Antioxidant and lipoxygenase inhibitory activities of pumpkin seed extracts

Pumpkin seeds have been implicated in providing health benefits. However their antioxidant or anti-inflammatory activity of their extracts has never been studied. Therefore, four commercially available pumpkin seeds were treated with two different extraction methodologies in order to obtain fractions with different content. The extracts were screened for their antioxidant activity using 2,2-diphenyl-1-picrylhydrazyl (DPPH) free radical scavenging assay and for their inhibitory activity against lipid peroxidation catalyzed by soybean lipoxygenase. Most extracts tested have demonstrated radical scavenging activity, which depends on their total phenolic content, with fractions rich in phenolics showing the strongest activity. On the other hand, the phenolic content of extracts does not determine their activity against lipoxygenase, as acetone and polar lipid fractions are its strongest inhibitors. The presence of molecules being able to scavenge radicals and inhibit lipoxygenase in pumpkin seeds may in part explain the health benefits attributed to them.