High throughput screening of natural products utilizing pulsed ultrafiltration or magnetic microbead affinity selection with UHPLC-MS/MS

University of Illinois College of Pharmacy, 833 S Wood Street, Chicago, IL

As natural products remain an important resource in the discovery of new potential drugs, it is imperative to develop efficient and sensitive high-throughput screening techniques to find ligands for macromolecular receptors and enzymes. Two techniques developed by our research group, Pulsed Ultra Filtration (PUF) and the higher-throughput Magnetic Microbead Affinity Selection Screening (MMASS), are target-based screening techniques that can be used to identify potential ligands within complex mixtures such as natural product extracts. Based on PUF and MMASS screening of 14 traditional Native American medicinal botanicals for ligands to the anti-inflammation target 15-lipoxygenase (15-LOX), Proserpinaca palustris L – Mermaid Weed – showed a hit with an accurate mass of 449.108(+) and 447.095(-). However, this compound could be one of a variety of constitutional isomers of this mass known in this and related species. Given that these constitutional isomers showed similar retention times, MS/MS fragmentation patterns were used to distinguish them. UHPLC was used with a Shimadzu IT-TOF high resolution hybrid mass spectrometer and LCMS-8040 triple quadrupole mass spectrometer to compare the hit with standards. This natural product hit was identified as quercitrin (3-quercetin rhamnose) which is a known inhibitor of 15-LOX.

Supported by grant R01 AT007659 from the NIH NCCIH