Biological activity of pumpkin pulp extracts: cytoprotection, anti-inflammatory effects, and photoprotection in human skin cells

Pumpkin extracts are rich in vitamins and bioactive compounds, offering antioxidative, anti-inflammatory, and wound-healing properties, making them valuable in dermatology and cosmetics, however pumpkin pulp extracts have not been evaluated before for their cutaneous biological activities. This study evaluated the biological activity of methanolic pumpkin pulp extracts from six Serbian accessions of <i>Cucurbita (C.) maxima</i> and <i>C. moschata</i> on normal keratinocytes (HaCaT) and melanoma (FemX) cells. The extracts showed no cytotoxicity to normal cells up to 1000 μg/mL and exhibited concentration-dependent cytotoxicity to melanoma cells (determined by MTT assay). They also demonstrated antioxidative effects against H₂O₂-induced oxidative stress in H₂DCFDA assay, and reduced tumor necrosis factor -α/interferon-gamma-γ-induced expression of pro-inflammatory cytokine interleukine-1β in HaCaT cells, as shown in the cell-based ELISA assay. Sun protection factor (SPF) calculations for all six accessions confirmed the photoprotective potential of the extracts, with noticeable differences in SPF values between species and varieties. The highest SPF value was observed in the <i>C. moschata</i> variety. Significant variations in biological activities among the examined accessions were noted, with <i>C. maxima</i> extracts showing pronounced antioxidant and antiinflammatory properties while <i>C. moschata</i> extract showed the highest SPF values. These findings represent the first report on the skin-beneficial effects of pumpkin pulp extracts, identifying them as sustainable sources of safe, bioactive compounds with antioxidant, anti-inflammatory, and photoprotective properties for dermatological or cosmetic applications.