Thesis
Low-volatile Extractive Compounds in Early Melaleuca alternifolia Seedlings
Southern Cross University
Master of Science (MSc), Southern Cross University
2022
DOI:
https://doi.org/10.25918/thesis.260
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Abstract
Melaleuca alternifolia (Australian Tea Tree) is an important medicinal plant. It has a history of being used for medicine first by indigenous and then non-indigenous peoples of Australia and worldwide. While the volatile components of the steam-distilled essential oil are well studied, the low-volatile components are largely unknown. Liquid chromatography and mass spectrometry methods were adopted and modified to separate, isolate, characterise, and quantify four low-volatile acylphloroglucinols in early Melaleuca alternifolia seedlings. Determination of the quantity and concentration of the acylphloroglucinols during the early seedling development showed an increase in quantity and a decrease in the concentration of the acylphloroglucinols as the early tea tree seedlings developed. Furthermore, a metabolomic study assessed changes in molecules at different ontogenetic growth stages of 14-month-old juvenile tea tree saplings using a sensitive liquid chromatography time-of-flight (LC-QTOF) method. Statistical analysis using R-Studio provided a library of signals for further elucidation of low-volatile compounds in the leaves of early Melaleuca alternifolia growth stages. Principal component analysis determined that variations in concentration of molecules between different ontogenetic stages of plant growth occurred within the sapling. Compounds were compared to a library of known compounds in closely related Melaleuca and Callistemon sp. and known monomeric acylphloroglucinols. Of 130 different molecular formulas, 112 were tentatively identified from the sensitive LC-TOF. This study enhances current knowledge of the chemistry of Melaleuca alternifolia, elucidates and describes four monomeric acylphloroglucinols for the first time in Melaleuca alternifolia: callisalignone A, pulverulentone B, 1-(2,6-dihydroxy-4-methoxy-3-methylphenyl)-2-methylpropan-1-one, and 1-(2,6-dihydroxy-4-methoxyphenyl)-3-methylbutan-1-one. A library of accurate mass and retention time for 100 low-volatile extractive compounds observed in a metabolomic study of 14-month-old saplings provides a starting point for future research.
Details
- Title
- Low-volatile Extractive Compounds in Early Melaleuca alternifolia Seedlings
- Creators
- Janelle Joy Schafer
- Contributors
- Ben Liu (Supervisor) - Southern Cross UniversityIan Southwell (Supervisor) - Southern Cross UniversitySimon Williams (Supervisor) - Southern Cross University
- Awarding Institution
- Southern Cross University; Master of Science (MSc)
- Theses
- Master of Science (MSc), Southern Cross University
- Publisher
- Southern Cross University
- Number of pages
- 175
- Identifiers
- 991013104413502368
- Copyright
- © JJ Schafer 2022
- Academic Unit
- Faculty of Science and Engineering; Southern Cross Plant Science
- Resource Type
- Thesis