Allspice ( Pimenta dioica ) essential oil mediates sphingosine kinase inhibition and subsequent induction of apoptosis in gastric cancer cells

Gastric cancer (GC), with its high morbidity and mortality rates, emerged as an important health concern in developing countries. Intracellular lipid kinases such as sphingosine kinase (SphK) play a pivotal role in the onset and progression of gastric cancers. Plant products such as essential oils are important drug candidates against various cancers. The Allspice (Pimenta dioica) essential oil was extracted by hydro-distillation methods. The anticancer activity was estimated against gastric cancer cells using MTT assay. The expression of SphK1 and SphK2 genes were assessed using qPCR. The Allspice essential oil (AEO) was shown to inhibit the proliferation of gastric cancer cells. Further, the level of reduced glutathione was significantly reduced by the AEO treatment with a concomitant increase in the reactive oxygen species levels. Further, the mRNA expression of SphK1 and SphK2 isoforms was evaluated; the pre-treatment of gastric cancer cells with varying doses of AEO significantly inhibited the expression of both SphK1 and SphK2. Besides, the expression of pro-apoptotic genes including caspases and apaf were upregulated in these cells treated with AEO. Overall, the study indicated the possible application of AEO in GC prevention by interfering with the SphK signaling and thereby inducing apoptotic cell death.