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Isolation and structural determination of polyphenols in Tasmanian eucalypts

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Brown, RB (1973) Isolation and structural determination of polyphenols in Tasmanian eucalypts. Coursework Master thesis, University of Tasmania.

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Abstract

Chapter 1 contains a brief review of chemotaxonomy as it relates to the classification of
eucalypts.
Particular reference is made to a chromatographic survey by Hillis of the low molecular weight
polyphenols on eucalypt leaves.
That survey provisionally identified a number of polyphenols of known structure but labelled other
compounds "Unknowns", because of the lack of evidence
for the identification of their structure.
The present work recounts the isolation and examination of the polyphenols in the leaves of three
Eucalypt species important to Tasmania: E. delegatensis, E. sieberiand E. coccifera.
Chapter 2 gives experimental details of the isolation of polyphenols from these species especially
the isolation of some of Hillis' unknowns.
Chapter 3 describes the experimental techniques by which evidence for the identity of the isolated
polyphenols has been gathered.
Chapter 4 then discusses the identity of these polyphenols. First to be identified are a number of
known polyphenols: gallic, gentisic and protocatechuic acids; quercetin, myricetin,
kaempferol; the flavonol glycosides, afzelin, rutin, quercitrin, isoquercitrin, hyperin and cannabiscitrin;
ellagic acid and (+)-catechin.
Secondly, some of Hillis' unknowns have been isolated and identified.
Unknown D has been isolated
(1) from E. sieberi and is identified as a mixture
of flavanones: pinocembrin, alpinetin and a
new natural product, 0,0-.dimethylpinocembrin;
(2) from E. coccifera and is identified as a mixture
of flavones: apigenin and two C-methylflavones,
sideroxylin and 4', 5-dihydroxy-7-methoxy-6-
methylflavone, the last identified provisionally.
Unknown A is identified as 4-0-methylellagic acid,
a new ellagic acid ether.
Unknown B is provisionally identified as a new
lignan, 1,5-dimethy1-2, 6-bis (trihydroxyphenyl) furo -
[1,5-c] furan.
Unknown F is tentatively given the structure of
a tetrahydroxydibenzofuran-dicarboxylic acid isomer.

Throughout the discussion the use of chromatography
of mixtures to provide evidence for chemotaxonomy
is critically considered.

Item Type: Thesis (Coursework Master)
Keywords: Eucalyptus, Phenols
Copyright Holders: The Author
Copyright Information:

Copyright 1973 the Author - The University is continuing to endeavour to trace the copyright
owner(s) and in the meantime this item has been reproduced here in good faith. We
would be pleased to hear from the copyright owner(s).

Additional Information:

Thesis (M.Sc.) - Tasmania, 1974. Bibliography: p. 175-182

Date Deposited: 25 Nov 2014 00:39
Last Modified: 11 Mar 2016 05:56
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