Ian A van Altena

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Flavonoids (1-4), together with ten known compounds (5-14) were isolated from the stems and roots of the mangrove plant Derris indica. Their chemical structures were elucidated by analysis of their spectroscopic data. All compounds except compounds 2 and 6 exhibited antimycobacterial activity with minimum inhibitory concentrations (MIC) between 6.25 and 200(More)
The structure of trisphaerolide A (1), a mildly cytotoxic metabolite isolated from extracts of the marine sponge Erylus trisphaerus collected in Dominica, has been elucidated by detailed analysis of spectroscopic data. Trisphaerolide A (1) has a putative polyketide biogenesis, incorporating a rare variant on the standard pathway, which involves the addition(More)
While the pharmacological and toxicological properties of eucalypts are well known in indigenous Australian medicinal practice, investigations of the bioactivity of eucalypt extracts against high mortality diseases such as pancreatic cancer in Western medicine have to date been limited, particularly amongst the genera Corymbia and Angophora. Four Angophora(More)
Six cyclised tetraprenyltoluquinols and five stereoisomers with the previously reported amentol skeleton have been isolated from the lipophilic extract of the South African brown alga Cystophora fibrosa. Structures and relative stereochemistry were determined using spectrometric techniques, particularly 1D and 2D NMR, and molecular modelling experiments.(More)
Investigation of an extract of the Australian marine sponge Psammoclema sp. for dynamin I inhibitory activity led to the isolation of four new trihydroxysterols (1-4) related to aragusterol G. These compounds were largely identified by 1D and 2D NMR spectroscopic methods. While 1 was found to be inactive in the dynamin bioassay, bioassays did reveal that(More)
Detailed spectroscopic and cytotoxicity data are reported for two new isoquinolinequinones, perfragilins A [1] and B [2], which were isolated from the bryozoan Membranipora perfragilis collected in South Australia. Both compounds, which are speculated to be of microbial origin, contain a relatively uncommon thiomethyl ether functionality.
In spite of the recent advancements in oncology, the overall survival rate for pancreatic cancer has not improved over the last five decades. Eucalypts have been linked with cytotoxic and anticancer properties in various studies; however, there is very little scientific evidence that supports the direct role of eucalypts in the treatment of pancreatic(More)
BACKGROUND The current investigation sought to explore the nature of the secondary metabolites in the algae, Laurencia pacifica. RESULTS This report details the first isolation of the sesquiterpenes isoaplysin (1), isolaurenisol (2), debromoisolaurinterol (3), debromoaplysinol (4), laur-11-en-10-ol (5), 10α-hydroxyldebromoepiaplysin (6), and the(More)
A new cytotoxic aromatic alkaloid, pantherinine [1], and a mixture of nucleosides including 7-deazainosine [3], have been isolated from the ascidian Aplidium pantherinum collected at Stenhouse Bay, South Australia. The structures were determined primarily from 1H- and 13C-nmr data, especially one-bond and multiple-bond proton-carbon correlations. Although(More)
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