Volume 145, Issue 3, 13 February 2013, Pages 813–821
Chemical and biological characterisation of solvent extracts and essential oils from leaves and fruit of two Australian species of Pittosporum (Pittosporaceae) used in aboriginal medicinal practice
- Received 19 November 2012, Revised 12 December 2012, Accepted 14 December 2012, Available online 26 December 2012
Abstract
Ethnopharmacological significance
Although no known medicinal use for Pittosporum undulatum Vent. (Pittosporaceae) has been recorded, anecdotal evidence suggests that Australian Aboriginal people used Pittosporum angustifolium
Lodd., G. Lodd. & W. Lodd. topically for eczema, pruritis or to
induce lactation in mothers following child-birth and internally for
coughs, colds or cramps.
Aims of the study
Essential oil composition and bioactivity as well as differential solvent extract antimicrobial activity from Pittosporum angustifolium are investigated here first, to partially describe the composition of volatiles released in traditional applications of Pittosporum angustifolium
for colds or as a lactagogue, and second to investigate antibacterial
activity related to topical applications. Essential oils were also
investigated from Pittosporum undulatum Vent., first to enhance essential oil data produced in previous studies, and second as a comparison to Pittosporum angustifolium.
Materials and methods
Essential
oils were hydrodistilled from fruit and leaves of both species using a
modified approach to lessen the negative (frothing) effect of saponins.
This was achieved by floating pumice or pearlite obsidian over the
mixture to crush the suds formed while boiling. Essential oil extracts
were analysed using GC–MS, quantified using GC-FID then screened for
antimicrobial activity using a micro-titre plate broth dilution assay
(MIC). Using dichloromethane, methanol, hexane and H2O as solvents, extracts were produced from leaves and fruit of Pittosporum angustifolium and screened for antimicrobial activity and qualitative phytochemical character.
Results
Although the essential oil from leaves and fruit of Pittosporum undulatum demonstrated some component variation, the essential oil from fruits of Pittosporum angustifolium
had major constituents that strongly varied according to the
geographical location of collection, suggesting the existence of at
least two chemotypes; one with high abundance of acetic acid decyl
ester. This chemotype had high antimicrobial activity whilst the other
chemotype had only moderate antimicrobial activity against the three
microbial species investigated here. This result may support the
occurrence of geographical specificity with regard to
ethnopharmacological use. Antimicrobial activity screening of the
solvent extracts from Pittosporum angustifolium revealed the leaves to be superior to fruit, with water being the most suitable extraction solvent.
Conclusion
To the best of our knowledge, this study constitutes the first time essential oils, and solvent extracts from the fruits of Pittosporum angustifolium,
have been examined employing comprehensive chemical and biological
analysis. The essential oil composition presented in this paper,
includes components with structural similarity as chemosemiotic
compounds involved in mother–infant identification, which may have
significance with regard to traditional applications as a lactagogue.
Graphical abstract
Keywords
- Pittosporum angustifolium;
- Pittosporum undulatum;
- Essential oil;
- Acetic acid decyl ester;
- Antimicrobial activity
- Corresponding author. Postage: Science and Technology, McClymont Building, University of New England, Armidale, NSW 2351, Australia. Tel./fax: +61 48 1130 595.
