UPLC-MS/MS-based molecular networking and NMR structural determination for the untargeted phytochemical characterization of the fruit of Crescentia cujete (Bignoniaceae)

The fruit pulp of Crescentia cujete is traditionally used in folk medicine for the treatment of a variety of respiratory conditions and gastrointestinal disorders. Due to the lack of a comprehensive phytochemical description of the fruit of this plant, its active compounds and rational quality control parameters have not yet been described. An untargeted metabolomics approach combining UPLC-MS/MS-based molecular networking with conventional isolation and NMR methods was carried out for the phytochemical profiling of the fruit pulp of Crescentia cujete. Sixty-six metabolites, including nine n-alkyl glycosides, twenty-three phenolic acid derivatives (such as cinnamoyl and benzoyl derivatives), fifteen flavonoids, four phenylethanoid derivatives and fifteen iridoid glycosides were identified at different levels of confirmation: eighteen confirmed structures (Level 1), six probable structures (Level 2) and forty two tentative candidates (Level 3). Among these, all four phenylethanoid derivatives were described for the first time within this species. In addition, 8-epi-eranthemoside, crescentiol A and crescentiol B were reported as three undescribed iridoid glucosides. The use of molecular networking has resulted in a detailed phytochemical overview of this species. This work provides a useful tool for further development and validation of appropriate analytical methods for routine quality control assessment of commercially available products containing the fruit of this species and further interpretation of their related pharmacological effects.

Keywords: Bignoniaceae; Calabash; Crescentia cujete; Flavonoids; Iridoids glycosides; Molecular networking; Phenolic acids; Phenylethanoids; Totumo; UPLC-MS/MS; n-alkyl glycosides.