Enhanced dereplication of fungal cultures via use of mass defect filtering

Effective and rapid dereplication is a hallmark of present-day drug discovery from natural sources. This project strove to both decrease the time and expand the structural diversity associated with dereplication methodologies. A 5 min liquid chromatographic run time employing heated electrospray ionization (HESI) was evaluated to determine whether it could be used as a faster alternative over the 10 min ESI method we reported previously. Results revealed that the 5 min method was as sensitive as the 10 min method and, obviously, was twice as fast. To facilitate dereplication, the retention times, UV absorption maxima, full-scan HRMS and MS/MS were cross-referenced with an in-house database of over 300 fungal secondary metabolites. However, this strategy was dependent upon the makeup of the screening in-house database. Thus, mass defect filtering (MDF) was explored as an additional targeted screening strategy to permit identification of structurally related components. The use of a dereplication platform incorporating the 5 min chromatographic method together with MDF facilitated rapid and effective identification of known compounds and detection of structurally related analogs in extracts of fungal cultures.