Corals 7.2 Potential Pharmaceuticals from Soft Corals 185
Part A | 7.2
tralins A–D isolated from Taiwanese C. australis was
mildly cytotoxic [7.59]. Most diterpenoids, hirsutalins
A–H, isolated from C. hirsuta exhibited cytotoxicity
toward several cancer cell lines with two hirsutalins
being significantly anti-inflammatory in vitro [7.120].
An Indonesian Cladiella sp. produced cladielloides
A and B; the latter exhibited moderate cytotoxicity
toward CCRF-CEM (Human Caucasian acute lymphoblastic leukaemia) tumor cells as well as significant
inhibitory effects on superoxide anion generation and
elastase release by human neutrophils [7.121]. From
the same species, cladieunicellin H was purified with
moderate inhibitory effects on the generation of superoxide anion and the release of elastase by human
neutrophils [7.122].
Genus Klyxum
Nine diterpenoids, simplexins A–I, from Klyxum simplex were found to be cytotoxic toward a limited panel
of cancer cell lines, or to significantly inhibit the accumulation of the pro-inflammatory iNOS and COX2 proteins in RAW264.7 macrophage cells [7.123].
Three novel diterpenoids, namely klysimplexin sulfoxides A–C, were isolated from the cultured soft
coral K. simplex, which significantly inhibited the
accumulation of the pro-inflammatory iNOS protein
in RAW264.7 macrophage cells [7.124]. Diterpenoids
from Taiwanese K. molle named klymollins A–H displayed a similar activity together with significant in
vitro anti-inflammatory activity by inhibiting the expression of the iNOS protein [7.125].
Genus Paraminabea
The Formosan Paraminabea acronocephala yielded
withanolides, paraminabeolides A–F along with
minabeolides, which were either cytotoxic toward
Hep G2 cancer cells, or significantly inhibited the
accumulation of the pro-inflammatory iNOS protein,
or could effectively reduce the expression of COX-2
protein [7.126].
Genus Parerythropodium
Extracts of the Red Sea Parerythropodium fulvum fulvum exhibited antimicrobial activity against several
co-occurring and potentially pathogenic marine bacteria [7.40].
Genus Anthomastus
3-oxo-sterols were reported as moderately cytotoxic metabolites of Antarctic Anthomastus bathyproctus [7.127].
Genus Bellonella
The cytotoxic diterpene sarcodictyin A, which was
reported in the stoloniferan soft coral Sarcodictyon
roseum [7.76], was also isolated from Bellonella albiflora [7.113]. Sarcodictyin A showed strong cytotoxicity against HeLa human cervix cells.
7.2.2 Family Anthothelidae
Genus Erythropodium
The Caribbean octocoral Erythropodium caribaeorum provided methyl-caribaeorane, which was active in a cell-based assay for antimitotic activity at
10 mM [7.112].
7.2.3 Family Gorgoniidae
Both soft corals and gorgonians are abundant in tropical
reef habitats, with the Indo-Pacific being dominated by
soft corals and the western Atlantic reefs by gorgonians.
Both are prolific producers of terpenoids, especially
diterpenes [7.128]. Gorgonians (horny corals) from the
Caribbean were the first octocorals studied for antimicrobial activity of corals [7.129]. In the late 1960s and
early 1970s, it was discovered that some gorgonians
contain large quantities of prostaglandins rendering, in
part, the rapid growth of the field of marine natural
products. The corals that were found to possess antibacterial activity were Antillogorgia turgida, A. americana, Rhipidogorgia flabellum, Briareum asbestinum,
Plexaura homomalla, P. dichotoma, and Plexauropsis
crassa. In reference [7.27] the absolute configuration
and species distribution of 28 terpenoid compounds isolated from 19 species of gorgonians were described.
Over 200 novel secondary metabolites isolated from
gorgonians were discussed in [7.25], for many of which
the pharmacological effects were described in [7.130].
Extracts from eight coral species from San Blas Islands, Panama, [7.131] displayed intermediate levels
of antimicrobial activity against five marine and nonmarine bacteria. It was found that nonpolar fractions
were much more active than polar fractions. Extracts
of several species of 39 Caribbean gorgonians were
broadly studied against 15 strains of marine bacteria,
including marine opportunistic pathogens, and strains
isolated from healthy and decayed gorgonians inhibited
the growth of bacteria [7.132], hence, as the source of
a number of bioactive terpenoids. Nine of ten gorgonian
extracts from the four families tested showed antimicrobial activity against Gram-positive bacteria [7.133].
