This work describes the isolation and structural elucidation of extractives from four species of the
Meliaceae and one of the Simaroubaceae families. All five species examined are endemic to the island
of Madagascar.
One novel seco-ring A protolimonoid with a bourjotinolone A-type side-chain was isolated from Turraea
sericea, while Malleastrum antsingyense yielded one known and one novel limonoid of the vilasinin
group. Neobeguea leandreana was found to contain three novel limonoids of the phragmalin class,
including a relatively rare 17-keto seco-ring D compound and one containing a oxidized C-19 methyl
group. Quivisia papinae has afforded eight novel and five known protolimonoids and limonoids of the
azadiradione, evodulone, and mexicanolide classes. Included among these are a mexicanolide group
limonoid with a 17-keto seco-ring D, and two further mexicanolide limonoids containing a hitherto
unreported 9a,11a-epoxide ring and a Δ 9(11)-double bond.
One C19 and four C20 quassinoids, of which one is novel, together with a known but rare triterpenoid,
were isolated from the Madagascan Simaroubaceae Samadera madagascariensis. These findings
support the suggestion that this species is closely related to, if not synonymous with, the companion
species Samadera indica and Quassia indica.
A literature survey on the effect of structural variations in ring B on coupling constants in 11,12-disubstituted havanensin-group limonoids was also undertaken, resulting in the observation of a
remarkable correlation between ring structure and coupling constant values for a wide range of
compounds isolated from different sources. An explanation for these observations is advanced. / Thesis (Ph.D.)-University of Natal, Durban, 2001.
| Identifer | oai:union.ndltd.org:netd.ac.za/oai:union.ndltd.org:ukzn/oai:http://researchspace.ukzn.ac.za:10413/3876 |
| Date | January 2001 |
| Creators | Coombes, Philip Hugh. |
| Contributors | Mulholland, Dulcie A. |
| Source Sets | South African National ETD Portal |
| Language | English |
| Detected Language | English |
| Type | Thesis |
Page generated in 0.0019 seconds