title: A possible role of partially pyrolysed essential oils in Australian Aboriginal traditional ceremonial and medicinal smoking applications of Eremophila longifolia (R. Br.) F. Muell (Scrophulariaceae).
abstract: BACKGROUND
  Eremophila longifolia is one of the most respected of the traditional medicines used by Australian Aboriginal people. Customary use involves smoldering the leaves over hot embers of a fire to produce an acrid smoke, believed to have therapeutic effects broadly consistent with antimicrobial, antifungal and anti-inflammatory capacity.
  
  
  OBJECTIVE
  The current study aims to examine the contribution of partially pyrolysed and non-pyrolysed essential oils in traditional usage of Eremophila longifolia.
  
  
  METHODS
  Non-pyrolysed and partially pyrolysed essential oils were produced by hydrodistillation and part-wet/part-dry distillation, respectively. All samples were tested for antimicrobial activity by broth dilution. Some of these samples were further treated to an incrementally stepped temperature profile in a novel procedure employing a commercial thermocycler in an attempt to mimic the effect of temperature gradients produced during smoking ceremonies. Components from the pyrodistilled oils were compared with the non-pyrodistilled oils, using GC-MS, GC-FID and HPLC-PAD. The 2,2-diphenyl-1-picrylhydrazyl method, was used to compare free radical scavenging ability.
  
  
  RESULTS
  Partially pyrolysed oils had approximately three or more times greater antimicrobial activity, enhanced in cultures warmed incrementally to 60°C and held for 30s and further enhanced if held for 2 min. Partially pyrolysed oils showed a radical scavenging capacity 30-700 times greater than the corresponding non-pyrolysed oils. HPLC-PAD revealed the presence of additional constituents not present in the fresh essential oil.
  
  
  CONCLUSIONS
  These results, by showing enhanced antimicrobial and antioxidant activities, provide the first known Western scientific justification for the smoking ceremonies involving leaves of Eremophila longifolia. During customary use, both partially pyrolysed as well as non-pyrolysed essential oils may contribute significantly to the overall intended medicinal effect.
authors.affiliation: University of New England, Pharmaceuticals, Nutraceuticals Group for Bioactive Discovery in Health and Ageing Science and Technology Armidale, Armidale, NSW 2351, Australia. nsadgrov@une.edu.au
authors.forename: N J
authors.initials: NJ
authors.lastname: Sadgrove
authors.forename: G L
authors.initials: GL
authors.lastname: Jones
mesh_terms: D000890:Anti-Infective Agents / Q000737:chemistry / Q000494:pharmacology*; D000975:Antioxidants / Q000737:chemistry / Q000494:pharmacology*; D001315:Australia; D002176:Candida albicans / Q000187:drug effects; D021902:Enterobacter aerogenes / Q000187:drug effects; D006358:Hot Temperature; D006801:Humans; D008519:Medicine, Traditional; D008826:Microbial Sensitivity Tests; D009822:Oils, Volatile / Q000737:chemistry / Q000494:pharmacology*; D028083:Scrophulariaceae; D012907:Smoking; D013211:Staphylococcus aureus / Q000187:drug effects; D013212:Staphylococcus epidermidis / Q000187:drug effects
chemical_list: D000890:Anti-Infective Agents; D000975:Antioxidants; D009822:Oils, Volatile