Quantification and characterization of bioactive compounds isolated from pawpaw fruit (Asimina triloba)

Pawpaw (Asimina triloba) is a North American Annonaceae tree. Pawpaw is an important Native American food and medicine. Inflammation, wounds, gastrointestinal issues, and respiratory disorders have been treated with various parts of the plant. Despite its use, limited research on A. triloba's chemical composition and biological activity related to its traditional use is available. In chapter two, we conducted metabolomic studies based on untargeted analysis to identify possible bioactive compounds found in pawpaw fruit. Ultra-High Performance Liquid Chromatography (UHPLC) system coupled to a maXis impact quadrupole-time- of-flight high-resolution mass spectrometer (Q-TOF) (Bruker Co., Billerica, MA, United States) was used to analyze the pawpaw extracts. The raw data collected from the UPLC- HRMS was analyzed by utilizing the global metabolomic XCMS database. The MS information generated from UPLC-HRMS was uploaded to XCMS platform and analyzed using pairwise job mode to identify the relative abundance of the compound in different cultivars. In chapter three, the compounds identified through untargeted analysis were quantified using liquid chromatography-tandem mass spectrometry (LC-MS/MS). The LC-MS/MS analyses were performed using an HPLC system (Water Alliance 2695, Water Co., Milford, MA, United States) coupled with a Waters Acquity TQ triple quadrupole mass spectrometer operated in negative and positive electrospray ionization modes. In chapter four, the putatively identified compounds were assessed for their total antioxidant capacity using the CUPRAC assay. The influence of the compounds on the Nrf2/ARE pathway was determined through the Antioxidant Response Element (ARE) activation assay. The cytotoxicity of the compounds was evaluated against leukemia (HL- 60), melanoma (SKMEL5), breast cancer (MCF-7), ovarian cancer (SKOV3), and prostate cancer (PC3) cell lines. The antibacterial activity of the compounds was tested against Pseudomonas aeruginosa, Staphylococcus aureus, Mycobacterium smegmatis, and Escherichia coli.