Polyhalogenated monoterpenes from a tasmanian collection of the red seaweed Plocamium cartilagineum.

Two new polyhalogenated monoterpenes (3E, 7E)-8-bromo-(2E)-chloromethylene-(5R, 6R)-dichloro-6-methyloctadien-1-al (1) and (1Z,3E,7E)-8,9-dibromo-(1Z,5R*, 6R*,9)-tetrachloro-6-methyloctatriene [corrected] (2), together with two known compounds (3 and 4), were isolated and identified from the red alga Plocamium cartilagineum collected along the eastern coast of Tasmania. The structures were established by spectroscopic techniques.

Metabolic fate of dietary terpenes fromEucalyptus radiata in common ringtail possum (Pseudocheirus peregrinus).

Arboreal marsupials consume terpenes in quantities that are toxic to other mammals, indicating that they possess special detoxification mechanisms. The metabolic fate of dietary terpenes was studied in the common ringtail possum (Pseudocheirus peregrinus). Three animals were fedEucalyptus radiata leaf for 10 days. Leaf consumption increased over three days to an average steady state of about 10-15 mmol total terpenes per day. GCMS analysis identified six urinary terpene metabolites, which were dicarboxylic acids, hydroxyacids, or lactones. Another nine metabolites could only be shown to be terpene-derived but of unknown structure. The amounts excreted were estimated by GC-FID, using response factors based on carbon content. Total 24-hr excretion of terpene-derived metabolites increased to 6.2-7.6 mmol on days 5-10, while glucuronic acid excretion remained constant at about 1.5 mmol. No other conjugates of terpene metabolites were found. The strategy used by the possum to detoxify dietary terpenes seems to be to polyoxygenate the molecules forming highly polar, acidic metabolites that can be readily excreted. Conjugation is minimal, perhaps to conserve carbohydrate and amino acids.

Distribution of amathamide alkaloids within single colonies of the bryozoanAmathia wilsoni.

The content and distribution of amathamide alkaloids within single colonies of the bryozoanAmathia wilsoni (Ctenostomata) varied depending on the location in the colony. Three colonies in all, collected from the same site at the same time, were analyzed and gave very similar results. The outermost, more exposed, tips of the colony had an alkaloid content of nearly 9% of dry weight, while basal parts were apparently devoid of alkaloids. Samples taken midway between tips and base yielded intermediate concentrations of about 1%. Very little variation in the proportions of individual amathamides A, B, C, E occurred between exposed tips of the colonies. However, some differences in ratios were found between tips from exposed and more protected regions.