Pumpkin Seed Oil as a Candidate Intranasal Delivery Medium: Evidence From Nasal Epithelial Cell Culture.

[OBJECTIVES] This study's overarching goal is to determine whether Cucurbita pepo seed oil (pumpkin seed oil, PSO) is suitable for intranasal delivery as a transfer medium, based on its physicochemical profile and biocompatibility with human nasal epithelial cell cultures. Research into PSO's safety and effects on the epithelium might lead to the development of new intranasal medicinal delivery methods based on natural lipids.

[METHODS] Septorhinoplasty often involves obtaining samples of nasal epithelium from healthy tissue. To ensure the highest level of sterility and eliminate potential microbial contamination, freshly harvested nasal tissue was immersed in phosphate-buffered saline (PBS) containing a 2% (v/v) antibiotic-antimycotic solution for 3 washes. After the attachment phase, cells were incubated continuously for 24 hours with C. pepo seed oil at concentrations of 1, 5, 15, 25, 50, 75, and 100 µL per well. The MTT colorimetric assay was used to quantify cellular metabolic activity, which was then used to determine cell viability.

[RESULTS] A half-maximal inhibitory concentration (IC50) of 62.75 µL, corresponding to a logIC50 of 1.798, was identified by dose-response modeling as an inhibitory trend. Regression analysis showed a strong correlation between oil exposure and decreased metabolic activity (R2=0.8978). Cell viability evaluations indicated that, when cells were exposed to C. pepo seed oil, metabolic performance changed gradually across the examined dose range. The reference condition, consisting of untreated cells, was used to normalize viability values. Cells showed a gradual slowing of metabolic activity with increasing oil volume, rather than a sudden cytotoxic response. Compared with the negative control group, statistical analysis showed that cell viability was significantly reduced by all tested doses of C. pepo seed oil. Rather than a rapid cytotoxic threshold, the magnitude of the viability loss increased steadily with increasing oil volume, suggesting a cumulative inhibitory effect.

[CONCLUSION] Cautionary formulation and dosing procedures are crucial because of the substantial decrease in survivability at higher doses. Additional research, including in vivo models and clinical assessments, is necessary to determine safe exposure limits, delivery modalities, and therapeutic effectiveness. However, in vitro evidence supports potential low-concentration ENT applications. In general, rhinoplasty and septoplasty procedures, among others in otolaryngology, show potential for the use of C. pepo seed oil as a locally applied, biologically active substance. PSO may be suitable for intranasal delivery as a transfer medium, based on its dose-dependent biocompatibility with human nasal epithelial cells. It should be investigated in future experimental studies.