title: Diversity-oriented natural product platform identifies plant constituents targeting Plasmodium falciparum.
abstract: A diverse library of pre-fractionated plant extracts, generated by an automated high-throughput system, was tested using an in vitro anti-malarial screening platform to identify known or new natural products for lead development. The platform identifies hits on the basis of in vitro growth inhibition of Plasmodium falciparum and counter-screens for cytotoxicity to human foreskin fibroblast or embryonic kidney cell lines. The physical library was supplemented by early-stage collection of analytical data for each fraction to aid rapid identification of the active components within each screening hit.
  
  
  
  A total of 16,177 fractions from 1300 plants were screened, identifying several P. falciparum inhibitory fractions from 35 plants. Although individual fractions were screened for bioactivity to ensure adequate signal in the analytical characterizations, fractions containing less than 2.0 mg of dry weight were combined to produce combined fractions (COMBIs). Fractions of active COMBIs had EC50 values of 0.21-50.28 and 0.08-20.04 µg/mL against chloroquine-sensitive and -resistant strains, respectively. In Berberis thunbergii, eight known alkaloids were dereplicated quickly from its COMBIs, but berberine was the most-active constituent against P. falciparum. The triterpenoids α-betulinic acid and β-betulinic acid of Eugenia rigida were also isolated as hits. Validation of the anti-malarial discovery platform was confirmed by these scaled isolations from B. thunbergii and E. rigida.
  
  
  
