In situ analysis of Asimina triloba (paw paw) plant tissues for acetogenins via the droplet-liquid microjunction-surface sampling probe coupled to UHPLC-PDA-HRMS/MS†
Asimina triloba, commonly known as paw paw, is one of approximately 2100 species in the Annonaceae family, scores of which are known to biosynthesize bioactive secondary metabolites, termed Annonaceous acetogenins. Even with over 400 acetogenins identified, a high-throughput screening protocol for these compounds does not exist. Advances in direct ambient ionization mass spectrometry have opened the door to many metabolite profiling methodologies, but for acetogenins, this is often complicated by the abundance of isomers that are present. A droplet-liquid microjunction-surface sampling probe coupled to UPLC-PDA-HRMS/MS system was employed to detect acetogenins in situ from A. triloba. The seeds, fruit pulp, twigs, leaves, and flowers of A. triloba were all examined for acetogenins. Additionally, lithium was infused post-column to increase the sensitivity of the fragments, thus allowing for characterization of the structural classes, and mass defect filtering was used to mine the data for the various acetogenin analogues. This surface sampling system allowed for the rapid identification and differentiation of Annonaceous acetogenins directly from the various organs of A. triloba, including the never before studied flowers.