title: Antimycobacterial triterpenes from the Canadian medicinal plant Sarracenia purpurea.
abstract: BACKGROUND
  The purple pitcher plant, Sarracenia purpurea, is a medicinal plant used by the Canadian First Nations to treat a wide variety of illnesses. The Mi'kmaq and Wolastoqiyik (Maliseet) peoples of Eastern Canada have traditionally used infusions of S. purpurea for the treatment of tuberculosis-like symptoms. Previous investigations have shown methanolic extracts of S. purpurea to possess antimycobacterial activity.
  
  
  OBJECTIVE
  To isolate and identify antimycobacterial constituents from S. purpurea.
  
  
  METHODS
  Methanolic extracts of S. purpurea were subjected to bioassay guided fractionation using the microplate resazurin assay (MRA) to assess inhibitory activity against Mycobacterium tuberculosis strain H37Ra. The antimycobacterial constituents were identified by NMR, MS and polarimetry.
  
  
  RESULTS
  The triterpenes betulinaldehyde, β-sitosterol, betulinic acid, and ursolic acid were isolated from S. purpurea. Betulinaldehyde, betulinic acid, and ursolic acid exhibited MICs of 450, 950, and 450μM and IC50s of 98, 169, and 93μM against M. tuberculosis H37Ra respectively whilst β-sitosterol was inactive (MIC and IC50 of >1000μM).
  
  
  CONCLUSIONS
  Betulinaldehyde, betulinic acid, and ursolic acid were identified as the principal constituents responsible for the antimycobacterial activity of S. purpurea. This work is consistent with the ethnopharmacological use of S. purpurea by Canadian First Nations as a treatment against infectious diseases.
authors.affiliation: Department of Biological Sciences, University of New Brunswick, Saint John, New Brunswick, Canada E2L 4L5.
authors.forename: Steven A
authors.initials: SA
authors.lastname: Morrison
authors.affiliation: Department of Biological Sciences, University of New Brunswick, Saint John, New Brunswick, Canada E2L 4L5.
authors.forename: Haoxin
authors.initials: H
authors.lastname: Li
authors.affiliation: Division of Infectious Diseases, Department of Medicine, Saint John Regional Hospital, Saint John, New Brunswick, Canada E2L 4L2.
authors.forename: Duncan
authors.initials: D
authors.lastname: Webster
authors.affiliation: Department of Biological Sciences, University of New Brunswick, Saint John, New Brunswick, Canada E2L 4L5.
authors.forename: John A
authors.initials: JA
authors.lastname: Johnson
authors.affiliation: Department of Biological Sciences, University of New Brunswick, Saint John, New Brunswick, Canada E2L 4L5; Department of Chemistry, University of New Brunswick, Saint John, New Brunswick, Canada E2L 4L5. Electronic address: cgray@unb.ca.
authors.forename: Christopher A
authors.initials: CA
authors.lastname: Gray
mesh_terms: D000900:Anti-Bacterial Agents / Q000302:isolation & purification / Q000494:pharmacology*; D066241:Carbon-13 Magnetic Resonance Spectroscopy; D013058:Mass Spectrometry; D000432:Methanol / Q000737:chemistry; D008826:Microbial Sensitivity Tests; D009169:Mycobacterium tuberculosis / Q000187:drug effects* / Q000254:growth & development; D053978:Pentacyclic Triterpenes; D008517:Phytotherapy; D010936:Plant Extracts / Q000302:isolation & purification / Q000494:pharmacology*; D010946:Plants, Medicinal; D066244:Proton Magnetic Resonance Spectroscopy; D052583:Sarraceniaceae / Q000737:chemistry*; D012997:Solvents / Q000737:chemistry; D014315:Triterpenes / Q000302:isolation & purification / Q000494:pharmacology*; D000094062:Betulinic Acid; D000097245:Ursolic Acid
chemical_list: D000900:Anti-Bacterial Agents; D000432:Methanol; D053978:Pentacyclic Triterpenes; D010936:Plant Extracts; D012997:Solvents; D014315:Triterpenes; D000094062:Betulinic Acid; D000097245:Ursolic Acid
keywords: Antimycobacterial; Betulinaldehyde; Betulinic acid; Mycobacterium tuberculosis; Sarracenia purpurea; Ursolic acid; β-Sitosterol