Nutraceutical potential of Cucurbita maxima Duchesne pulp extract

Pumpkin pulp (Cucurbita maxima Duchesne) is recognized for its antioxidant properties, but its antimicrobial and antibiofilm activities remain insufficiently explored. This study comprehensively characterized the phytochemical profile of C. maxima pulp extract (CmPE) and assessed its potential as a natural antimicrobial agent. High-performance liquid chromatography-mass spectrometry analysis revealed a rich composition of bioactive compounds, including gallic acid, ellagic acid, naringin, morin, and kaempferol. CmPE demonstrated potent antioxidant activity, with IC₅₀ values of 16.6 and 28.5 μg·mL^-1 in 2,2-diphenyl-1-picrylhydrazyl (DPPH) and 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS^•+) assays, respectively. Antimicrobial testing established CmPE's broad-spectrum efficacy, with minimum inhibitory concentration (MIC) values ranging from 15 to 500 μg·mL^-1 against bacteria and yeasts. Furthermore, CmPE reduced biofilm viability by 30% in Staphylococcus saprophyticus and Cryptococcus gattii at MIC, coupled with evidence of microbial plasma membrane damage, as shown in mechanistic studies. These findings underline CmPE's unique combination of antioxidant, antimicrobial, and antibiofilm activities, offering promising nutraceutical applications to address the growing challenge of microbial resistance.