These corals, therefore, maintain a wealth of novel
Part A | 7.2
tralins A–D isolated from Taiwanese C. australis was
mildly cytotoxic [7.59]. Most diterpenoids, hirsutalins
A–H, isolated from C. hirsuta exhibited cytotoxicity
toward several cancer cell lines with two hirsutalins
being significantly anti-inflammatory in vitro [7.120].
An Indonesian Cladiella sp. produced cladielloides
A and B; the latter exhibited moderate cytotoxicity
toward CCRF-CEM (Human Caucasian acute lymphoblastic leukaemia) tumor cells as well as significant
inhibitory effects on superoxide anion generation and
elastase release by human neutrophils [7.121]. From
the same species, cladieunicellin H was purified with
moderate inhibitory effects on the generation of superoxide anion and the release of elastase by human
neutrophils [7.122].
Genus Klyxum
Nine diterpenoids, simplexins A–I, from Klyxum simplex were found to be cytotoxic toward a limited panel
of cancer cell lines, or to significantly inhibit the accumulation of the pro-inflammatory iNOS and COX2 proteins in RAW264.7 macrophage cells [7.123].
Three novel diterpenoids, namely klysimplexin sulfoxides A–C, were isolated from the cultured soft
coral K. simplex, which significantly inhibited the
accumulation of the pro-inflammatory iNOS protein
in RAW264.7 macrophage cells [7.124]. Diterpenoids
from Taiwanese K. molle named klymollins A–H displayed a similar activity together with significant in
vitro anti-inflammatory activity by inhibiting the expression of the iNOS protein [7.125].
Genus Paraminabea
The Formosan Paraminabea acronocephala yielded
withanolides, paraminabeolides A–F along with
minabeolides, which were either cytotoxic toward
Hep G2 cancer cells, or significantly inhibited the
accumulation of the pro-inflammatory iNOS protein,
or could effectively reduce the expression of COX-2
protein [7.126].
Genus Parerythropodium
Extracts of the Red Sea Parerythropodium fulvum fulvum exhibited antimicrobial activity against several
co-occurring and potentially pathogenic marine bacteria [7.40].
Genus Anthomastus
3-oxo-sterols were reported as moderately cytotoxic metabolites of Antarctic Anthomastus bathyproctus [7.127].
Genus Bellonella
The cytotoxic diterpene sarcodictyin A, which was
reported in the stoloniferan soft coral Sarcodictyon
roseum [7.76], was also isolated from Bellonella albiflora [7.113]. Sarcodictyin A showed strong cytotoxicity against HeLa human cervix cells.
7.2.2 Family Anthothelidae
Genus Erythropodium
The Caribbean octocoral Erythropodium caribaeorum provided methyl-caribaeorane, which was active in a cell-based assay for antimitotic activity at
10 mM [7.112].
7.2.3 Family Gorgoniidae
Both soft corals and gorgonians are abundant in tropical
reef habitats, with the Indo-Pacific being dominated by
soft corals and the western Atlantic reefs by gorgonians.
Both are prolific producers of terpenoids, especially
diterpenes [7.128]. Gorgonians (horny corals) from the
Caribbean were the first octocorals studied for antimicrobial activity of corals [7.129]. In the late 1960s and
early 1970s, it was discovered that some gorgonians
contain large quantities of prostaglandins rendering, in
part, the rapid growth of the field of marine natural
products. The corals that were found to possess antibacterial activity were Antillogorgia turgida, A. americana, Rhipidogorgia flabellum, Briareum asbestinum,
Plexaura homomalla, P. dichotoma, and Plexauropsis
crassa. In reference [7.27] the absolute configuration
and species distribution of 28 terpenoid compounds isolated from 19 species of gorgonians were described.
Over 200 novel secondary metabolites isolated from
gorgonians were discussed in [7.25], for many of which
the pharmacological effects were described in [7.130].
Extracts from eight coral species from San Blas Islands, Panama, [7.131] displayed intermediate levels
of antimicrobial activity against five marine and nonmarine bacteria. It was found that nonpolar fractions
were much more active than polar fractions. Extracts
of several species of 39 Caribbean gorgonians were
broadly studied against 15 strains of marine bacteria,
including marine opportunistic pathogens, and strains
isolated from healthy and decayed gorgonians inhibited
the growth of bacteria [7.132], hence, as the source of
a number of bioactive terpenoids. Nine of ten gorgonian
extracts from the four families tested showed antimicrobial activity against Gram-positive bacteria [7.133].
These corals, therefore, maintain a wealth of novel