This research aims to provide the pyrethrum industry with a better understanding of the chemistry behind the solubility and polymerisation of Sesquiterpene Lactones (SPLs), which are another compound found in pyrethrum.
The work is conducted in collaboration with Botanicals Resources Australia (BRA), a Tasmanian based company that is the world’s largest supplier of the natural insecticide pyrethrum.
SLPs are a class of co-extractives that can cause allergic reactions if they come in contact with the skin. They often precipitate during storage, creating unwanted debris in the final product.
This project will investigate the mechanism behind the process in pyrethrum oil and what combination of temperature and storage time minimises the polymerization and precipitation process.
The research will study the extraction profile of STLs in sub-critical CO2 extraction looking at the dependence of pressure, temperature and the concomitant fluid density on the extraction from pelletised pyrethrum.
Experiments will be undertaken to establish the relative solubility of STLs in hexane and related organic solvents, compared to those of the target pyrethrums.
In consultation with industry the project will compare the production of pyrethrin and STLs in selected high and low STL producing plants with view to understanding the mechanism for the regulation of the genes involved in STL production which may lead to ways to switch off of the STL synthesis.
Experiments will relate the conditions of temperature, oxygen and moisture to post-harvest production and/or degrading of the STLs prior to extraction.