Background: Nowadays, the encapsulation of cytotoxic chemotherapeutic agents is attracting interest as amethod for drug delivery. We hypothesized that the efficiency of helenalin might be maximized by encapsulationin β-cyclodextrin nanoparticles. Helenalin, with a hydrophobic structure obtained from flowers of Arnicachamissonis and Arnica Montana, has anti-cancer and anti-inflammatory activity but low water solubility andbioavailability. β-Cyclodextrin (β-CD) is a cyclic oligosaccharide comprising seven D-glucopyranoside units,linked through 1,4-glycosidic bonds. Materials and
Methods: To test our hypothesis, we prepared β-cyclodextrinhelenalincomplexes to determine their inhibitory effects on telomerase gene expression by real-time polymerasechain reaction (q-PCR) and cytotoxic effects by colorimetric cell viability (MTT) assay.
Results: MTT assayshowed that not only β-cyclodextrin has no cytotoxic effect on its own but also it demonstrated that β-cyclodextrinhelenalincomplexes inhibited the growth of the T47D breast cancer cell line in a time and dose-dependent manner.Our q-PCR results showed that the expression of telomerase gene was effectively reduced as the concentrationof β-cyclodextrin-helenalin complexes increased.
Conclusions: β-Cyclodextrin-helenalin complexes exertedcytotoxic effects on T47D cells through down-regulation of telomerase expression and by enhancing Helenalinuptake by cells. Therefore, β-cyclodextrin could be superior carrier for this kind of hydrophobic agent.