A study of some New Zealand natural products.
Jogia, Madhu Kant
The barks of Pseudopanax colensoi and P. crassifolium were investigated in an attempt to identify potential deer attracting substances from the former. The bark of this species is among the first vegetation consumed when deer enter a new area of New Zealand native forest. Fatty acids and derivatives were isolated from both of the barks and analysed by g.l.c. Syringaresinol was isolated from the bark of P. crassifolium. A mixture of syringic acid and 5-hydroxymethylfurfural was extracted from P. colensoi. Ester and ether derivatives combining syringic acid and 5-hydroxymethylfurfural were synthesised. Carbohydrates were the major constituents of the bark of P. colensoi. H.P.L.C. analysis enabled the identification of glucose, arabinose, mannitol and galactitol, as free sugars and alditols from P. colensoi. P. crassifolium contained smaller amounts of galactitol, mannitol and glucose. H.P.L.C. retention data on a Waters 'Sugar Pak 1' ion-exchange column of most of the common monosaccharides, alditols and the isomeric inositols is presented for the first time. Water soluble polysaccharides, containing mostly arabinose and galactose units were extracted from the barks of the two Pseudopanax species. An arabinogalactoglucan from P. colensoi and an arabinogalactan from P. crassifolium were characterised by methylation analyses, g.c. -m.s., and ¹³C.n.m.r. The arabinogalactoglucan from P. colensoi was shown to be highly branched and contained at least eleven different residues. It was composed mostly of 1,3,6-linked galactopyranosyl units (25%), with glucose (19%) being the main terminal unit. Almost equal proportions of 1,6-linked galactopyranosyl (9%), 1,3- and 1,5-linked arabinofuranosyl (11% and 9%) and terminal arabinofuranosyl (9%) residues were present. Other arabinose and galactose units, each being less than 6%, were also identified. The arabinogalactan from P. crassifolium was also highly branched, as indicated by the large proportion of terminal arabinofuranosyl (30%) residues. The major branching and linked units were 1,3-arabinofuranosyl, 1,3,4,6-galactopyranosyl, 1,3,6-galactopyranosyl, 1,4,6-galactopyranosyl and 1,6-galactopyranosyl. Trials with tame deer established their preference for a cold water soluble fraction extracted from the bark of P. colensoi.
Advisor: Weavers, R T
Degree Name: Doctor of Philosophy
Degree Discipline: Chemistry
Publisher: University of Otago
Research Type: Thesis
xii, 348 leaves :col. ill. ; 30 cm. Includes bibliographical references. University of Otago department: Chemistry