Therapeutic efficacy of quercetin versus its encapsulated nanoparticle on tongue squamous cell carcinoma cell line

Quercetin, a bioactive flavonoid, has well-documented antitumour properties; however, its clinical application is limited by its hydrophobicity, poor bioavailability, and stability. These limitations can be addressed via the use of nanotechnology-based drug delivery systems. In this study, we sought to develop polylactide-coglycolide nanoparticles functionalized with polyethylene glycol as the drug vehicle for encapsulating quercetin, and further investigated their anticancer potential against the human tongue squamous cell carcinoma cell line HNO-97 by comparing their effica-cy with that of free quercetin and doxorubicin as standard chemotherapeutic control. Quercetin NPs (QNPs) were synthesized and characterized for particle size, zeta potential, and entrapment efficiency via dynamic light scattering and for morphology via transmission electron microsco-py. The cytotoxicity was evaluated at two time intervals (4 and 24 hours) via the MTT assay. Apoptosis analysis was performed via flow cytometry, and the gene expression levels of Bax, Bcl-2, and PI3K were evaluated via RT-qPCR. After 24 hours of treatment, the in vitro cell cyto-toxicity study revealed that, compared with free quercetin (59.7 µM) and DOX (74.7 µM), QNPs exhibited superior cytotoxicity (IC₅₀ = 41.4 µM). The anticancer efficacy of the QNPs was fur-ther confirmed by enhanced cellular apoptosis. Moreover, treating cells with QNPs resulted in increase in the Bax expression level and the decrease in the Bcl-2 and PI3K expression levels, resulting in the highest Bax/Bcl-2 ratio (31.03). In conclusion, the overall study results suggest that quercetin encapsulated PLGA-PEG nanoparticles may serve as potential drug candidates for the treatment of human tongue squamous cell carcinoma.