Fermentation of Alternaria alternata k21-1, a fungus obtained from the surface of
the marine red alga Lomentaria hakodatensis collected from Kongdong Island, in
liquid PDB medium yielded four tetrahydrofuran-bearing meroterpenes,
tricycloalterfurenes AÀD (247–250) (Fig. 15) [84]. Another Alternaria strain
(Alternaria sp. JJY-32) was obtained from the sponge Callyspongia sp. collected
off the coast of Hainan Island. Fermentation of this fungus in PDB medium yielded
thirteen meroterpenoids with diverse ring systems, including tricycloalterarenes
AÀC (251–253), bicycloalternarenes AÀF (254–259), and monocycloalterarenes
AÀD (260–263). The compounds were tested for their NF-κB inhibitory activities in
RAW264.7 cells, but showed only weak bioactivities with IC 50 values ranging from
39 to 85 μM [85]. 1,2-Dihydroterretonin F (264) was produced in PDB medium with
addition of seawater by Aspergillus ustus cf-42, an endophyte obtained from the
fresh tissue of the marine green alga Codium fragile collected from Zhoushan
Island [86].
The fungal strain Aspergillus sp. ZL0-1b14 was obtained from the marine green
alga Enteromorpha sp. collected in the Jinjiang Dongshi salt pan, Fujian Province.
Aspertetranones AÀD (265–268), four highly oxygenated triketide-sesquiterpenoid
meroterpenes, were isolated following cultivation of this fungus on solid PDA
medium containing 20% NaCl. Aspertetranone D (268) suppressed the production
of IL-6 (69% inhibition at 40 μM) in LPS-stimulated RAW264.7 macrophages
[87]. The digestive gland of the crab Xenograpsus testudinatus collected from the
Kueishantao hydrothermal vents off Taiwan yielded Aspergillus sp. WU 243. A
novel hybrid polyketide-terpenoid, aspergstressin (269), was induced by adding
cobalt to the PDB medium employed for fermentation of this fungus (Fig. 15) [88].
O
O
O
O
OH
OH
239 R
1 = OH, R
2 = OMe, R 3 = OMe
(territrem D)
240 R
1 = OMe, R
2 = OH, R 3 = H
(territrem E)
R 1
R 2
R 3
O
O
O
O
O
O
241 (11a-dehydroxyisoterreulactone A)
OH
244 (pleosporallin C)
OH
O
OH
HO
245 (pleosporallin D)
OH
O
OH
HO
O
246 (craterellin D)
OH
O
OH
HO
HO
242 R 1 = CH 2 OH, R 2 = Me
(pleosporallin A)
243 R
1 = Me, R
2 = CH 2 OH
(pleosporallin B)
R 1 R 2
OH
O
OH
HO
Fig. 14 Structures of merosesquiterpenes (part 4)
Secondary Metabolites from Marine-Derived Fungi from China
105
the marine red alga Lomentaria hakodatensis collected from Kongdong Island, in
liquid PDB medium yielded four tetrahydrofuran-bearing meroterpenes,
tricycloalterfurenes AÀD (247–250) (Fig. 15) [84]. Another Alternaria strain
(Alternaria sp. JJY-32) was obtained from the sponge Callyspongia sp. collected
off the coast of Hainan Island. Fermentation of this fungus in PDB medium yielded
thirteen meroterpenoids with diverse ring systems, including tricycloalterarenes
AÀC (251–253), bicycloalternarenes AÀF (254–259), and monocycloalterarenes
AÀD (260–263). The compounds were tested for their NF-κB inhibitory activities in
RAW264.7 cells, but showed only weak bioactivities with IC 50 values ranging from
39 to 85 μM [85]. 1,2-Dihydroterretonin F (264) was produced in PDB medium with
addition of seawater by Aspergillus ustus cf-42, an endophyte obtained from the
fresh tissue of the marine green alga Codium fragile collected from Zhoushan
Island [86].
The fungal strain Aspergillus sp. ZL0-1b14 was obtained from the marine green
alga Enteromorpha sp. collected in the Jinjiang Dongshi salt pan, Fujian Province.
Aspertetranones AÀD (265–268), four highly oxygenated triketide-sesquiterpenoid
meroterpenes, were isolated following cultivation of this fungus on solid PDA
medium containing 20% NaCl. Aspertetranone D (268) suppressed the production
of IL-6 (69% inhibition at 40 μM) in LPS-stimulated RAW264.7 macrophages
[87]. The digestive gland of the crab Xenograpsus testudinatus collected from the
Kueishantao hydrothermal vents off Taiwan yielded Aspergillus sp. WU 243. A
novel hybrid polyketide-terpenoid, aspergstressin (269), was induced by adding
cobalt to the PDB medium employed for fermentation of this fungus (Fig. 15) [88].
O
O
O
O
OH
OH
239 R
1 = OH, R
2 = OMe, R 3 = OMe
(territrem D)
240 R
1 = OMe, R
2 = OH, R 3 = H
(territrem E)
R 1
R 2
R 3
O
O
O
O
O
O
241 (11a-dehydroxyisoterreulactone A)
OH
244 (pleosporallin C)
OH
O
OH
HO
245 (pleosporallin D)
OH
O
OH
HO
O
246 (craterellin D)
OH
O
OH
HO
HO
242 R 1 = CH 2 OH, R 2 = Me
(pleosporallin A)
243 R
1 = Me, R
2 = CH 2 OH
(pleosporallin B)
R 1 R 2
OH
O
OH
HO
Fig. 14 Structures of merosesquiterpenes (part 4)
Secondary Metabolites from Marine-Derived Fungi from China
105