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Abstract:
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Scaevola spinescens R.Br. has an anecdotal reputation as a cancer treatment amongst Aboriginal people and "outback" settlers of Western Australia. Because of a parliamentary declaration in 1969, the Chemistry Centre WA has issued an aqueous extract of the whole plant free of charge to terminally ill cancer patients. In 1972, a pharmacological study identified anti-5-HT activity in the aqueous plant extract provided by the Chemistry Centre. The active compound or compounds were not identified. Apar
The work described herein forms two parts viz, a phytochemical analysis of the plant material to identify potentially antitumour active constituents that might help explain or give a rational basis for the anecdotal reputation of Scaevola spinescens. and bio-assays of a range of extracts and isolated compounds investigating the therapeutic potential with regard to both cancer therapy and anti-5-HT activity.
The structural elucidation of the pentacyclic triterpenoid, myricadiol (4.23), a member of the taraxerene family, was achieved principally by NMR and mass spectrometry, together with comparison of properties against an authentic specimen. To the author's knowledge, the detailed MS analysis of this compound has not been reported. Also identified was a series of esters of myricadiol. These appear to be novel. A second compound the structure of which was elucidated principally via GC-MS and NMR spect
The results of NMR experiments were interpreted to give the tentative absolute configurations of the asymmetric carbons in the molecule as being IS, 7S, 1OR. A number of known, in vitro anti-tumour active compounds were identified as constituents of the organic solvent extracts. Those isolated and possessing moderate to significant activity included the pentacyclic triterpenoids, myricadiol (4.23) and lupeol (5.1), and the pyranocoumarin, xanthyletin (4.10). A single component of the aqueous extct viz. scaevolal (5.13) a derivative of the sesquiterpene, [alpha]-bisabolene was also identified as exhibiting significant anti-tumour action.
In vitro antitumour activity was determined using the Crown Gall Tumour Assay. A widely used cancer therapeutic agent, doxorubicin (8.1), was used to gauge the levels of tumour inhibition exhibited by the crude hexane, chloroform and methanol extracts, several derived fractions and the aforementioned single compounds isolated from the plant. Only preliminary results confirming the in vitro anti-5-HT activity screening of the organic solvent (hexane and methanol) soluble plant constituents are repor
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