Antioxidant content of C. maxima and C. pepo seeds and the cytotoxic effect on chronic lymphocytic leukemia cell lines

Pumpkin seeds are essential for health due to their rich content, especially their oils, which are high in phenolic compounds. These compounds can be an alternative treatment for diabetes mellitus by reducing blood glucose levels. This study examined the seeds of C. maxima and C. pepo, which were grown in the Sakarya-Arifiye region and harvested in November 2022. DPPH (2,2-diphenyl-1-picrylhydrazyl) radical scavenging activity, total polyphenol, and flavonoid content of methanolic extracts were measured spectrophotometrically, with three separate extraction replicates for each sample. The total phenolic content was 0.31 ± 0.09 mg/g for C. pepo seeds and 0.19 ± 0.02 mg/g for C. maxima seeds. Total flavonoid content was 217.2 ± 20.9 μg/g in C. pepo and 162.9 ± 19.3 μg/g in C. maxima. Antioxidant activity levels demonstrated 12.7 ± 2.4% inhibition for C. pepo and 15.09 ± 0.4% for C. maxima in DPPH scavenging. In the MEC-1 (mutant p53 chronic B cell leukaemia) cell line, the IC50 value for C. pepo was 205 mg/ml, while for C. maxima, it indicated a proliferative effect. In the HG-3 (wild-type chronic B cell leukaemia) cell line, IC50 was 209 mg/ml for C. pepo and 940 mg/ml for C. maxima. These findings indicate that antioxidant, flavonoid, and phenolic content vary by species and growing conditions, influencing antiproliferative effects on cancer cells. Further studies on pumpkin seeds’ effects on metabolic pathways in various diseases will be beneficial.