Evaluation of thymoquinone cancer chemo-preventive effect on oral leukoplakia: a randomized clinical trial

Abstract

Aim: This randomized clinical trial aimed to investigate the chemo-preventive role of thymoquinone in Nigella sativa extract in managing oral leukoplakia clinically, histologically, and at the molecular level. Methods: A total of 48 patients with oral leukoplakia were randomly allocated to three groups; Group A received local muco-adhesive tablets with Nigella sativa extract in 10 mg/kg dose, for three months, Group B same intervention but with Nigella sativa extract in 5 mg/kg dose, and lastly Group C was the placebo group. The outcomes assessed were clinical improvement, histologic improvement (degree of dysplasia), and molecular biomarkers Ki-67 and caspase-3 by immunohistochemistry. Results: There was a statistically significant decrease in lesion size in Groups A and B compared to the placebo group. At the molecular level, there was a statistically significant decrease in the expression of Ki-67 in both the Nigella sativa groups compared to the placebo group. While there was a statistically significant increase in caspase-3 in Group A only compared to the other groups. Conclusions: Thymoquinone in Nigella sativa extract is a promising chemo-preventive agent that can be used in the management of oral leukoplakia (the trial is registered on clinicaltrials.gov identifier: NCT03208790).