasmonate (MeJa) was included in 2-hydroxypropyl-β-cyclodextrin (HPβCD) by grinding (M₁), freeze drying (M₂), co-precipitation + freeze drying (M₃) and by applying supercritical carbon dioxide (M₄). FT-IR/ATR, FT-Raman, TGA, and DSC analyses of the complexation products confirmed that MeJa/HPβCD complexes were formed by the four different examined methods of inclusion. FT-IR/ATR supported the inclusion, mainly based on the reduction of intensity of absorption at the wavelength of maximum absorbance of free MeJa (1733 cm^-1), which was 27.69 au before inclusion. From these results, M₃ (2.29 au) and M₄ (0.90 au) were the most efficient techniques for complexation. TGA, and DSC analyses pointed out that the complexes formed by the methods M₃ and M₄ had the least loss of mass below approximately 305°C (the temperature that free HPβCD starts to decompose thermally). Except for M₁, the results of antioxidant activity (AA) based on the DPPH assay revealed that the AA of the inclusion compounds were higher than that of free MeJa (α = 0.05). The best methods in terms of AA and thermal stability of the formed inclusion compounds were M₃ and M₄.