Chemistry Reference
In-Depth Information
a multitude of mixed biogenesis metabolites, have been discovered during the last
40 years according to MarinLit (University of Canterbury, New Zealand). Many
marine natural products have structural features previously unreported from ter-
restrial sources (3). Halogenated, especially brominated, and sulfated compounds
are often encountered as marine natural products. Arsenic compounds, in par-
ticular arsenobetaines and arsenosugars, are distributed widely in marine algae
and invertebrates. Recently, the first polyarsenic organic compound from Nature,
arsenicin A (
2
) was reported from the sponge
Echinochalina bargibanti
(4).
Also, several highly bioactive compounds with interesting modes of action have
been discovered from marine invertebrates. A considerable percentage of these
compounds was suggested or found to be derived from microorganisms. Indeed,
certain bivalves and ciguateric fishes become poisonous by feeding toxic dinoflag-
ellates or herbivorous ciguateric fish (5), whereas some cytotoxic metabolites of
sponges and tunicates are produced by symbiotic microorganisms (6).
This review describes bioactive compounds isolated from marine algae and
invertebrates with an emphasis on their uniqueness. Because of limited space,
metabolites from bacteria, cyanobacteria, and fungi cannot be included, although
some from cyanobacterial and endosymbiotic bacterial origins are described
(some reviews on metabolites of marine bacteria, cyanobacteria, and fungi are
provided in the “Further Reading” section). Structures and bioactivities are
described for compounds that represent natural product classes, but steroids and
carotenoids are not included.
O
HN
O
O
O
O
HO
As
HO
O
O
O
O
A
As
As
O
OH
OH
O
OH
2
1
3
2.1 POLYKETIDES AND FATTY ACID DERIVATIVES
A diverse array of polyketide metabolites are found in marine organisms, which
range from simple oxylipins to highly complex polyethers and macrolides. Par-
ticularly intriguing are “ladder-shaped” polyethers of dinofragellate origin and
sponge macrolides.
2.1.1 Fatty Acid Derivatives
Oxylipins, which are a major metabolite of fatty acids, are observed regularly
in seaweeds and opisthobrachs that feed on seaweeds. Aplydilactone (
3
), which
is an unusual oxylipin isolated from the sea hare
Aplysisa kurodai
, activates
