Thermal and oxidative stability of the Ocimum basilicum L. essential oil/β-cyclodextrin supramolecular system

Abstract

Summary Ocimum basilicum L. essential oil and its β-cyclodextrin (β-CD) complex have been investigated with respect to their stability against the degradative action of air/oxygen and temperature. This supramolecular system was obtained by a crystallization method in order to achieve the equilibrium of complexed–uncomplexed volatile compounds in an ethanol/water solution at 50 °C. Both the raw essential oil and its β-CD complex have been subjected to thermal and oxidative degradation conditions in order to evaluate the protective capacity of β-CD. The relative concentration of the O. basilicum L. essential oil compounds, as determined by GC–MS, varies accordingly with their sensitivity to the thermal and/or oxidative degradation conditions imposed. Furthermore, the relative concentration of the volatile O. basilicum L. compounds found in the β-CD complex is quite different in comparison with the raw material. An increase of the relative concentration of linalool oxide from 0.3% to 1.1%, in addition to many sesquiterpene oxides, has been observed. β-CD complexation of the O. basilicum essential oil modifies the relative concentration of the encapsulated volatile compounds. Thus, linalool was better encapsulated in β-CD, while methylchavicol (estragole) was encapsulated in β-CD at a concentration close to that of the raw essential oil. Higher relative concentrations from the degradation of the oxygenated compounds such as linalool oxide and aromadendren oxide were determined in the raw O. basilicum L. essential oil in comparison with the corresponding β-CD complex. For the first time, the protective capability of natural β-CD for labile basil essential oil compounds has been demonstrated.

Aromatic Profiles of Essential Oils from Five Commonly Used Thai Basils

“…Siddique et al [ 27 ] suggested that the chemical compositions of essential oil depend largely on its colour. Moreover, the alteration of the essential oil colour as a result of their compositions is suggested to be due to thermal degradation, oxidation, isomerisation, dehydrogenation and polymerisation [ 17 , 27 , 28 , 29 ].…”

Nanoencapsulation of Plant Volatile Organic Compounds to Improve Their Biological Activities

“…Analysis of the thermal stability of laurel, oregano, and rosemary VOCs showed that all terpenes indicated a likelihood of thermo-degradation and monocarbonyl compounds, and hexanal, 2-hepaenal, and 2,4decadienal appeared as a result of autoxidation [95]. Hădărugă et al also reported that terpenes, including sesquiterpenes, had a greater susceptibility to degradation than the corresponding alcohols, and as such epoxidated sesquiterpenes and monoterpenes were found to be abundant after high temperature treatment [96]. The degradation of VOCs can result in a reduction in their bioactivities, for example, their antioxidant capacity.…”

Captisol®: an efficient carrier and solubilizing agent for essential oils and their components

“…CDs might enhance the solubility of EOs and their components thus higher concentrations could be used, produce easy measurable dosage forms, facilitate their dispersion and protect them from interactions with other excipients . CDs could also retain and allow a controlled release for EOs, offer them thermal, oxidative, light and chemical stability and increase their oral bioavailability . To the best of our knowledge no previous study attempted to investigate the inclusion complexes of Captisol® (sulfobutylether‐β‐cyclodextrin, SBE‐β‐CD) and Captisol‐G® (sulfobutylether‐γ‐cyclodextrin, SBE‐γ‐CD) with EOs and their components while, compared to native CDs, these CDs exhibit greater water solubility and a more desirable safety profile …”

“…with other excipients. 10 CDs could also retain and allow a controlled release for EOs, 11,12 offer them thermal, oxidative, light and chemical stability [13][14][15][16][17] and increase their oral bioavailability. 18 To the best of our knowledge no previous study attempted to investigate the inclusion complexes of Captisol® (sulfobutylether-β-cyclodextrin, SBE-β-CD) and Captisol-G® (sulfobutylether-γ-cyclodextrin, SBE-γ-CD) with EOs and their components while, compared to native CDs, these CDs exhibit greater water solubility and a more desirable safety profile.…”