Chemistry Reference
In-Depth Information
2.3.5
Indole Alkaloids
Many indole-containing metabolites have been reported from marine organisms,
some of which were already mentioned. This section focuses on important
indole-containing substances that belong to structural classes not mentioned
above. These alkaloids show antimicrobial, antiparasitic, antitumor, and enzyme
inhibitory activities (27). Dragmacidin (
86
) is a novel
bis
-indole isolated
from a deep-sea sponge
Dragmacidon
sp., whereas another deep-sea sponge
Spongosorites ruetzleri
contains a similar
bis
-indole, topsentin (
87
).
β
-Carboline-containing metabolites are known from sponges and tunicate.
Eudistomins were the first
β
-carboline alkaloid isolated from marine organisms.
Eudistomin K (
88
), which is a novel oxathiazepine ring containing
β
-carboline,
was isolated from the tunicate
Eudistoma olivaceum
, whereas a guanidine-
containing grossularine 1 (
89
) was from the tunicate
Dendrodoa grossulatia
(27).
N
NH
Me
N
O
Br
N
OH
O
S
N
H
NH
2
H
Br
Br
H
OH
Br
HN
H
H
886
887
888
NMe
2
O
CH
3
N
N
N
NH
NH
N
NCH
3
N
Br
N
H
O
H
Cl
N
O
HN
N
Br
NCH
3
H
H
O
HN
889
990
991
OH
OH
OH
HO
OH
OH
HO
O
N
O
H
N
N
N
O
HO
Cl
Cl
C
O
O
O
N
O
O
O
HN
Br
H
N
NH
O
N
H
OH
O
HN
O
992
993
Physostigmine alkaloids are often contained in bryozoans. The highly unusual
constituent is securine A (
90
) isolated from
Securiflustra securifrons
from the
North Sea. Another interesting physostigmine is urochordamine A (
91
) isolated as
a larval settlement inducer from the ascidian
Ciona savignyi
(30). Neosurugatoxin
(
92
), which is a causative agent of “ivory shellfish poisoning” isolated from the
gastropod
Babylonia japonica
, is a reversible nicotinic acetylcholine antagonist
(14). Its bacterial origin has been suggested. Finally, diazonamide A (
93
)isa
