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

Osvaldo Valarini Junior,Everton Fernando Zanoelo,Lúcio Cardozo-Filho,Graciette Matiolli,Flávio Faria De Moraes,Carlos Eduardo Barão

doi:10.4025/actascitechnol.v41i1.39611

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.

Highlights

IntroductionThe arrangement of hydroxyl groups and hydrogen/oxygen atoms are responsible for the opposed affinities of external and internal surfaces of CDs with water and make them especially attractive as hosts of non-polar drugs, as the methyl jasmonate (MeJa). β-CD is cheap and commercially available with high purity, so it is usually preferred over the other CDs to form inclusion compounds with guest molecules for pharmaceutical purposes (Banchero, Ronchetti, & Manna, 2013)
The present study aimed to evaluate the formation of inclusion compounds of methyl jasmonate (MeJa) with HPβCD by applying supercritical CO2 (M4) in comparison with the typical complexation methods of kneading (M1), freeze drying (M2) and co-precipitation + freeze drying (M3)
The similarities between the FT-IR/attenuated total reflectance (ATR) spectra of free HPβCD and those of the formed inclusion compounds observed in Figure 1a. is another indication of complexation of MeJa with HPβCD by the four different methods of inclusion (Sambasevam, Mohamad, Sarih, & Ismail, 2013; Yuan, Lu, & Jin, 2014)

Summary

Introduction

The arrangement of hydroxyl groups and hydrogen/oxygen atoms are responsible for the opposed affinities of external and internal surfaces of CDs with water and make them especially attractive as hosts of non-polar drugs, as the MeJa. β-CD is cheap and commercially available with high purity, so it is usually preferred over the other CDs to form inclusion compounds with guest molecules for pharmaceutical purposes (Banchero, Ronchetti, & Manna, 2013). Since it has relatively poor water solubility, modified β-CDs have been more extensively used as hosts to enhance the stability, aqueous solubility and bioavailability of the free guest (Yao et al, 2014)

Methods

Results

Conclusion