Comparative evaluation of anticancer potential of Spilanthes paniculata leaf and flower essential oil using annexin V and orosphere formation in oral cancer cell line

Abstract

Spilanthes paniculata, a member of the Asteraceae family, is predominantly used as a traditional remedy in addressing oral ailments, particularly gum infections and sore throat. The flowers are chewed to alleviate toothache immediately. This study evaluated a comparison between the essential oils of leaf and flower derived from Spilanthes paniculata targeting the SCC9 oral cell lines using in vitro and in silico approaches. The anticancer activity was performed through an MTT assay, apoptosis assays using annexin V and orospheres formation assays. Molecular docking was performed between five selected phytocompounds against the p53 protein by using AutoDock 4.2.6 software. The results confirmed that the flower essential oil significantly reduced the cell viability in a dose-dependent manner, with an IC₅₀ value of 113.95 µg/mL. The apoptosis assays showed that the flower essential oil was approximately 2.5 times more effective in inducing early apoptosis at 50 µg/mL compared to the essential oil of the leaf. The orosphere formation assays further confirmed the anticancer potential of the flower essential oil. Spathulenol exhibited strong hydrogen bonding with the p53 protein. The ADMET prediction tools were used to predict the in silico pharmacokinetics and drug-like properties of the phytoconstituents. The results suggested that Spathulenol and Nerolidol have high gastrointestinal absorption (GIA), with estimated solubility (ESOL) values of - 3.17 and - 3.22, respectively, falling within the optimal range. These findings suggest that the flower's essential oil efficiently prevented the proliferation of oral cancer and observed a notable degree of cell death, inducing apoptosis and suggesting its significant antiproliferative activity against cancerous cell line which could be explored further for therapeutic applications.

Keywords: Spilanthes paniculata; ADMET; Apoptosis; Cytotoxicity; Molecular docking; Orospheres.