Preparation of celery essential oil-based nanoemulsion by ultrasonication and evaluation of its potential anticancer and antibacterial activity

Introduction: Plants have always been a significant source of natural active components with biological properties. Celery seed oil (extracted from Apium graveolens) has several potential applications, but its therapeutic uses in the form of nanoemulsion formulation need to be investigated further in order to meet the demand in cancer treatment, and to alleviate the prevailing crisis arising from increased antimicrobial resistance. Methods: The therapeutic potential of celery seed oil was investigated through the formulation and testing of a nanoemulsion developed with Tween 80 (a non-ionic surfactant) and the utilization of an ultrasonication technique. Anticancer and apoptotic properties of the formulation were evaluated through MTT and Annexin V-FITC assays. The clonogenic assay aided in the identification of the antiproliferative properties of the formulation on oral squamous cell carcinoma. The antimicrobial study was supported by agar well diffusion assay, membrane integrity test and scanning electron microscopy. Results: Experiments identified relevant parameters, including optimal surfactant concentration and emulsification time. GC-MS analysis identified various components in the celery oil, but not their biological activities. A sonication time of 20 min resulted in a droplet diameter of 23.4 ± 1.80 nm. The IC50 concentration of the optimal nanoemulsion formulation against SAS cells was 1.4 µL/mL. At this concentration, cell proliferation was significantly reduced through inhibition of the anchorage-independent cell growth by disrupting colony formation and inducing cell death (apoptosis) of cancer cells. The nanoemulsion was also treated with a microbial suspension of S. aureus, and displayed antibacterial properties through lipid membrane fusion, causing cytoplasmic leakage as verified through agar well diffusion and membrane permeability assays. Scanning electron microscopy revealed complete distortion of the bacterial pathogen. Conclusion: The results in this study present celery as a possible constituent for cancer therapeutics and as a candidate for aggressive, yet safe cancer treatment. The celery-based nanoemulsion has the potential to act as a key alternative to standard antibiotic therapy.