  These results demonstrate the value of curating and exploring a library of natural products for small molecule drug discovery. Attention given to the diversity of plant species represented in the library, focus on practical analytical data collection, and the use of counter-screens all facilitate the identification of anti-malarial compounds for lead development or new tools for chemical biology.
authors.affiliation: National Center for Natural Products Research, Research Institute of Pharmaceutical Sciences, School of Pharmacy, The University of Mississippi, University, MS, 38677, USA.
authors.forename: Jin
authors.initials: J
authors.lastname: Zhang
authors.affiliation: Department of Chemical Biology and Therapeutics, St. Jude Children's Research Hospital, Memphis, TN, 38105, USA.
authors.forename: John J
authors.initials: JJ
authors.lastname: Bowling
authors.affiliation: Department of Chemical Biology and Therapeutics, St. Jude Children's Research Hospital, Memphis, TN, 38105, USA.|Genentech, San Francisco, CA, USA.
authors.forename: David
authors.initials: D
authors.lastname: Smithson
authors.affiliation: Department of Chemical Biology and Therapeutics, St. Jude Children's Research Hospital, Memphis, TN, 38105, USA.
authors.forename: Julie
authors.initials: J
authors.lastname: Clark
authors.affiliation: National Center for Natural Products Research, Research Institute of Pharmaceutical Sciences, School of Pharmacy, The University of Mississippi, University, MS, 38677, USA.
authors.forename: Melissa R
authors.initials: MR
authors.lastname: Jacob
authors.affiliation: National Center for Natural Products Research, Research Institute of Pharmaceutical Sciences, School of Pharmacy, The University of Mississippi, University, MS, 38677, USA.
authors.forename: Shabana I
authors.initials: SI
authors.lastname: Khan
authors.affiliation: National Center for Natural Products Research, Research Institute of Pharmaceutical Sciences, School of Pharmacy, The University of Mississippi, University, MS, 38677, USA.|Department of Biomolecular Sciences and Research Institute of Pharmaceutical Sciences, School of Pharmacy, The University of Mississippi, University, MS, 38677, USA.
authors.forename: Babu L
authors.initials: BL
authors.lastname: Tekwani
authors.affiliation: Department of Chemical Biology and Therapeutics, St. Jude Children's Research Hospital, Memphis, TN, 38105, USA.
authors.forename: Michele
authors.initials: M
authors.lastname: Connelly
authors.affiliation: National Center for Natural Products Research, Research Institute of Pharmaceutical Sciences, School of Pharmacy, The University of Mississippi, University, MS, 38677, USA.|Keiser University, West Palm Beach, FL, USA.
authors.forename: Vladimir
authors.initials: V
authors.lastname: Samoylenko
authors.affiliation: National Center for Natural Products Research, Research Institute of Pharmaceutical Sciences, School of Pharmacy, The University of Mississippi, University, MS, 38677, USA.
authors.forename: Mohamed A
authors.initials: MA
authors.lastname: Ibrahim
authors.affiliation: National Center for Natural Products Research, Research Institute of Pharmaceutical Sciences, School of Pharmacy, The University of Mississippi, University, MS, 38677, USA.|Beni-Suef University, Beni-Suef, Egypt.
authors.forename: Mohamed A
authors.initials: MA
authors.lastname: Zaki
authors.affiliation: National Center for Natural Products Research, Research Institute of Pharmaceutical Sciences, School of Pharmacy, The University of Mississippi, University, MS, 38677, USA.
authors.forename: Mei
authors.initials: M
authors.lastname: Wang
authors.affiliation: National Center for Natural Products Research, Research Institute of Pharmaceutical Sciences, School of Pharmacy, The University of Mississippi, University, MS, 38677, USA.
authors.forename: John P
authors.initials: JP
authors.lastname: Hester
authors.affiliation: Department of Chemical Biology and Therapeutics, St. Jude Children's Research Hospital, Memphis, TN, 38105, USA.
authors.forename: Ying
authors.initials: Y
authors.lastname: Tu
authors.affiliation: Department of Chemical Biology and Therapeutics, St. Jude Children's Research Hospital, Memphis, TN, 38105, USA.
authors.forename: Cynthia
authors.initials: C
authors.lastname: Jeffries
authors.affiliation: Department of Chemical Biology and Therapeutics, St. Jude Children's Research Hospital, Memphis, TN, 38105, USA.
authors.forename: Nathaniel
authors.initials: N
authors.lastname: Twarog
authors.affiliation: Department of Chemical Biology and Therapeutics, St. Jude Children's Research Hospital, Memphis, TN, 38105, USA.
authors.forename: Anang A
authors.initials: AA
authors.lastname: Shelat
authors.affiliation: National Center for Natural Products Research, Research Institute of Pharmaceutical Sciences, School of Pharmacy, The University of Mississippi, University, MS, 38677, USA.|Department of Biomolecular Sciences and Research Institute of Pharmaceutical Sciences, School of Pharmacy, The University of Mississippi, University, MS, 38677, USA.
authors.forename: Larry A
authors.initials: LA
authors.lastname: Walker
authors.affiliation: National Center for Natural Products Research, Research Institute of Pharmaceutical Sciences, School of Pharmacy, The University of Mississippi, University, MS, 38677, USA. milias@olemiss.edu.
authors.forename: Ilias
authors.initials: I
authors.lastname: Muhammad
authors.affiliation: Department of Chemical Biology and Therapeutics, St. Jude Children's Research Hospital, Memphis, TN, 38105, USA. kip.guy@stjude.org.
authors.forename: R Kiplin
authors.identifier: 0000-0002-9638-2060
authors.initials: RK
authors.lastname: Guy
mesh_terms: D000962:Antimalarials / Q000302:isolation & purification / Q000494:pharmacology* / Q000633:toxicity; D001688:Biological Products / Q000302:isolation & purification / Q000494:pharmacology* / Q000633:toxicity; D002470:Cell Survival / Q000187:drug effects; D002478:Cells, Cultured; D004847:Epithelial Cells / Q000187:drug effects; D005347:Fibroblasts / Q000187:drug effects; D057166:High-Throughput Screening Assays; D006801:Humans; D010936:Plant Extracts / Q000302:isolation & purification / Q000494:pharmacology* / Q000633:toxicity; D010944:Plants / Q000737:chemistry*; D010963:Plasmodium falciparum / Q000187:drug effects*
chemical_list: D000962:Antimalarials; D001688:Biological Products; D010936:Plant Extracts
keywords: Alkaloids; Antimalarial; Berberis thunbergii; Drug discovery; Eugenia rigida; Natural products; Plasmodium falciparum; Spectrometry; Terpenes; UPLC-ELSD-PDA-ESI–MS