A practical chemometric approach using UPLC–QTOF/MS tool to investigate three varieties of pumpkin species and in vitro bioactivities

Abstract

The OPLS-DA, the UPLC–QTOF/MS and chemometric approaches were adopted to discriminate the different varieties belonging to three pumpkin species. Furthermore, this study included a comparison of the phenolic metabolites, antioxidant (DPPH, FRAP and ABTS activity), in vitro α-glucosidase and α-amylase activities, and cell cytotoxicity of the leaves of three varieties of pumpkin species (Cucurbita moschata, C. maxima, and C. pepo).Leaves of all three varieties of pumpkin species contained 23 phenolic metabolites. The OPLS-DA, the UPLC–QTOF/MS and chemometric approach showed that genistin was the candidate biomarker responsible for the separation of butternut squash (C. maxima) from the other two species, while 7-methylquercetin-3-galactoside-6″-rhamnoside-3‴-rhamnoside separated the Caserta squash (C. pepo) from the other two pumpkin species. Leaves of Green Hubbard (C. maxima) showed the highest antioxidant capacity (FRAP and ABTS activities), while butternut squash (C. moschata) showed the highest DPPH scavenging activity. Leaf extracts of butternut squash (C. moschata) and Green Hubbard (C. maxima) showed higher inhibition of α-glucosidase activity (IC50 18.22 μg mL−1) and α-amylase (IC50 18.11 μg mL−1) activities respectively, with no cytotoxic effect detected.The phenolic metabolites identified herein for the leaves of each variety of pumpkin species can be potential control markers for further standardisation. Leaves of Green Hubbard (C. maxima) provides functional properties for health benefits.