Inclusion studies of falcarinol in β-cyclodextrin

Falcarinol is a natural C17-polyacteylenic pesticide (phytoalexin) present in Apiaceae vegetables such as carrot (Daucus carota L.). Recently has attracted a lot of attention due to its interesting biological activities such as cytotoxic, antibacterial, antimycobacterial [1]. However, falcarinol suffers from photo- and thermal degradation, due to the presence of unstable triple bonds in its structure, which limits its possible applications. In the present work the thermal and photo-stability of falcarinol alone and in complex with β-cyclodextrin was studied. Falcarinol was isolated from the endemic Sardinian plant Seseli praecox (Gamisans) Gamisans (Apiaceae) [2]. Falcarinol/β-cyclodextrin complexes were prepared and the inclusion complex was initially characterised by NMR (ROESY) spectroscopy. Accelerated thermostabilty testing proved to be an extrememely agressive method for this type of constituent resulting in the complete degradation of both, the compound and its inclusion complex. On the other hand, photostability studies were carried out successfully as the β-cyclodextrin complex provided protection to the substance which kept its macroscopically properties and protected the substance from degradation. In comparison the photostability assay generated a loss of 15% in uncomplexed falcarinol. Therefore, inclusion in β-cyclodextrin was proved to be a good method for the photoprotection of falcarinol.

Figure 1: Falcarinol/ß-cyclodextrin inclusion complex

References: 1. Santos, PAG et al. (2005) Plant Science 168: 1089–1096.

2. Leonti M et al. (2010) Biochem Pharmacol 79: 1815–1826.