title: Anti-mycobacterial natural products from the Canadian medicinal plant Juniperus communis.
abstract: BACKGROUND
  Common juniper, Juniperus communis, is amongst the plants most frequently used by the indigenous peoples of North America for medicinal purposes. The First Nations of the Canadian Maritimes use infusions of juniper primarily as a tonic and for the treatment of tuberculosis. Previous investigations of extracts derived from the aerial parts of J. communis have shown it to possess anti-mycobacterial activity. The aim of the study is to isolate and identify anti-mycobacterial constituents from the aerial parts of J. communis.
  
  
  METHODS
  Methanolic extracts of J. communis needles and branches were subjected to bioassay guided fractionation using the microplate resazurin assay (MRA) to assess inhibitory activity against Mycobacterium tuberculosis strain H37Ra. The anti-mycobacterial constituents were identified by NMR, MS and polarimetry.
  
  
  RESULTS
  The diterpenes isocupressic acid and communic acid and the aryltetralin lignan deoxypodophyllotoxin were isolated from the J. communis extract. Isocupressic acid and communic acid (isolated as an inseparable 3:2 mixture of cis and trans isomers) displayed MICs of 78 μM and 31 μM and IC(50)s of 46 μM and 15 μM against M. tuberculosis H37Ra respectively. Deoxypodophyllotoxin was less active, with a MIC of 1004 μM and an IC(50) of 287 μM.
  
  
  CONCLUSIONS
  Isocupressic acid, communic acid and deoxypodophyllotoxin were identified as the principal constituents responsible for the anti-mycobacterial activity of the aerial parts of J. communis. Although further research will be required to evaluate the relative activities of the two communic acid isomers, this work validates an ethnopharmacological use of this plant by Canadian First Nations and Native American communities.
authors.affiliation: Department of Biology, University of New Brunswick, Saint John, New Brunswick, Canada E2L 4L5.
authors.forename: Caitlyn D
authors.initials: CD
authors.lastname: Carpenter
authors.forename: Taryn
authors.initials: T
authors.lastname: O'Neill
authors.forename: Nadia
authors.initials: N
authors.lastname: Picot
authors.forename: John A
authors.initials: JA
authors.lastname: Johnson
authors.forename: Gilles A
authors.initials: GA
authors.lastname: Robichaud
authors.forename: Duncan
authors.initials: D
authors.lastname: Webster
authors.forename: Christopher A
authors.initials: CA
authors.lastname: Gray
mesh_terms: D000900:Anti-Bacterial Agents / Q000737:chemistry / Q000494:pharmacology*; D001688:Biological Products / Q000737:chemistry / Q000494:pharmacology; D002170:Canada; D002264:Carboxylic Acids / Q000302:isolation & purification / Q000494:pharmacology*; D004224:Diterpenes / Q000302:isolation & purification / Q000494:pharmacology*; D004365:Drugs, Chinese Herbal; D057809:HEK293 Cells; D006801:Humans; D018653:Juniperus; D008519:Medicine, Traditional; D008826:Microbial Sensitivity Tests; D009169:Mycobacterium tuberculosis / Q000187:drug effects / Q000254:growth & development; D035261:Plant Components, Aerial; D010936:Plant Extracts / Q000737:chemistry / Q000494:pharmacology*; D010946:Plants, Medicinal; D011034:Podophyllotoxin / Q000031:analogs & derivatives* / Q000302:isolation & purification / Q000494:pharmacology; D013764:Tetrahydronaphthalenes / Q000302:isolation & purification / Q000494:pharmacology*
chemical_list: D000900:Anti-Bacterial Agents; D001688:Biological Products; D002264:Carboxylic Acids; D004224:Diterpenes; D004365:Drugs, Chinese Herbal; D010936:Plant Extracts; D013764:Tetrahydronaphthalenes; C461919:communic acid; C110793:isocupressic acid; C014451:deoxypodophyllotoxin; D011034:Podophyllotoxin