8-hydroxyconiothyrinone B (85), 8,11-dihydroxyconiothyrinone B (86), (4S),8dihydroxy-10-O-methyldendryol E (87), (4R),8-dihydroxyconiothyrinone B (88),
and (4S),8-dihydroxyconiothyrinone B (89). Compounds 85–89 showed inhibitory
activity against Staphylococcus aureus with MIC values ranging from 7 to 26 μM. In
the antioxidant assay, compounds 85–89 displayed DPPH radical-scavenging activity with IC 50 values ranging from 12 to 52 μM, somewhat more potent than that of
BHT, a well-known antioxidant (IC 50 61 μM ). In addition, compounds 85–89
showed moderate ABTS radical-scavenging activity with IC 50 values ranging from
8.3 to 34 μM, comparable to the positive control ascorbic acid (IC 50 16 μM )
[45]. Five hydroanthraquinone derivatives, tetrahydroaltersolanols CÀF (90–93)
and dihydroaltersolanol A (94), together with five alterporriol-type anthranoid
dimers, alterporriols NÀR (95–99), were isolated from the potato glucose liquid
medium fermentation of Alternaria sp. ZJ-2008003, a fungus obtained from the soft
coral Sarcophyton sp. collected from the Weizhou coral reef in the South China Sea.
Alterporriol O (96) represents the first alterporriol dimer with a C-4–C-4
0 linkage.
Tetrahydroaltersolanol C (90) and alterporriol Q (98) exhibited antiviral activity
against the porcine reproductive and respiratory syndrome virus (PRRSV) with IC 50
values of 65 and 39 μM. Alterporriol P (97) showed cytotoxic activity against the
PC-3 and HCT-116 cell lines with IC 50 values of 6.4 and 8.6 μM [46]. The fungal
strain Nigrospora sp. was isolated from the zoanthid Palythoa haddoni collected
from the Weizhou coral reefs in the South China Sea. Fermentation of this fungus in
potato glucose liquid medium gave the hydroanthraquinone dimer nigrodiquinone A
(100) featuring the rare C-9–C-7
0 linkage (Fig. 6) [47].
2.5 Other Aromatic Polyketides
The endophytic fungus Cladosporium cladosporioides EN-399 (Plate 1) was isolated from the marine red alga Laurencia okamurai (Plate 2) collected from
Qingdao.
From the rice solid medium culture of C. cladosporioides, five cladosporol
derivatives, cladosporols FÀJ (101–105) (Fig. 7), were obtained. Cladosporol H
(103) showed significant cytotoxicity against the A549, Huh7, and LM3 cell lines
with IC 50 values of 5.0, 1.0, and 4.1 μM, respectively, while cladosporol I (104)
showed activity against the H446 lung cancer cell line with an IC 50 value of 4.0 μM
[48]. The red alga Laurencia sp. collected from Weizhou Island in the South China
Sea yielded two fungal strains, Alternaria alternata and Penicillium chrysogenum
QEN-24S. Two perylene derivatives, 7-epi-8-hydroxyaltertoxin I (106) and 6-epistemphytriol (107), were obtained from seawater-containing liquid GPY medium
fermentation of A. alternata [49], while 2-(2,4-dihydroxy-6-methylbenzoyl)-glycerol (108) was isolated from the solid rice culture of P. chrysogenum [24].
The fungus Pleosporales sp. was isolated from the green alga Enteromorpha
clathrata collected from the South China Sea in Hainan Province. From Czapek’s
liquid medium fermentation of this fungus, pleosporallin E (109) was obtained,
Secondary Metabolites from Marine-Derived Fungi from China
93
and (4S),8-dihydroxyconiothyrinone B (89). Compounds 85–89 showed inhibitory
activity against Staphylococcus aureus with MIC values ranging from 7 to 26 μM. In
the antioxidant assay, compounds 85–89 displayed DPPH radical-scavenging activity with IC 50 values ranging from 12 to 52 μM, somewhat more potent than that of
BHT, a well-known antioxidant (IC 50 61 μM ). In addition, compounds 85–89
showed moderate ABTS radical-scavenging activity with IC 50 values ranging from
8.3 to 34 μM, comparable to the positive control ascorbic acid (IC 50 16 μM )
[45]. Five hydroanthraquinone derivatives, tetrahydroaltersolanols CÀF (90–93)
and dihydroaltersolanol A (94), together with five alterporriol-type anthranoid
dimers, alterporriols NÀR (95–99), were isolated from the potato glucose liquid
medium fermentation of Alternaria sp. ZJ-2008003, a fungus obtained from the soft
coral Sarcophyton sp. collected from the Weizhou coral reef in the South China Sea.
Alterporriol O (96) represents the first alterporriol dimer with a C-4–C-4
0 linkage.
Tetrahydroaltersolanol C (90) and alterporriol Q (98) exhibited antiviral activity
against the porcine reproductive and respiratory syndrome virus (PRRSV) with IC 50
values of 65 and 39 μM. Alterporriol P (97) showed cytotoxic activity against the
PC-3 and HCT-116 cell lines with IC 50 values of 6.4 and 8.6 μM [46]. The fungal
strain Nigrospora sp. was isolated from the zoanthid Palythoa haddoni collected
from the Weizhou coral reefs in the South China Sea. Fermentation of this fungus in
potato glucose liquid medium gave the hydroanthraquinone dimer nigrodiquinone A
(100) featuring the rare C-9–C-7
0 linkage (Fig. 6) [47].
2.5 Other Aromatic Polyketides
The endophytic fungus Cladosporium cladosporioides EN-399 (Plate 1) was isolated from the marine red alga Laurencia okamurai (Plate 2) collected from
Qingdao.
From the rice solid medium culture of C. cladosporioides, five cladosporol
derivatives, cladosporols FÀJ (101–105) (Fig. 7), were obtained. Cladosporol H
(103) showed significant cytotoxicity against the A549, Huh7, and LM3 cell lines
with IC 50 values of 5.0, 1.0, and 4.1 μM, respectively, while cladosporol I (104)
showed activity against the H446 lung cancer cell line with an IC 50 value of 4.0 μM
[48]. The red alga Laurencia sp. collected from Weizhou Island in the South China
Sea yielded two fungal strains, Alternaria alternata and Penicillium chrysogenum
QEN-24S. Two perylene derivatives, 7-epi-8-hydroxyaltertoxin I (106) and 6-epistemphytriol (107), were obtained from seawater-containing liquid GPY medium
fermentation of A. alternata [49], while 2-(2,4-dihydroxy-6-methylbenzoyl)-glycerol (108) was isolated from the solid rice culture of P. chrysogenum [24].
The fungus Pleosporales sp. was isolated from the green alga Enteromorpha
clathrata collected from the South China Sea in Hainan Province. From Czapek’s
liquid medium fermentation of this fungus, pleosporallin E (109) was obtained,
Secondary Metabolites from Marine-Derived Fungi from China
93