SALIVARY BIOMARKER PROFILING AND EVALUATION OF A GLYCYRRHIZA GLABRA EXTRACT IN ORAL POTENTIALLY MALIGNANT DISORDERS AND ORAL SQUAMOUS CELL CARCINOMA

Background: Oral potentially malignant disorders (OPMD) can serve as precursors to the development of oral squamous cell carcinoma (OSCC), which shows the need for new non-invasive markers ideal for other treatment options. The present study assessed salivary profiles of oxidative stress, inflammatory condition, and miRNAs among healthy controls, with OPMD and OSCC individuals, along with studying the effects of extract from medicinal plants on apoptosis and cytotoxicity in OSCC.
Methods: Saliva samples without stimulation were gathered from healthy people, OPMD patients, and OSCC patients. Salivary IL-6 and IL-8 concentrations, malondialdehyde (MDA), and reduced glutathione (GSH) were measured, and miR-21 and miR-31 expression quantification was performed using qRT-PCR. The cytotoxic activity of the ethanolic Glycyrrhiza glabra extract was performed by using the MTT method, and apoptosis was measured through Annexin V/PI flow cytometry. Correlation and receiver operating characteristic (ROC) testing were performed to understand biomarker interactions.
Results: Salivary levels of IL-6, IL-8, and MDA showed an upward trend from the control group to OPMD and OSCC, while levels of GSH were reduced. Additionally, the levels of miR-21 and miR-31 also followed a similar trend. According to the biological activity of the plant, it was found to be toxic toward the OSCC cell line in a dose-dependent way. The calculated IC₅₀ value was 210.6 ± 18.7 µg/mL. The analysis of Annexin V/PI showed not only the decrease in the number of viable cells after treatment but also the increase in early and late apoptosis effects. Strong correlation was detected for a number of inflammatory, oxidative, and miRNA parameters. The results of ROC analysis showed that AUC values ranged from 0.86 to 0.94, with miR-21 presenting the best result of 0.94.
Conclusion: The observed changes in salivary inflammatory, oxidative stress, and miRNA profiles indicate that they can be useful for distinguishing healthy, OPMD, and OSCC groups. Moreover, the Glycyrrhiza glabra extract showed cytotoxicity and effect on apoptosis in OSCC cells allowing new therapies in anticancer.