| Summary: | ABSTRACT
The burning of selected indigenous plants and the inhalation of the smoke liberated from
them has been a widely accepted and practised form of administration in traditional healing
therapy dating back to as far as the Koi and San, and is a method still widely practised in
South Africa today. Inhalation has various advantages as a method of administration in both
allopathic and traditional practices. Not only is inhalation a highly effective mode of
administration because of its direct and local effect on the lungs for the treatment of
respiratory ailments, but also because of its ability to deliver drugs effectively systemically.
This study elucidated the rationale behind this widely practised treatment by examining
chromatographic and antimicrobial data. Five plants that are commonly administered
traditionally through inhalation were chosen: Heteropyxis natalensis, Myrothamnus
flabellifolius, Artemisia afra, Pellaea calomelanos, and Tarchonanthus camphoratus. An
apparatus was designed and constructed and the burning process that occurs in the traditional
setting was simulated with the selected plants. The induced volatile fraction (smoke) was
captured for analysis. Control solvent extracts were made for each plant using conventional
extraction solvents, methanol, acetone, water, and the essential oil of the aromatic plants was
also investigated. Antimicrobial assays revealed that the extracts (smoke) obtained after
burning had lower minimum inhibitory concentration (MIC) values than the corresponding
solvent extracts in most cases. For Klebsiella pneumoniae all five inhalation samples were far
more active than the conventional extracts. When tested against the pathogen B. cereus, M.
flabellifolius and P. calomelanos inhalation samples proved to exhibit superior antimicrobial
activity compared to the respective solvent extracts. Pellaea calomelanos inhalation extract
had the lowest MIC values compared to the solvent extracts for all pathogens (P.
calomelanos inhalation extract MIC values: 0.53; 1.00; 0.53; 0.53 mg/ml for S. aureus, B.
cereus, K. pneumoniae and C. neoformans respectively). Inhalation extracts exhibited
different chemical profiles from the solvent extracts of the same plant. For example, A. afra
inhalation extract had an abundance of peaks at various retention times from 3.2 to 5.4
minutes, which were not present in the chromatograms of the acetone and methanol extracts
of the same plant. These results, albeit preliminary, suggest that the chemistry and
antimicrobial activity of plants are influenced by the combustion process which is often used
in traditional healing rites.
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