Fermentation of E. rubrum in PDB medium yielded 3β,5α-dihydroxy-10α-methyl6β-acetoxy-ergosta-7,22-diene (396) [123].
The fungus Aspergillus flavus cf-5 was isolated from the marine red alga
Corallina officinalis collected off the coast of Yantai. Fermentation of this fungus
in PDB medium yielded 3β,4α-dihydroxy-26-methoxyergosta-7,24(28)-dien-6-one
(397). Compound 397 possessed low inhibitory activity against AChE (inhibitory
rate 10.3% at 100 μg/cm
3 ) [124]. Asporyergosterol (398) was obtained from the
PDB culture of Aspergillus oryzae cf-2, which was isolated from the marine red alga
Heterosiphonia japonica collected off the coast of Yantai [125]. The fungus Rhizopus sp., isolated from the marine bryozoan Bugula sp. collected in Jiaozhou Bay,
was reported to produce six ergosterol derivatives, including 3β-hydroxy(22E,24R)-ergosta-5,8,22-trien-7,15-dione (399), 3α-hydroxy-(22E,24R)-ergosta5,8,14,22-tetraen-7-one (400), 3β,15β-dihydroxy-(22E,24R)-ergosta-5,8(14),22trien-7-one (401), 3β,15α-dihydroxy-(22E,24R)-ergosta-5,8(14),22-trien-7-one
(402), 3β-hydroxy-(22E,24R)-ergosta-5,8(14),22-trien-7,15-dione (403), and
5α,8α-epidioxy-23,(24R)-dimethylcholesta-6,9(11),22-trien-3β-ol (404) when cultured in liquid GYM medium. Compounds 399–404 showed significant cytotoxicity
against P388 cells and HL-60 cells with IC 50 values below 10 μM [126]. A highly
conjugated steroid, (22E)-ergosta-4,6,8(14),22,24(28)-pentaen-3-one (405), was
obtained from the liquid PDA medium culture of Aspergillus sp., which was isolated
from the inner part of the gorgonian Muricella abnormalis collected from the Xisha
Islands coral reef of the South China Sea. Compound 405 inhibited barnacle larval
settlement with an EC 50 value of 47.2 μM (Fig. 22) [127].
6 Peptides Including Diketopiperazines
6.1 Diketopiperazines
Aspergillus versicolor pt20 was obtained from the brown alga Sargassum
thunbergii, which was collected from Pingtan Island. The diketopiperazine 9ξ-O-2
(2,3-dimethylbut-3enyl)brevianamide Q (406) (Fig. 23) was isolated from fermentation of this fungus in liquid potato dextrose medium [121]. The endophytic fungus
Eurotium cristatum EN-220 was isolated from the brown alga Sargassum thunbergii
collected from the coast of Qingdao. Fermentation of E. cristatum on solid rice
medium yielded cristatumins AÀD (407–410), while addition of 0.6% peptone to
solid rice medium gave four additional indole diketopiperazines (411–414). Compounds 408 and 412 showed weak toxic activity in a brine shrimp assay (Artemia
salina) with LD 50 values of 156 and 46 μM [128, 129]. Epoxyisoechinulin A (415)
was obtained from soybean medium fermentation of Aspergillus ruber, which was
isolated from the crinoid Himerometra magnipinna collected from the coral reef
national reserve at Xuwen, Zhanjiang City, in Guangdong Province [130].
Fermentation on solid rice medium of Aspergillus sp. XS-20090066, isolated
from the gorgonian Dichotella gemmacea collected from the Xisha Islands coral
118
Z. Liu et al.
The fungus Aspergillus flavus cf-5 was isolated from the marine red alga
Corallina officinalis collected off the coast of Yantai. Fermentation of this fungus
in PDB medium yielded 3β,4α-dihydroxy-26-methoxyergosta-7,24(28)-dien-6-one
(397). Compound 397 possessed low inhibitory activity against AChE (inhibitory
rate 10.3% at 100 μg/cm
3 ) [124]. Asporyergosterol (398) was obtained from the
PDB culture of Aspergillus oryzae cf-2, which was isolated from the marine red alga
Heterosiphonia japonica collected off the coast of Yantai [125]. The fungus Rhizopus sp., isolated from the marine bryozoan Bugula sp. collected in Jiaozhou Bay,
was reported to produce six ergosterol derivatives, including 3β-hydroxy(22E,24R)-ergosta-5,8,22-trien-7,15-dione (399), 3α-hydroxy-(22E,24R)-ergosta5,8,14,22-tetraen-7-one (400), 3β,15β-dihydroxy-(22E,24R)-ergosta-5,8(14),22trien-7-one (401), 3β,15α-dihydroxy-(22E,24R)-ergosta-5,8(14),22-trien-7-one
(402), 3β-hydroxy-(22E,24R)-ergosta-5,8(14),22-trien-7,15-dione (403), and
5α,8α-epidioxy-23,(24R)-dimethylcholesta-6,9(11),22-trien-3β-ol (404) when cultured in liquid GYM medium. Compounds 399–404 showed significant cytotoxicity
against P388 cells and HL-60 cells with IC 50 values below 10 μM [126]. A highly
conjugated steroid, (22E)-ergosta-4,6,8(14),22,24(28)-pentaen-3-one (405), was
obtained from the liquid PDA medium culture of Aspergillus sp., which was isolated
from the inner part of the gorgonian Muricella abnormalis collected from the Xisha
Islands coral reef of the South China Sea. Compound 405 inhibited barnacle larval
settlement with an EC 50 value of 47.2 μM (Fig. 22) [127].
6 Peptides Including Diketopiperazines
6.1 Diketopiperazines
Aspergillus versicolor pt20 was obtained from the brown alga Sargassum
thunbergii, which was collected from Pingtan Island. The diketopiperazine 9ξ-O-2
(2,3-dimethylbut-3enyl)brevianamide Q (406) (Fig. 23) was isolated from fermentation of this fungus in liquid potato dextrose medium [121]. The endophytic fungus
Eurotium cristatum EN-220 was isolated from the brown alga Sargassum thunbergii
collected from the coast of Qingdao. Fermentation of E. cristatum on solid rice
medium yielded cristatumins AÀD (407–410), while addition of 0.6% peptone to
solid rice medium gave four additional indole diketopiperazines (411–414). Compounds 408 and 412 showed weak toxic activity in a brine shrimp assay (Artemia
salina) with LD 50 values of 156 and 46 μM [128, 129]. Epoxyisoechinulin A (415)
was obtained from soybean medium fermentation of Aspergillus ruber, which was
isolated from the crinoid Himerometra magnipinna collected from the coral reef
national reserve at Xuwen, Zhanjiang City, in Guangdong Province [130].
Fermentation on solid rice medium of Aspergillus sp. XS-20090066, isolated
from the gorgonian Dichotella gemmacea collected from the Xisha Islands coral
118
Z. Liu et al.