Citronellal suppress the activity of ornithine decarboxylase in hypopharyngeal carcinoma cells

Citronellal, an acyclic monoterpene with an aldehyde group, is present in many plants, including species of Eucalyptus, Corymbia, Cymbopogon, Coriandrum. It is also known as rhodinol and possesses strong insect repellant and antifungal properties. In this study, we investigated the antiproliferative action of citronellal on hypopharyngeal carcinoma (FaDu) and normal (HEK-293) cell lines. Citronellal suppresses the activity of ornithine decarboxylase (ODC: 77.12±10.73 µM) and inhibits the proliferation of FaDu cells with an IC50 of 71.81±3.37 µM. The qRT-expression analysis depicts citronellal down-regulate the expression of ODC, and a robust binding interaction of citronellal with ODC was observed in molecular docking studies. Further, it also arrests the G2/M phase of FaDu cells, followed by an increase in the number of sub-diploid cells but was non-toxic to normal cell line. The toxicity prediction studies revealed citronellal follows the Lipinski rule of 5 and the Ghose rule. These observations provide experimental evidence for citronellal to be used as a new prototype for designing ODC inhibitors.