Environmental Engineering Reference
In-Depth Information
351
and 24-methyl-12,24,25-trioxoscalar-16-en-22-oic acid
352
showed potent
antifouling activities. The antifouling activities of lactone
351
and aldehyde
352
show 90%and95%attheconcentrationin1 ppm. The value of the other
aldehyde
353
is 10% [23].
4
Nitrogen-containing Compounds
4.1
Introduction
One of representative natural products is an alkaloid which has a pharmaco-
logical effect. They are found in nature, usually in plants. They are nitroge-
nous organic molecules. The name derives from the word alkaline; origi-
nally, the term was used to describe any nitrogen-containing base (an amine
in modern terms). Some kinds of these alkaloids and the other nitrogen-
containing compounds also showed antifouling activities. They are hetero-
cyclic compounds (e.g., gramines, pyrrols, and pyrazoles), amides, carba-
mates, primary amines, peptides, etc. as shown in Table 5 [4, 28-47].
4.2
Hetrocyclic Compounds
4.2.1
Gramines
Many kinds of heterocyclic compounds such as gramines, pyrrols, and pyra-
zoles, show antifouling activities. Especially, 2,5,6-Tribromo-1-methylgramine
421
isolated from a marine bryozoan,
Zoobotryon pellucidum
,showedan-
tifouling activities against a barnacle
Balanus amphitrite
andabluemussel
Mytilus edulis
. The antifouling activities of 2,5,6-tribromo-1-methylgramine
and CuSO
4
against the blue mussels
Mytilus edulis
are shown in Table 6 [4],
and minimum inhibitory concentration for larval settlement and IC
30
values
of 2,5,6-tribromo-1-methylgramine and TBTO for reared cyprids are shown
in Table 7 [4]. The antifouling activity of 2,5,6-tribromo-1-methylgramine is
higher than that of CuSO
4
and its inhibitory activity was 6 times as strong as
that of TBTO, while its toxicity to the cyprid larvae was one-tenth of that of
TBTO. This substance also inhibited the settlement of the blue mussel
Mytilus
edulis
[4].
Recently, Kawamata et al. [28] synthesized approximately one hundred
kinds of gramine compounds. Of these compounds, 5,6-dichlorogramine
422
showed much higher antifouling activity than that of TBTO as shown in
Table 8 [28].
