In preparation....
A study of some Jamaican seaweeds revealed that the Jamaican variety of Laurencia
obtusa was avoided by Acantharus chirurgus (doctor fish) and its
chloroform-methanol extract was highly toxic to the fish.
In contrast, a second species of the same genus, Laurencia papillosa, was found to
be quite palatable. The absence of biological activity in Laurencia papillosa
compared to Laurencia obtusa prompted a chemical investigation of both species.
Investigation of Laurencia papillosa revealled that this particular species only contained a mixture of fats. Bioactivity studies, which included the brine shrimp assay and the fungal disc assay, were carried out on the chloroform-methanol extract of Laurencia papillosa. The results of these tests indicated that the extract contained no bioactive components.
On the other hand, Laurencia obtusa afforded the known toxin, (+)-elatol, in addition to two novel sesquiterpenes, 2-chloro-3-hydroxy-a-chamigren-9-one and 2-chloro-3,7-epoxy-a-chamigran-9-one, which were closely
related to elatol. The results of the tests showed that the extract and the
above-mentioned compounds were bioactive. |
Brennan M.R, Erickson K.L, Minott D.A. and Pascoe K.O,
Phytochemistry 1987, 26(4), 1053
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Created Feb 1995. Last modified 18th April-98.
URL http://wwwchem.uwimona.edu.jm:1104/lectures/marine.html